Coronavirus news & views

Politics: A Risk Factor For Death From COVID?

What are you gonna believe, medical science or dubious talking heads?

In 2021 former Green Bay Packers quarterback, Aaron Rodgers, said he was “immunized” against COVID. He wasn’t. He claimed to have done “research” and learned how to get an infusion of antibodies and take some unproven ‘medicine.’ His ‘research’ was talking to radio pundit and hot-air purveyor, Joe Rogan. How many more people like Rodgers listen to the wisdom of the likes of Rogan or Tucker Carlson and think they know more than medical professionals and then rationalize their avoidance of COVID vaccines? And to what effect?

The Kaiser Family Foundation estimates that from June 2021 through March 2022 about 234,000 COVID deaths could have been prevented had the decedents been vaccinated against the SARS-CoV-2 virus. That protection was especially important during the more deadly Delta virus wave during the earlier stage of the pandemic, but it still extends into the Omicron era, which fortunately is not as deadly as Delta was, but still is not to be taken lightly. People are still dying from the virus.

How does politics come into this?

A 2022 study published in the journal, Lancet Regional Health-Americas, found higher COVID mortality rates in more conservative congressional districts across the US. And in another 2022 study using 2020 presidential election returns, researchers at the University of Maryland and the University of California at Irvine found that, through October 2021, Republican-majority counties across the US experienced nearly 73 additional COVID deaths per 100,000 people relative to majority Democratic counties.

These are correlations looking for a cause. A good causal candidate could be differences in vaccination rates between people who tend toward conservatism vs liberalism. The former are much less likely to get vaccinated than their left leaning neighbors. But, that connection needs to be made.

Sure enough, a July 2023 report by Yale researchers in the journal, JAMA Internal Medicine, compared COVID death rates in counties in Florida and Ohio that voted for Trump vs Biden before and after the vaccines came out. The bottom line was that after the vaccines rolled out, Trump voting counties saw 40% higher fatality rates per million residents. Before the vaccines, the COVID death rates were the same for all counties. Viral infection rates were similar for both types of counties throughout the period of analysis. Importantly, counties and individuals that went for Trump had lower vax rates than those that went for Biden.

That pretty much closes the circle on the causation. The greater reluctance of more conservative people to get vaccinated and boosted likely killed them at a greater rate.

Karma?

Now, don’t get me started on the conservative vs liberal attitudes on face masks and social distancing. Conservatives are wrong on these matters. I say this as a conservative myself. But, I also am a data driven scientist who believes data trumps partisanship.

How do you think SARS and MERS were stopped without a vaccine or anti-viral drugs? How do you think society stopped any epidemic such as small pox, influenza, bubonic plague, etc. throughout its history before modern medicine and effective vaccines? How do you think today we are handling Ebola for which there is no vaccine or drug? Non-pharmaceutical physical measures, like masks, gloves, sanitation, social distancing, etc. are effective ways to halt infectious diseases in lieu of vaccine and drug preventive measures.

Conservative resistance to these non-pharmaceutical physical protective measures also probably contributed to their higher death rates observed in the studies mentioned above.

Karma.

Part 3: Gain-Of-Function Research At The Wuhan Lab—Are The Chinese Hiding Something About The Lab?

This is a re-post of a blog, but with additional material. I added new information about the Chinese government response to the first SARS epidemic. You can find that section two-thirds of the way through the post under the headline in bold "The Chinese have done this before:"

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

Yeah, I know, I said this would be a two-blog series about the research at the Wuhan Labs. But a comment a reader made on my second blog post made me think that I should make a third post to briefly address the apparent secrecy and lack of cooperation from the Chinese government regarding the research at the Wuhan Institute of Virology (WIV).

The Chinese have failed to cooperate to help us find the origin of the SARS-CoV-2 virus that caused COVID. They have denied access to WIV lab records or research personnel beyond what was posted on their coronavirus database as I mentioned in my prior blog post. This secrecy and lack of cooperation began in early January 2020 immediately after Chinese officials realized that they had a coronavirus superspreader event at the Wuhan wet market as I described almost three years ago in these pages.

This apparent secrecy on the part of the Chinese has led many people to jump to the conclusion that the Chinese are hiding something sinister—sinister like they secretly created SARS-CoV-2 and accidentally released it and don’t want the world to find out. But, as I have posted several times in these pages, most recently here, there is precious little evidence that supports the notion that the virus came out of a lab. On the other hand, there are several pieces of consistent, but still circumstantial evidence for its natural origin. However, that conclusion is not definitive and could change with new evidence. Hence, we cannot say with certainty that we know where the virus came from. But, remember, it took 14 years and a LOT of work to learn the origin of the virus that caused the first SARS outbreak; it took much longer to discover the source of HIV, and we still do not know where the Ebola virus came from. These things are very hard to learn and take time to figure out.

However, I don’t believe that the best explanation for the Chinese lack of cooperation is that they are hiding something sinister from the world because it seems very unlikely that the virus was man-made. After all, we have several examples of novel coronaviruses popping up in animals and humans, and all have had natural origins. And as I described in my prior post in this series, it is next to impossible that the virus was accidentally released from the Wuhan labs since they really did not work live viruses at all. I think one of two other explanations for Chinese intransigence is more plausible.

The least likely alternative explanation is that WIV lab safety protocols for handling dangerous pathogens were substandard and for the Chinese to allow access to lab records would reveal to the world how careless they were. Perhaps they were concerned about their world image and did not want to be embarrassed. It could deleteriously affect their R&D collaborations with other countries. But, we already had an idea that their safety protocols were not up to Western standards so this would not have been a terribly shocking revelation. That is why I don’t think this is the most likely explanation for the lack of cooperation and transparency.

More likely, however, I think the lack of cooperation probably reflects the general and significant deterioration in science and technology collaboration between China and the US that has been going on for five years. This was the topic of a long article in the Wall Street Journal just a few days ago. In fact, US-China science and tech cooperation has gotten so bad in recent years that US lawmakers are pushing to let a long-standing agreement between the two counties to cooperate broadly on science and technology lapse. It was originally signed in 1979 and renewed every five years since, but will expire this month if not renewed as several lawmakers are pushing.

A once highly productive cooperative science and technology agreement between the US and China seems to have begun falling apart in 2018, before COVID, according to the WSJ article. That is when the US DoJ launched its China Initiative to ferret out Chinese economic espionage. Over time the program increasingly focused on interactions between US universities and Chinese institutions. NIH also launched hundreds of investigations into ties between US science and China. While all these investigations largely failed to turn up criminal conduct, they understandably put a major damper on further cooperation between China and the US. They also led to an exodus of Chinese scientists from American labs. Given all that, it is not surprising that Chinese officials are not opening the doors and books of the Wuhan labs to us.

Thus, this lack of cooperation regarding access to the Wuhan labs is happening as cooperation is seriously deteriorating across the scientific spectrum, not just at the Wuhan labs.

