Coronavirus news & views

Updated: Over 65? Roll Up Your Sleeve Again

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The Washington Post just reported that Pfizer and its partner-in-vax, BioNTech, plan to seek emergency authorization for a second CoV-2 booster for those of us 65 and older (you know who you are). It is intended to beef up immunity that wanes a bit a few months following the previous booster.

US data show protection against severe COVID illness is robust after the first booster, but falls somewhat from 91 percent effective in preventing severe illness to 78 percent effective over several months. Still, 78% protection is very good, but given how transmissible Omicron is, and the possible emergence of the Son-of-Omicron, which might be even more infectious and virulent, the idea behind a second booster is to offer people the chance to acquire the greatest level of protection possible. Not a bad idea.

The data that will be submitted to the FDA in support of the 2^nd booster probably will include real-world data collected in Israel, which has already rolled out the second shot, and has reduced infections and serious illness in people older than 60. This will likely not be the last CoV-2 vax we will see. Pfizer and BioNTech are also working on a vaccine more effective against all variants and provide more lasting protection. That remains on the horizon, so stay tuned.

For those of us 65 and older, we (at least the males in that demographic) remember draft cards. As we entered our later years, the draft card, if unburned, was replaced in our wallets with our AARP cards, and then accompanied with our Medicare cards. Now we need a new wallet pocket to accommodate our vax card.

On a personal note about cards, your maturing and slowing bloggeur admits favoring a certain grocery store in town because they still card him when he buys his bottles of 80 proof anti-vax remedies.

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Update: Three days after this was first posted, Moderna announced that it also has asked for FDA approval for a second booster. However, they ask that the booster be approved for all adults over 18, and not just for those over 65 as Pfizer/BioNTech have done. This request, like the one submitted by Pfizer/BioNTech is largely based on recent data from Israel. 

Moderna made a strategic decision to request approval for all adults in order to give the FDA flexibility in deciding which patients would be good candidates for the booster. In other words, they could decide that it also would benefit under 65 and so recommend.

 

 

“Mater Artium Necessitas”

So said William Horman, 16^th century Headmaster of the Eton school. Translated, he posited, “The mother of invention is necessity.”

And necessity these days means environmental screening for SARS-CoV-2. Room air samplers have been developed and used to detect airborne virus RNA in large settings, such as hospitals and other large buildings people frequent. In fact active environmental air samplers have been used outdoors to detect airborne DNA and RNA as a way to survey animal populations in the wild. These are fairly large, immobile, active air samplers that require electricity to power them and crews to maintain them. While useful, environmental samplers are limited by their power requirements, lack of mobility, cost, and maintenance needs.

So, the mother of invention led to a portable, passive, personal air sampler that can be worn on one’s collar tool as described in a recent paper. It was reported to be quite effective for detecting ambient exposure to aerosol and droplet CoV-2 in the air.

The device uses a polydimethylsiloxane (PDMS)-based passive air sampler, which previously has been used to capture hydrophobic chemical contaminants and other nonpolar compounds, such as lipid-enveloped viruses that stick to the polymeric surface. After laboratory testing under controlled conditions that determined the unit could detect sub-infectious levels of virus exposure, samplers were passed out to select community members across Connecticut to surveil personal CoV-2 exposure. The study reported that 21% of wearers working in indoor restaurant settings, and 9% working in homeless shelters were exposed to 4-112 copies of CoV-2 per cubic meter of air. No exposure was reported for healthcare workers or “community members” who did not work in putative high-risk environments. The authors surmised that the lack of exposure by healthcare workers was due to the strict sterilization and hygiene procedures used in clinics and hospitals.

While the monitors did a good job sampling ambient air in real time, the need to later analyze the sample by RT-PCR for the presence of viral particles means that the results are not obtained in real time. This is a bit of a drawback to the current personal samplers.

Bottom line. These PDMS-based passive samplers may serve as a useful exposure assessment tool for airborne viral exposure in real-world high-risk settings and allow early detection of potential cases and guidance on infection control. More broadly, this also could be used to monitor the presence of other biological scourges in public places and serve as early warning devices for biological warfare threats.

Necessity is indeed the mother of invention.