The Chinese have done this before: The Communist Chinese government also has a long history of invoking repressive secrecy in order to prevent itself from looking bad. For example, they also clammed up during the first SARS outbreak back in November 2002 and it threw the country into its worst political crisis since the 1989 Tienanmen Square uprising. The government’s first response to the emerging epidemic was to hide the outbreak from its people, and even from its own public health officers. Despite the cloak of a news blackout, SARS spread throughout the country, reaching Beijing that March (viruses don’t read the newspapers!). But doctors do, and the cloak worked on them. Because of all the secrecy, they were caught by surprise by the sudden and prolific appearance of a new disease, and only learned what was going on via surreptitious text messaging.

In April, WHO officials finally were allowed into the country to inspect Beijing hospitals in order to assess what was going on, but sick patients were shuttled out of the hospitals in ambulances to different hospitals or checked into hotels to hide them from inspectors. Because Beijing tried to hide all this from the world, the epidemic, which might have been limited to that city, found its way into 32 countries around the world (viruses are very slippery). Fortunately, those other countries were not as furtive and were able to nip their infections in the bud with public health measures such as quarantines, contact tracings and isolation, and public closings.

SARS allowed the world to see and compare how repressive and self-sensitive China vs other world countries handle a deadly contagion. China was afraid of losing face and tried to hide its problem from public exposure. However, this backfired and showed China to be a repressive country that was willing to risk the safety of its people and the world in order to avoid accountability for the first SARS outbreak.

Therefore, it is not terribly surprising that the Chinese government again is using repressive means to avoid being put into a position of accountability for the second SARS outbreak.

The bottom line is that to think the Chinese are hiding something nefarious and conspiratorial at the WIV is pure speculation and is backed by no evidence at all. So far. There are alternative explanations for the lack of cooperation by the Chinese that are more feasible and reasonable to believe at this point. New information could change this assessment of course, but evidence that the Chinese are hiding something is lacking. Too bad they won't let us confirm that.

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

Part 2: Gain-Of-Function Research At The Wuhan Lab—What Exactly Was The Wuhan Lab Doing With Coronaviruses?

“I’m just a soul whose intentions are good; Oh Lord, please don’t let me be misunderstood.”  —The Animals

In the first part of this two-part blog series, I described what gain-of-function research entails in order to set the stage for this blog post which describes the coronavirus research that went on in the Wuhan labs. So, was it dangerous and risky? Did it likely lead to the release of SARS-CoV-2 that caused COVID? Let me try to clarify all that now.

Coronavirus research at the Wuhan lab: After the first SARS epidemic in China in 2002, the Wuhan Institute of Virology (WIV) had established itself as a world class coronavirus research lab. It was from their diligent work that the world learned that the first SARS virus came from a horseshoe bat via other animals such as civets and raccoon dogs. That was the result of years of arduous research trudging through bat guano muck in hundreds of caves throughout China to collect samples from thousands of bats. They reported their finding 14 years after SARS appeared and shortly after another strange, lethal flu popped up in the Middle East that was soon attributed to yet another bat-borne coronavirus that came via camel intermediate hosts—MERS.

Before these two coronaviruses that jumped from animals to cause significant disease in humans, the viruses were only known to cause mild human maladies; basically, the common cold. Therefore, when it was learned that the deadly SARS and MERS diseases were caused by coronaviruses, it rattled the cages of health experts around the world. This was brand new!

Hence, even before COVID struck, bat-born coronaviruses were hot on the radars of infectious disease nerds and public health worrywarts. The WIV, as one of the world’s preeminent labs for identifying novel coronaviruses was given international funds to continue their efforts to identify and catalog bat coronaviruses. As they did years earlier when they identified the origin of the SARS virus in horseshoe bats, WIV scientists traveled to far-flung Chinese caves to collect bat guano and biological samples (blood, saliva, fecal) from captured bats. The samples were brought back to the lab in Wuhan for analysis.

Since it is exceedingly difficult and potentially very dangerous to grow wild viruses from such samples (failure is the norm even when many viruses are present in the samples) the lab resorted to their previous tried and true methods of searching the samples for viral genome sequences. They found a LOT of new ones!

Their first and primary order of business in this research was the very mundane task to sequence and catalog all the different coronaviruses they found. They then colligated these genomes into trees of different virus families and posted all the data in a vast database for world scientists to use. They were coronavirus genealogists.

The database is an enormously useful research tool for scientists around the world studying the origins and evolution of coronaviruses in animals and humans. (Coronaviruses also cause significant animal disease, so they also are of great agricultural interest around the world.)

The Wuhan lab also was charged with predicting which of the new virus sequences they found might pose future health threats to humans.

This is where all the controversy begins.

Remember that the Wuhan scientists actually did not have these viruses on hand, just their genome sequences. So, without the actual virus, how could they evaluate the ability of new coronaviruses to infect humans? To do this WIV scientist, Zhengli Shi, used a genetic engineering technique first published in 2015 by Univ. of North Carolina Scientist Ralph Baric to study coronaviruses from their genome sequences (she was a collaborator on Baric’s 2015 paper, so was quite familiar with the approach). It was a technique that also was in use at the time by several labs around the world. It is notable that NIH funded this coronavirus research conducted by Baric at UNC well before COVID appeared and didn’t consider it to be GoF research then.

Using Baric’s genetic engineering technique, Shi’s lab at the WIV used as a tool, a benign coronavirus that they could grow in the lab that was only distantly related to the first SARS virus, but was not known to cause human disease. Its genome sequence was not at all related to SARS-CoV-2 that caused COVID, and which had not yet appeared.

Shi’s lab removed the spike protein gene sequence from the genome of this benign lab virus tool and methodically replaced it with spike protein sequences from each new virus they sequenced. They then grew the lab virus tool carrying the new spike protein and tested its ability to infect human cells in tissue culture.

It is the spike protein that determines whether a coronavirus can infect human cells. Therefore, if the chimeric lab virus carrying the new spike gene infected human cells, it would indicate that the virus the spike protein sequence came from was a likely human pathogen and that virus sequence was then listed on the database as a potential human risk. However, if the chimeric test virus failed to infect the human tissue culture cells, that meant that the spike protein from the new virus genome would not support infection of human cells and the new virus sequence was not categorized as a concern for human infection.

This is how newly identified coronavirus sequences were categorized as potential human health threats without ever having to grow or isolate each virus itself.

In other words, this test simply expressed the spike protein of each novel coronavirus on the backbone of the safe lab virus genome in order to see if it could infect human cells. This completely negated the need to grow and handle the potentially much more dangerous wild-type virus.

It is important to notice that this strategy eliminated all risk of a lab leak of any dangerous virus since it was not necessary to grow or handle potentially dangerous wild-type viruses using this technique.

Is this gain-of-function-research? Strictly speaking, no. Remember, this sort of coronavirus engineering research had been done years earlier in Baric’s UNC lab, and was being done in other labs around the world, and it was never regarded as GoF research then by NIH.

NIH considers GoF research on pathogens to be research that either: 1) increases the pathogenicity of a microbe (that is, makes its disease worse), 2) improves its transmissibility or its ability to infect hosts, or 3) alters the host range of a pathogen. Therefore, in the WIV experiments to assess the ability of novel virus genome sequences to infect human cells, the chimeric test viruses that simply expressed new spike proteins on a laboratory virus backbone either retained the ability of the original lab virus to infect human cells, or they lost the ability to infect human cells.

Therefore, the chimeric viruses gained no new function that was tested. They either retained or lost the ability to infect human cells. The experiments were not at all designed to give the test virus any new functions. Furthermore, these experiments could not have led to the development of SARS-CoV-2 that caused the COVID pandemic, even by accident, since the laboratory test virus used to create the chimeric viruses in the experiments was not at all related to the SARS-CoV-2 virus.

There is a devil in the details: But. Notice that one of the the NIH definitions of GoF research is research that alters a pathogen’s host range. For example, take a flu virus that only passes between birds; avian flu. If you make changes in its genome so that the birds can also pass it to humans that mutation alters its host range and is a GoF change.

In the WIV lab, viruses with new spike protein gene sequences were only tested for their ability to infect human cells in a petri dish. The ability of these chimeric viruses with new spike proteins to also infect other animals was not tested. Theoretically, the chimeric test viruses could feasibly also infect, say a water buffalo, or a wart hog, or some other animal that the original lab virus might not have been able to. That would be a technical gain-of-function. But, that begs the question; in such an experiment, how would you know whether or not the host range of the chimeric virus had changed until you possibly had tested its ability to infect every known animal? A logistical impossibility.

Therefore, based on this theoretical point, it cannot be definitely stated that the experiments were not GoF experiments. In fact, chances are pretty good that some of the novel spike protein sequences attached to the lab test virus in fact altered its host range and, thus, the experiments would technically be GoF research.

Bottom line: Technically speaking, therefore, these experiments carried out at the WIV probably could be called GoF experiments. By a lawyer. Not by a scientist. That picks the proverbial nit and splits a very fine frog hair, to mix metaphors. The same research had been done ten years earlier in Ralph Baric’s UNC lab and was not considered GoF then. What is important is that the research at the UNC or the WIV never set out to create viruses with enhanced virulence, transmissibility, or altered host range. That was never the intent. The aim of the WIV research was solely to predict the human risk posed by novel coronaviruses without actually having to directly work with the potentially dangerous pathogens. Actually working with the dangerous viruses would have posed a very real risk.

Bottom, bottom line: The research conducted at the WIV was the most safe and responsible way to identify new coronaviruses that could potentially pose future human health risks. It is to the detriment of human health that this research has come under heavy criticism and that such future research has been hampered by criticism from people who fail to understand what the research is about and have, therefore, demonized it and want to prevent it.

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

While SARS-CoV-2 And Our Immune Systems Do A Dance, We Get Re-Infected

Note: Artificial intelligence wrote nary a word of the following article, which was fully composed by the natural intelligence of a certain human.

Your sometimes humble blogger remembers how immunology science first beguiled him. It was during senior year in high school in the Virginia suburbs of Washington, DC. More specifically it was during a lunch break while working at a People’s Drug Store that had a lunch counter. Your then nascent blogger grabbed the recent issue of Scientific American from the magazine rack and opened it to an article that was way above his green scientific understanding but, he, nevertheless, gleaned from the article that the immune system could make antibodies to just about any molecule in the universe, even ones newly created in a lab that the universe had never seen. Amazing!

Your immune system would also make antibodies against the cells and tissues of your best friend and everyone else in the world, and vice versa, but you and your best friend, et al., would not make antibodies against the same cells and molecules in your own bodies! What?

“Holy cow!” I thought. How in the world can the immune system do all that? How can it respond to something the world had never seen and secern friend from foe? At that moment, at that lunch counter over a burger, Coke and an article I barely understood, an immunologist was made. And I did indeed go on to earn a PhD in immunology and I indeed have studied how the immune system recognizes viruses and have done vaccine research. What a pivotal lunch break that was for me.

The question about antibody discrimination clearly fascinated me. That mystery has been solved and a few Nobel prizes awarded for its elegant solution, but related spin-off questions about how antibodies protect us keep coming up in different ways. It did so most recently during the COVID pandemic. Why weren’t the antibodies we generated via vaccination or via natural infection more protective against subsequent infection? In a twist in the plot of biology, it turns out that we have learned that the answers to these questions center around a complicated dance performed between both the virus and immune biological systems.

Biology is so doggone interesting!!

COVID Vaccine generated immunity: The several vaccines we now have against the SARS-CoV-2 virus are effective and provide examples of how vaccines are very good at getting the immune system to respond to what it detects as foreign invaders. But the vaccines are just designed to tell our immune systems to make antibodies against just a very small fragment of the spike protein. In contrast, the virus is constructed of several large proteins each of which has many different regions that the immune system can separately recognize as foreign. In other words, if the virus is like a brick building, your system theoretically can make a different antibody that specifically recognizes each brick of the building. So, the vaccine is like exposing the immune system to about 2-3 bricks of the whole building and trusting the resulting immune response against those few bricks to bring the whole building down.

The immune system was very good in generating antibodies to a small portion of the virus, yet many vaccinated people still were infected and caught COVID. Does that mean, as many vax naysayers claim that the vaccines were ineffective? Not at all, as I have discussed here before. While the CoV-2 vaccines did a good job at protecting against serious disease and death they were not very good at preventing the spread of the virus. These vaccines effectively generated a systemic immune response, meaning that you had anti-viral antibodies circulating in your blood, which did do a very good job preventing serious disease once the virus got inside you. But, it still got inside. You still got infected and got mildly sick.

We now know that the virus enters via mucous membranes in your nose, sinuses, mouth, throat and eyes. It has to first cross mucous membranes in order to infect you and that is where it needs to be stopped in order to actually prevent infection and further spread to others. The problem is that mucosal immunity is caused by a different type of antibody than what circulates in the blood and by what is generated by a typical vaccine that is given by an injection in the arm. To generate mucosal immunity, you need a vaccine that you spray in your mouth or nose, which then should generate the type of antibodies that provide mucosal protection and better protect you from infection via that route and better prevent the virus from spreading through a population.

At the beginning of the pandemic, we were faced with a brand new pathogen for which we knew nothing about how it behaved or how it infected and spread between people. At that point, we reasonably chose to quickly make the most common type of vaccine--a shot. While it didn’t fully protect against getting infected, it nevertheless was very effective at protecting against serious disease. So, it did a good job. Current efforts are underway to develop a mucosal vaccine. But, we must also deal with other complications we have learned about the dance between the virus and the immune system to make sure that vaccine will be maximally effective at preventing infection. Read on.

“Natural” COVID immunity: As it became clear that vaccinated people were still getting infected, the vaccine dissenters and dissemblers proclaimed loudly, and still do, that the vaxes failed miserably. They ignored the survival data and only focused on the infection data. They then began touting “natural immunity,” which is the immunity one usually gains after being naturally infected. But, that can be uncertain given the fact that the route of infection and the dose of virus can vary wildly and confer different levels of protection, as I reported earlier. Plus, with natural infection, one runs the risk of serious disease and death from the disease.

Then, to the chagrin of the “natural immunity” enthusiasts it turned out that they also were getting re-infected! And this re-infection occurs despite the fact that natural immunity occurs after infection across the mucous membranes that should, as discussed above, generate an immune response that would stop an infection! This is the dance.

Therefore, we now know that neither vaccine immunity, nor infection immunity fully protects against future infection with the CoV-2 virus (there is partial protection, but I won’t go into that here).

As we learned as recently as last April, from a Harvard study published in the journal Science, despite the fact that a natural infection presents the immune system with the full viral “building and all its bricks” potentially recognizable by antibodies, it turns out that only a few of the “bricks” are in fact actively “seen” at any time by the immune system.

This immuno-dominance of a small part of a larger pathogen that has thousands of sites or bricks the immune system can recognize is not unusual. It is like a large building consisting of thousands of bricks, but having a very attractive window that draws your attention. While you know an entire building is there, your attention is mostly drawn to the window. So can the focus of the immune system be preferentially drawn to a small part of a larger edifice. The immune system is perfectly capable of seeing the rest of the “building,” but it prefers to direct its attention to a small part of it. However, if you take away the part it prefers to focus on, the immune system will easily recognize something else. This immuno-dominance in what the immune system “sees” has several causes that are way too complicated to go into here without writing a textbook (an interested reader might try Paul’s Fundamental Immunology. My rather old edition of that book runs about 1500 pages!). Suffice it to just know that this sort of immuno-dominance often happens where only a small part of a large pathogen is preferentially recognized by the immune system.

Thus, the immunity developed after a natural infection is mostly only directed at a small portion of the virus, much like the antibody response after vaccination with just a small part of the virus. The natural immune response, like the vaccine immune response, is robust and effective, yet both are only directed against a very small portion of a big pathogen, and both are very leaky in that one can still get infected again! What gives?

Mutation gives.

How the virus escapes immunity: The SARS-CoV-2 virus is highly mutable unlike the other viruses like polio and small pox we vaccinate against and maintain long term immunity against. Thus, the virus quickly mutated, or changed, the “bricks” against which the vaccines were made rendering the immune response less and less effective over time as new viral iterations appeared. That is why the many boosters we got were necessary to keep vaccination immunity up with viral changes.

And that also is how someone who became immune after natural infection also became re-infected. The virus did a two-step and mutated the small region recognized by the immune system. It was pretty easy for the virus to do since it only had to change a couple of “bricks” in its facade that the antibodies were mostly attacking. That means that upon re-infection with a slightly mutated virus, the immune systems have to be re-educated to recognize a new intruder, and that takes time, which allows a new infection to settle in. Thus, in this dance, the gentleman virus leads and the dame immune system follows.

New vaccines continue to be developed that scientists hope will solve these problems unique to SARS-CoV-2. Most of the new vaccines are being built on the mRNA platform, but using novel approaches to 1) develop vaccines that can be given as a nasal spray in order to generate the mucosal immunity that hopefully would be more effective at actually preventing COVID. If this works, it might even be possible to hinder COVID spread. 2) But in order to block CoV-2 spread on a population level, we need to find other regions of the virus that are not so highly mutable. These would conceivably be regions of COVID proteins critical for viral function that tolerate little change in structure because that change would destroy the proteins' critical function and essentially kill the virus. Alternatively, new vaccines could incorporate multiple "bricksl" from different regions of the edifice assuming that it would be nigh impossible for all those sites to simultaneously mutate. If such regions are accessible to the immune system, then the resulting immunity would be expected to be impervious to viral mutation, thus ending the dance on a sour note.

It is even possible that such a vaccine could protect against a wide range of coronaviruses, thereby preventing future health problems arising from new coronaviruses. Remember SARS that also popped up in China a couple of decades ago? That virus has some genome similarity to the virus that caused the COVID pandemic, and both are distantly related to the virus that caused MERS that arose in the Middle East. If a pan-coronavirus vaccine can be developed, it could feasibly prevent many future epidemics and pandemics.

We shall see.

This is all part of a new biology that I earlier dubbed BioX. Biology is so doggone interesting!!

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

The Virus Came From Wuhan Lab DOE Now Says…..Sort Of

 “Where’s the beef?” Clara Peller in a 1984 Wendy’s commercial

So, the world has been abuzz since the Department of Energy recently reported that it decided, albeit with low confidence, that the SARS-CoV-2 virus might have leaked by accident from the virology lab in Wuhan. Across cable television and the internet, including sources such as Fox, Breitbart, Joe Rogan, gossip lines, et al., are full of “I knew it all along,” and “I told you so’s.” Never have so many virology experts suddenly been spawned on Facebook. And most of them could not tell you whether a coronavirus is an RNA or DNA virus, let alone the difference between RNA and DNA.

But let’s slow down a bit. Have you even wondered why the Department of Energy is releasing an assessment about a virus? And did you wonder what data they based their assessment on? I did and I explain it here. What I learned tells a much more complete, and less compelling story than what most of the priests of the press, Junior virologists, and other rumor mongers have reported. What has been reported has been woefully inadequate and vastly misleading.

The DOE report was based on intelligence data that remains classified, and is not a science report. Apparently intel spooks weigh science information much differently than scientists do, and often put less credibility in published science because the information usually does not come from “trusted” sources that an spook has history with (their version of "peer review" I guess). The US intelligence community is distributed between 18 agencies, including Energy, State, Treasury, and others including, of course, the CIA, FBI, and DOD. Eight of these entities have been involved in reviewing the COVID-origins issue.

In 2121, the Energy Department, which oversees 17 national laboratories, several of which study SARS-CoV-2 and its origins, reported it was undecided on how the virus emerged. What caused DOE to recently change their assessment is not known. They are not releasing the classified data. Therefore, their information appears not to be scientific data, which is usually published. Four other unnamed agencies, along with a national intelligence panel, still judge that the virus was likely the result of a natural transmission from an animal to humans, and two other agencies are undecided. Only the FBI agrees with DOE in thinking that the virus leaked from the lab. Notably, the CIA also remains undecided. In other words, the DOE’s opinion is a minority opinion of low confidence in the intel community. It is hardly worth all the breathless excitement it elicited from Tucker Carlson and other bloviators who now dishonestly insinuate that it has now been proven the virus came from the lab. That is far from decided.  

The intel community’s definition of low confidence intelligence is “that the information’s credibility and/or plausibility is uncertain, that the information is too fragmented or poorly corroborated to make solid analytical inferences, or that reliability of the sources is questionable.”  Someone should send that to Tucker.

The origin of the virus has been actively investigated over the last couple of years and your sometimes humble correspondent has reported previously on those investigations in these pages (it is worth reading for background). These blog posts have favored the natural origin of the virus, because that is what the preponderance of data have suggested. There have been no published data supporting a lab leak hypothesis. None. Also, recent science reports in top-flight science journals continue to conclude that the virus had a natural origin. A paper just published in 2023 in Cell reported that SARS-CoV-2 is the ninth known coronavirus to have jumped from an animal into humans. Two earlier reports in Science, and also summarized in these pages last March, agreed that the virus originated in the Wuhan wet market not just once, but twice. These studies included genetic evidence and epidemiological tracing showing that the early cases of COVID all centered around the Wuhan wet market and not around the lab eight miles away.

Furthermore, back in 2020, I also wrote a summary of how the earliest events of the pandemic unfolded. Here is a synopsis of the first few days: On December 31, 2019, Chinese officials informed the WHO about a cluster of 41 patients with a mysterious pneumonia in the city of Wuhan associated with a new coronavirus. Then, in the middle of that night a Chinese CDC team from Beijing arrived and collected 585 “environment” samples from a garbage truck, drains and sewers in the wet market. Thirty-three of the samples tested positive for the new coronavirus. Fourteen of the positive samples were from the area of the market where wildlife was traded. At the same time, Wuhan officials quietly began disinfecting the market, and it was closed.

It is interesting that the immediate focus was on the market and not the lab.

Keep in mind that we have very many examples of viruses, including several other coronaviruses similar to SARS-CoV-2, spontaneously passing from animals to cause disease in humans. This includes the first example of SARS-CoV-1 that came from a food market in China in 2002, and then MERS, which passed from a camel to humans. It was natural for medical scientists to first think that SARS-CoV-2 arose similarly. So far, the evidence is not convincing that it did not. The fact that we have not yet convincingly identified an animal source for the virus is not surprising. It took 30 years to establish the source of the HIV virus, and we still do not know the source of the Ebola virus.

So far, despite the very weak statement from the DOE, the preponderance of data still favors a natural origin of the virus, not a lab origin. But, that still is far from definitive. That “preponderance” of evidence, can change in a hurry with new data. Therefore, it remains worth further investigation. But until the Chinese government allows outside scientists to review lab data books and interview scientists from the Wuhan labs, the investigation will proceed with one hand tied behind its back. It remains remotely possible that an animal carrying the ancestral coronavirus will be caught confirming that it did come from an animal. Yet, even if we did find an animal source for the virus, it may not tell us about the path it took to get into humans. We might never know that to the delight of the conspiracy nuts and fabulists out there who have never weaned off the teat of fantasy.

Note: In order to have blog updates delivered to your email, see the very simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

Why Don’t The COVID Vaccines Last Longer?

The FDA just authorized a second booster shot of the Pfizer-BioNTech and Moderna coronavirus vaccines for people over 50 and the CDC has approved it. A second booster has already been approved in the U.K., Sweden, Israel and Denmark.

Why do we need a second booster only months after the first booster, which came only months after most of us received two jabs of either the Pfizer-BioNTech or Moderna mRNA vaccines? Are the vaccines not very good? After all, we get small pox or measles shots that last a lifetime. Others, like the vax for tetanus, last for ~10 years. Why can’t we get a more durable coronavirus vaccine?

The answer is complicated and largely rooted in both viral biology and vaccine immunology.

Viral biology. The simplest answer is that viral mutation can change the molecules the vaccine immune response is trained to recognize, causing vax immunity to decay as viruses mutate. The coronavirus vaccines are directed against the spike protein expressed on the original CoV-2 that first appeared in Wuhan, but that ancestral bug has spawned mutated progeny that look a bit different to the immune system. In other words, viral variants created by “antigenic drift” become less recognizable to the immune system. That is why the vaccines are somewhat less effective against the Omicron variant that carries numerous point mutations in its spike protein. The current vaccines are still pretty effective against current viral variants, but continued antigenic drift along with the selection of variants that can better avoid vaccine immunity will likely require new vaccines in the future.

So, why do we need new flu vaccines every year, and need frequent CoV-2 vaccines, but we don’t similarly need new measles vaccines? Measles, mumps, flu, COVID, and other diseases are caused by viruses, but the different viruses behave quite differently. Viruses carry relatively little genetic material that tends to mutate as they replicate and spread. Some viruses, like flu, also have a “segmented genome” meaning that their genetic material is carried on several separate genetic molecules, making it easy to shuffle their genomes like a deck of cards when different flu strains infect the same animal. Other pathogens carry all their genetic material on a single DNA or RNA molecule making such gene shuffling between strains less likely, but it still happens. Also, the mutation rate of a pathogen’s genome is a function of its replication rate; hence, each time a bug copies its genome, small random errors are inserted into its genetic code. The more the bug replicates, the more mutations will accumulate in its genome and the faster replicating bugs will more rapidly create new variants. Thus, the measles virus is pretty stable since it does not replicate as much as a coronavirus or a flu virus, so it is not surprising that vaccine immunity to measles is much more durable. Smallpox and polioviruses also have relatively low replication rates and vaccine immunity to them also is long-lasting. In contrast, flu and coronaviruses replicate rapidly and pass back and forth between humans and animals. This means that they mutate rapidly and need frequent vaccine updates.

Other vaccines, such as the TB vax, target bacteria not viruses. Bacteria carry larger genomes that are not so changeable, so anti-bacteria vaccines also are pretty long-lasting compared to many anti-viral vaccines.

Yet other vaccines, such as those against tetanus, diphtheria, and pertussis do not even target the pathogen at all, but target toxins produced by the bugs. Vaccinated people produce antibodies that neutralize the toxins and this prevents disease. These vaccines do not forestall infection, they simply prevent the ill effects of the pathogen. Therefore, for these toxoid vaccines, there is no immunological selective pressure to select pathogen variants that can avoid vax immunity. Vaccines against these toxins also tend to be among the longest-lived vaccines.

Vaccine immunology. Vaccines aim to mimic natural immunity we develop to infection with pathogens. By exposing the body to harmless imitations of a pathogen, vaccines create an immune response and immune memory against pathogens, while avoiding the disease caused by the bugs. When an infection does occur in a vaccinated person, a rapid and robust immune response is mounted, first with B-cell generated antibodies that latch onto the invaders and prevent them from spreading and causing illness. Then T-cells secret cytokines that further ramp up the inflammatory response, and other T cells attack pathogen-infected cells. As explained earlier in these pages, antibody responses tend to linger only a few weeks to a few months and then gradually decay. This is good; otherwise your blood serum would be like syrup from all the antibodies against all foreign things you encountered over your lifetime. While antibodies circulating in your blood are good for quickly attacking infections shortly after infection, they do not confer long-term immunity. What confers long-term protection is what are called memory cells. These are a relatively few T and B cells that go dormant after fighting an initial infection or responding to a vaccine, but hang around awaiting a new infection to signal them to quickly roar back to life and mount a vigorous response against their cognate pathogen. This secondary response to a previously seen pathogen is much faster and usually nips the bug in the bud so you don’t even know you were infected.

When we hear that CoV-2 immunity decays only a few months after vaccination, the reports usually refer to declining levels of anti-CoV-2 antibodies, which happens naturally. Such announcements do not take into account your immune memory, which is harder to measure, but which is a better metric of your long term immunity. The problem also is that we simply have not had enough time with the vaccines to know how long their immune memory persists. It seems relevant that a study published in July 2020 reported that people who were infected with SARS in 2003 maintained robust T cell immunity 17 years later. So far, indications are that even though antibody levels fall over time, immunological memory after vaccination also remains robust. This is seen by the continued protection from serious disease and death in vaccinated people with low antibody levels. The vaccines and the immune memory they stimulate are working. How long that memory persists is unknown. Time will tell.

So why are we getting the booster shots? In the face of a raging pandemic caused by a novel pathogen, the cautious approach is to keep antibody levels at a protective level in vaccinated people until we better understand the extent of long-term protection brought on by our immune memory. The boosters, therefore, represent a cautious approach to maintain an effective antibody defense during these still early months of a novel pandemic. We likely will reach a time where world-wide immunity from vaccination and natural infection will give us baseline protection that will render COVID-19 mostly a bothersome disease rather than a life threatening infection. Until then, the boosters are a good idea to help us maintain an effective antibody defense against serious disease.

The natural pathology of measles is instructive here. Even though antibody levels typically decline after most immunizations, antibodies produced after a measles vaccine persist for many years. This happens with some other, but not all, vaccines too, but why? In countries where the measles virus is endemic, repeated infection of vaccinated people keeps the antibody immune response in continual high gear. That is not the case with the flu virus which changes rapidly and bypasses last years shot. Interestingly, measles has been eradicated from the US and Western Europe, so vaccinated people are not continually exposed and re-exposed to the virus and, unlike for those who live in endemic areas, our anti-measles antibody levels decline. Therefore, our long-term protection against the virus is due to our immune memory and not due to antibody levels.

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

Lions And Tigers And…Deer? Oh My!

First it was bats and humans, then domestic cats and dogs, farmed mink, and big zoo cats; now gorillas, hippos, and wild deer that have been infected by the SARS-CoV-2 (CoV-2 for short) virus. Many of these animals have become ill and several have died of COVID-19, most recently three snow leopards in South Dakota and Nebraska zoos. This is quite a wanton virus.

Of course, before CoV-2 and COVID-19 were known to the world, we knew that bats, humans and a few other animals, notably civets and even camels, were ready hosts of several different strains of “‘rona” viruses. We also knew that domesticated animals are also susceptible to their own coronavirus diseases—in fact veterinary coronavirus vaccines have been in use for years. Humans are known hosts for several coronaviruses, including those that cause the common cold, as well as the viruses that cause SARS, MERS, and now COVID-19. And we know that humans often catch these germs from bats and other intermediate hosts as diverse as civets and camels. After we genetically identified CoV-2 and were able to follow its spread, we quickly noticed that domestic pets also could be infected. This was closely followed with news that seven big cats at the Bronx zoo had become infected, and that mink farms across Europe were hotbeds for CoV-2 spread between humans and the animals and back. In fact, mink farms became such a hotbed of CoV-2 zoonotic spread that a couple of European countries completely shut down mink farming and culled all their animals. Several US states have also sharply curtailed mink farming. PETA probably applauds.

More recently two snow leopards at the Lincoln, NE children’s zoo and one in a zoo in South Dakota died from COVID. The Lincoln zoo also had two infected Sumatran tigers who recovered after being treated with steroids and antibiotics to prevent secondary infections and pneumonia. How the animals were infected is uncertain, but the most likely scenario is that they caught the virus from a caretaker. The problem is, none of the caretakers tested positive for the virus. Bats? Something else?

Since April 2020, when a tiger tested positive at the Bronx Zoo, dozens of other animals in zoos around the world have caught COVID. This month, the Denver Zoo reported the first coronavirus cases in hyenas, and the St. Louis Zoo found eight positive cases among its big cats, including two snow leopards. Abroad, the virus has killed a lion in India and two tiger cubs in Pakistan. Big cats seem especially susceptible since three other snow leopards at the Louisville Zoo were infected last December, and another snow leopard tested positive at the San Diego Zoo in July. The virus doesn’t just infect our fuzzy friends either; two hippos, named Imani and Hermien, at a zoo in Antwerp recently tested positive for COVID-19. Zoo keepers were first alerted to a potential problem when they noticed that the colossi had “runny noses.”  One reckons that a runny nose for a hippo is a big deal. One also wonders who gets to dab that nasal maw in order to test for the virus.

In fact, zoo and domestic animal infections have become so prevalent that an animal COVID vaccine developed by Zoetis, a NJ-based veterinary pharma company and former Pfizer subsidiary, has been authorized by the USDA for experimental use. The Cincinnati Zoo, for one, has vaccinated  80 animals, from giraffes to apes, against COVID.

Deer too. Oh my! It is one thing for zoo animals to acquire COVID—their captivity makes it easy to limit their interaction with other animals and humans to prevent spread of contagions, and they seldom complain that their rights are being infringed when they are quarantined. However, COVID in wild animals is a different story, as we have seen with bats and how easily they transmit the virus to humans. Scientists now have evidence that CoV-2 also readily propagates in white-tailed deer. In fact, the virus is already widespread in cervids across the US, which likely has significant implications for the long-term course of this pandemic.

In September of last year, genetic analysis of the gene that encodes the ACE2 protein (i.e., the viral receptors expressed on many cells in the body) in many different animal species suggested that CoV-2 could easily infect deer (and several other animals too). A survey of white-tailed deer in the Northeast and Midwest found that 40% had antibodies against the CoV-2 virus, indicating prior exposure. Between April and December 2020, veterinarians at Penn State found active CoV-2 infections in ~30% of deer tested across Iowa. Then during the winter COVID surge in humans from Nov. 23, 2020, to Jan. 10 of this year, ~80% of the tested deer were infected. The prevalence of the virus in deer was 50 to 100 times greater than in Iowa residents at the time (and the deer reportedly did not wear face masks). The study, published about two months ago, indicates that white-tailed deer have become a permanent reservoir for CoV-2. While it is not fully understood how the virus entered the deer population, genetic sequence analysis of nearly 100 viral samples found that the variants circulating in deer matched the variants circulating in people. This suggests that deer caught the virus from people multiple times in Iowa alone. How that happens is not known since people usually do not have close contact with live deer. More concerning is whether viral variants arising in deer readily pass back to people.

Bottom line. Clearly, a lot of different animal species can catch Cov-2 and spread it. It is clear that people can spread coronaviruses to pets and other animals, but the FDA says that the reverse, animal-to-human virus transmission, is not common. But, it clearly happens as we have seen with this pandemic, and with many other viruses that cause SARS, MERS, AIDS, Ebola, flu, etc., that spread from animals to humans. The prevalence of CoV-2 infection in so many species of mammals, especially in animals that have close contact with humans, suggests that several animal species, not just bats, can serve as permanent reservoirs for the virus and the jump to humans is something that can happen over and over. This is not unprecedented. It is what we see with influenza, which is carried back and forth between the Northern and Southern hemispheres with migratory birds, in which different flu viruses shuffle their genomes to create the new strains of flu for which we have to vaccinate against each year. This animal reservoir for flu makes it next to impossible to eliminate influenza, and similar animal hosts for CoV-2 likely would make it nigh impossible to eliminate COVID too. I raised this specter some months ago in these pages when reporting that pet dogs and cats can carry the virus. Our furry friends represent a viral reservoir that is in even closer contact with people than bats, deer, and fortunately, hippos and leopards.

We also have to be worried about the CoV-2 virus mutating in the different animal species that harbor and spread it. We know that happens in bats, which makes it almost certain that new strains of the virus will arise in deer and dogs too. We have already seen this on mink farms in the Netherlands and Poland. Farmworkers passed the virus to captive animals where it spread, mutated, and then spilled back into humans. In fact, zoonotic transmission from animals to humans probably happens thousands of times a year. Researchers from the EcoHealth Alliance and from Duke-NUS Medical School in Singapore, estimate that each year many people are newly infected with SARS-related coronaviruses. Many may get sick, but there are many reasons why most of these infections never grow into noticeable outbreaks (for example see my earlier blog post about unusual respiratory infection clusters in China and Los Angeles just before COVID). The researchers also created a detailed map of Asian habitats of 23 bat species known to harbor SARS-related coronaviruses then overlaid it with data on where humans live to create a map of potential infection hot spots. They found that close to 500 million people live in areas where bat-to-human transfer is likely, and this risk is highest in southern China, Vietnam, Cambodia, and Indonesia. Other surveys done before COVID-19 showed that many people in Southeast Asia harbor antibodies against other SARS-related coronaviruses. Blending these data with data on how often people encounter bats and how long antibodies remain in the blood, the researchers calculated that ~400,000 undetected human infections with these viruses occur each year across the region.

That is just for bat-to-human transfer in Southern Asia. It now looks like we will have to also concern ourselves with zoonotic coronavirus transfer from Buddy and Bambi too.

For this reason, researchers are working to develop a universal coronavirus vaccine that will be effective against most viral strains and variants. I will write about this soon. Stay tuned.

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.

The Long Haul, Part 3: Long Neurological COVID

As I have noted before in this series, acute COVID-19 often appears with neurological symptoms ranging from loss of smell to severe depression to stuttering to brain fog, mania and psychosis. It sometimes has been linked to suicidal ideation. In addition, long haulers often have cognitive symptoms and structural brain changes similar to those seen in aging brains and in those with Alzheimer’s disease. An early survey of 153 COVID-19 patients in the UK and a more recent study of people hospitalized with the acute disease in Italy both found that about a third had neurological symptoms of some kind ranging from sensory problems, motor impairment, and cognitive issues that persist after clearing the acute infection. Other estimates of neuro involvement in long COVID have trended even higher. Many people who survived earlier coronavirus infections such as SARS and MERS also experienced neurological impairments up to 3.5 years after acute infection. Obviously many of these symptoms of long COVID are very serious while others are more annoyances. So, what is going on? Researchers have pretty well cataloged the unusual range of long COVID’s neurological symptoms and now are at the very early stages of understanding their causes and how to treat the problems. Here, I label long COVID that primarily manifests itself with neurological symptoms as “long neuro COVID” in order to distinguish it from other long COVID problems that primarily involve the lungs, heart, or other organs.

What is long neuro COVID like? In the early days of the pandemic, a newly minted English MD worked on the front lines in a COVID ward and soon became a patient herself. Being 35 and healthy she expected to quickly recover but underwent the long haul, which she has written about. The acute phase of the disease lasted about two weeks, but by 4-5 weeks, she was experiencing new persistent problems including tachycardia with a resting heart rate of 140 bpm (normal is 60-100) that would increase to 170 after minimal exertion such as getting a glass of water. She also was breathless with a resting respiratory rate of 20-24 (12-16 is normal), saying it felt like her “body forgot to breath.” She described cyclic bouts of pins and needles in all four extremities, and whole-body shaking as violent as if she were having a seizure. There were feelings of impending doom, and, despite extreme mental and physical exhaustion, she was unable to sleep, which eventually led to hallucinations. Those symptoms slowly subsided over a few months only to be replaced by intense pain very deep in one ear. This ultimately led to tinnitus and some hearing loss and a diagnosis of encephalitis. Ten months later, she wrote that  she was recovering but was far from normal. She suspected that these symptoms were driven by a dysfunctional autonomic nervous system, a condition called dysautonomia. The autonomic nervous system is what regulates your organs and allows you to breath, your heart to beat, your gut to move food through it, and controls your blood pressure without you having to think about it all. Since her experience in early 2020, it has been confirmed that long neuro COVID can wreak havoc with both the peripheral and central nervous systems.

 

After two years of long COVID, we now know that long neuro COVID symptoms are wide ranging; some are devastating, like stroke, encephalitis, and even psychosis or mania, or even suicide. Other neuro symptoms are more subtle such as cognitive decline, loss of smell, hearing loss, balance problems, fatigue, memory problems, and difficulty concentrating or brain fog. Others are bizarre, such as stuttering. This seemingly unrelated range of symptoms suggests that there might be several different subtypes of long neuro COVID, possibly arising from distinct pathologies.

Back in July 2020, one of the first studies was published describing neurological symptoms that appeared long after the initial COVID disease. This since has been followed by several other reports of neurological or neuropsychiatric problems long after recovering from acute COVID disease. One study by Oxford scientists published last February, found that about 33% of post-COVID patients are left with long term mental health or neurological symptoms including brain fog, headaches, dizziness, and cognitive problems such as difficulty doing simple math. Some studies have shown an elevated incidence of PTSD, and seizures or movement disorders  long after COVID recovery. Other post-COVID patients have new-onset depression, psychosis, and suicidal behavior as reported in JAMA Psychiatry by a Columbia University research team this past spring. In this large study investigators examined electronic health records of more than 236,000 COVID-19 patients, mostly in the US. The researchers compared their records with records from those who experienced non-COVID respiratory tract infections during the same time frame and found an increased incidence in anxiety and mood disorders in post-COVID patients. More than three months after diagnosis, these common psychiatric diagnoses were found in about 34% of COVID survivors. Other studies confirmed that having the disease led to doubled risk for anxiety, depression and sleep disorders.

Importantly, researchers did not see an increased incidence of other neurological problems such as Parkinson’s disease or Guillain-Barré syndrome in long COVID patients, both of which sometimes follow viral infection. This suggests that long neuro COVID involves a select subset of neurological problems rather than an indiscriminate neurological malady.

Similarities between long COVID and Alzheimer’s disease. The cognitive issues seen in many long neuro COVID patients share intriguing similarities with Alzheimer’s disease (AD) and normal aging. Thus, an international group of researchers found that more than half of patients 60 or older who had been infected with the CoV-2 virus showed acceleration of Alzheimer’s-like symptoms such as cognitive decline. Other researchers at the University of Texas Health Science Center, San Antonio studied more than 200 older adults from Argentina who had COVID-19. Those who had a persistent loss of smell were more likely to experience AD-like cognitive issues. Importantly, the area of the brain affected in AD overlaps with the area that processes smell. It also might be relevant that the sense of smell, which is often lost in COVID patients, is also often reduced in AD patients.

Three to six months after they were infected, more than half of these patients still struggled with AD-like cognitive challenges including persistent forgetfulness, difficulty sequencing tasks, and forgetting words and phrases. How sick a patient was with acute COVID-19 was not an indicator of whether they would experience this cognitive decline. In other words, AD-like symptoms also occurred in people who only had mild COVID.

COVID-19, of course begins as a respiratory disease and investigators have long been tuned in to the potential links between respiratory diseases and the brain. For example, AD-like changes in cognition and behavior were also observed in people with Severe Acute Respiratory Syndrome (SARS) and with Middle East Respiratory Syndrome (MERS). Infection with other respiratory viruses can also increase the risk of Alzheimer’s.

Together, these findings suggest that some patients with long neuro COVID might have an acceleration of Alzheimer’s-related symptoms and pathology, but it is too soon to conclude that long neuro COVID causes AD, or even that AD and COVID-related cognitive dysfunction are even related. A major distinction between classical AD and AD-like long COVID is that the latter do not show the amyloid brain plaques which are pathognomonic of AD, which suggests that these could be distinct cognitive maladies with overlapping symptoms. Furthermore, other studies showed that worse cognitive scores in long COVID patients correlated with patients who had lower oxygen saturation during a 6-minute walk test. This makes it possible that persistent oxygen deprivation in the brain due to lung compromise during COVID could cause cognitive difficulties in these patients.

At this point, these observations simply raise many unanswered questions on whether there is a real overlap with COVID and Alzheimer's disease. But, it is too soon to say that COVID-19 increases a person's risk for Alzheimer's vs causes a different neurological problem symptomatically related to AD.

What causes long neuro COVID? Long COVID represents a broad category of over 200, often unrelated symptoms encompassing 10 organ systems. It likely consists of multiple different maladies with manifold causes, of which long neuro COVID is at least one broad category. Based on its biology and range of symptoms, long neuro COVID also likely entails more than one specific problem. It makes sense then that the many different manifestations of long neuro COVID would arise from different causes. Such seems to be the case. Researchers have cataloged several genetic, structural, inflammatory, and infectious correlates to the various symptoms, painting a complicated picture. Then things get really confusing since viral infection of neurological tissues and/or the attendant inflammatory responses could cause the observed structural changes and all this could be predisposed or mitigated by genetics. In other words, things are as clear as mud right now about what causes long neuro COVID. Investigators are just now making basic observational correlates between the neurological changes and long neuro COVID symptoms, and these correlations will be followed by the harder studies to learn just how these changes might cause the plethora of symptoms that have been documented.

On the genetic front, a Stanford U team found that long neuro patients manifest widespread changes in gene expression in the region of the brain involved in complex processing of human thought. These genetic changes affected genetic pathways that play a role in mental illnesses such as schizophrenia and depression. Although these results were made in the brains of patients who died of acute COVID disease, such fundamental changes in gene expression in the brains of patients with acute COVID would plausibly lead to long-lasting post-COVID effects. Similar changes in gene expression were not found in the brains of people who died from flu or from nonviral causes, which strengthens a possible cause and effect relationship of gene expression changes to some long neuro COVID symptoms.

But, what causes changes in brain gene expression? Is it directly due to viral infection in the brain or secondarily due to the immune inflammatory response to the virus? Maybe both? Or is something else involved? Evidence exists for all these possibilities.

One report on 111 unvaccinated patients from the Chicago area showed that 56 who had long neuro COVID cognitive problems showed a particular immunological signature that was not found in people who cleared the acute infection without long term problems. The severity of cognitive deficits correlated with reduced memory T cell responses to certain parts of the virus, and with enhanced antibody (or B cell) responses to one of the viral proteins. Furthermore, it has been observed that females are more prone to devleop long neuro COVID. Since women also are more likely to get autoimmune disease, some have put these observations together to suggest that there might be an autoimmune component to some long neuro COVID symptoms.

The above study assessed the anti-CoV-2 immune responses of T and B cells from the peripheral blood but not from the brains of the patients. In other words, it did not address whether the immune response in the body affects brain function or whether an antiviral immune response directly occurs in the brain affecting cognitive function. Other researchers have shown that the virus can indeed enter the brain via the nose and spread from the olfactory lobe to the frontal and temporal lobes of the brain. Other confirmatory studies have found viral protein expression in cortical neurons of autopsied brain tissues, and have directly shown that the virus can infect neurons in tissue culture. While these findings are consistent with direct infection of the brain and the possibility of immunological damage to the organ, they do not settle the question of whether viral infection itself might directly damage the central nervous system, or whether it is the immune reaction to the virus that causes the problems.

Perhaps confounding all of this are the results of a large study on gross brain structure conducted by researchers at the University of Oxford and at the NIH. In this study, researchers used the UK Biobank, an existing database, which contains brain imaging data from >45,000 people in the UK going back to 2014. This means that there was pre-COVID baseline imaging data the researchers could compare to post-COVID brain images. New images were collected from 394 of these patients who caught COVID and compared to their pre-COVID images and to 388 controls who did not catch COVID-19. The groups were otherwise matched based on age, sex, common disease risk factors, etc. The results showed that those who caught COVID suffered significant loss of gray matter in the frontal and temporal lobes on the left side of the brain. This brain loss was found regardless of COVID disease severity. Those who were COVID-free had no brain tissue loss. Interestingly, these regions of the brain are responsible for smell, taste, memory, and emotion, all of which can be affected in long neuro COVID patients. We also often talk about the left temporal lobe in the context of aging and Alzheimer’s disease because that is where the hippocampus is located, which plays a key role in memory and other cognitive processes associated with aging and AD. While it is normal to see reduction in gray matter with age, the COVID-linked changes were greater than that typically seen during normal aging. All of this raises questions about how COVID might affect the natural aging process in the brain.

In addition to these genetic, immunological, and structural changes in the central nervous system of COVID patients, autopsies also have revealed clotting in multiple organs including the brains of many patients. About one in 50 COVID brains showed evidence for an ischemic stroke, which is when a blood clot interrupts blood flow to a region of the brain downstream from the clot. Ischemic strokes in COVID patients tended to be more severe and more likely to result in severe disability or death than stroke in non-COVID individuals. Again, while these findings were made on autopsies of patients suffering from acute COVID, these ischemic strokes would have caused long term manifestations presenting as long neuro COVID.

There are other, very specific and very peculiar neurological symptoms that might arise from more specific neurological abnormalities. For example, some long COVID patients display hearing loss and or balance problems which suggest vestibular involvement that could be due to CoV-2 infection of the inner ear. Scientists at MIT and Stanford found that the ACE2 protein, which is the cell receptor for the CoV-2 virus, is expressed on certain inner ear cells obtained from surgery patients. Since inner ear tissue is difficult to obtain, the researchers directed stem cells to develop into inner ear cell precursors or that could assemble into primitive inner ear  organoids in tissue culture and showed that the CoV-2 virus could infect them. Together, these observations support, but do not prove, that infection of the inner ear is a cause of hearing and balance issues in some long neuro COVID patients. It is relevant to note that it is not unusual for hearing loss and balance disorders to be caused by other viral infections of the inner ear.

Then there also are the rare long COVID patients who develop an odd stuttering problem. Typically, stuttering originates in the complex circuity of the brain that controls speech and this speech disruption usually appears when children are learning to talk. However, “neurogenic stuttering” can arise in adults after brain trauma. Since only a few researchers are investigating long COVID-associated stutter, the cause is not well understood, but, the link between neurogenic stuttering and brain injury raises the possibility that inflammation and/or micro-clotting caused by the virus or by the immune response to the virus in the brain microvasculature could lead to the neurological damage that causes stuttering.

Bottom line. These many new findings, while provocative, do not yet fully tell us how long neuro COVID arises, or how to treat it. But, they raise many new questions: What do these COVID-related brain changes mean for the process and pace of brain aging in long COVID patients? Over time does the brain recover? How do we medically deal with these patients? Can we prevent long neuro COVID? Etc.

Stay tuned, we will see.

Note: In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want.