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Still More Evidence For An Animal Origin Of The Virus

Conspiracy buffs won’t like this, but compelling new evidence presented in three papers, which include photographic and DNA data, has pretty much nailed down the origin of the SARS-CoV-2 virus. It began in a wet market animal not in the lab eight miles away as the conspiracists have conjectured. This new data comes from an international team of scientists which concluded that the coronavirus twice jumped from  caged wild animals into people at the Huanan Seafood Wholesale Market in Wuhan. These data correlate nicely with previous geo-epidemiological data showing the market, not the lab, to be the infection nidus with later infections radiating out from there.

Despite the Chinese’s government denial that live animals were sold in the Wuhan market, the new studies provide photographic evidence of wild animals sitting in stacked cages in the market in late 2019, in or near stalls where scientists found SARS-CoV-2 virus on a number of surfaces, including on cages, carts and machines that process animals after they are slaughtered at the market. This, along with a new genetic analysis pinpoints a specific stall at the market where the virus passed from an animal into people. These data also estimate the time when not just one but two zoonotic spillovers occurred, once in late November or early December and then again few weeks later. This coincides almost exactly with the timing of the outbreak of disease at and around the market.

The two initial infection events involved slightly different versions of the SARS-CoV-2 virus. The fact that they were related is evidence that the virus had spread and mutated in animals in the market before it infected humans.

A leader of two of the studies was U of Arizona professor, Michael Worobey, a viral pandemic sleuth who has been at the forefront of the search for the origins of the bug responsible for the current pandemic. His lead in the research is significant since, back in May, 2021, Worobey, along with 17 other scientists, called for investigation into the lab-leak theory. His latest research overturned that conjecture. This new evidence adds to previous evidence for an animal/market origin of the virus presented earlier in these pages here and here.

Final thought. It is sobering to think how these two simple infection events that occurred in November and December of 2019 in a Chinese market triggered something that has now caused six million deaths and untold misery around the world. And it is not finished with us.

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Another Unexpected Pandemic Consequence: Undiagnosed Cancer

In these pages, your humble bloggeur (that would be me) has written about several unusual consequences of the COVID-19 pandemic. Most of these were on the ironically funny side, such as farmed fish being too large for restaurant plates, rattlesnakes climbing in plane landing gears, and the ketchup packet shortage. But, not all of these odd aftermaths of the pandemic are humorous. The topic of this post is very unfunny.

It seems that as healthcare providers were swamped with COVID cases, or were at reduced capacity because staff became ill, or because service slowed in order to prevent CoV-2 spread, many people have missed routine medical care for non-COVID problems. It is feared that this will create a crisis in coming years involving increased diagnosis of cancers that were caught later than usual. As we deal with the fourth wave of COVID-19 caused by the Omicron variant, we are learning that the pandemic dramatically disrupted routine health screenings for cancer and other chronic diseases. Some now predict that the next crisis that could overwhelm the US health system will be a surge in advanced chronic diseases like cancer that went undiagnosed and untreated for too long.

Screenings for several major cancers and new cancer diagnoses fell significantly during 2020, according to a study published in December 2021 in the journal Cancer. This was not because there was less cancer in the world. It was because fewer patients were seeing their doctors.

A co-author of the Cancer study, and who is a professor at the University of Maryland School of Medicine, said that we have never before seen screening rates drop so dramatically in such a short time.

In one case, a Hispanic man in his 40s first noticed rectal bleeding in early 2020 that his doctor said was probably due to hemorrhoids. The man was unable to get a timely colonoscopy to rule out cancer because the local hospitals were overwhelmed with COVID-19 patients, and he also feared catching COVID if he went to a hospital swamped with COVID patients. Eighteen months later, he finally got a colonoscopy, which revealed advanced rectal cancer. Those 18 months likely were the difference between being cured by a simple polyp removal vs dealing with a cancer that had metastasized throughout his body.

At this point, nobody knows how many cases like this are out there. We will find out.  

This patient, as thousands of others like him, had the misfortune to notice symptoms that needed followup amid the biggest disruption of medical care in US history. In 2020, while hospitals curtailed services in order to prepare for the COVID surge, the number of colonoscopies plummeted 93 percent. By the end of the year, there had been 133,231 fewer colonoscopies performed compared to 2019. There also were 62,793 fewer chest CT scans, 49,334 fewer fecal blood tests, and prostate biopsies dropped 25%.

This drop in screenings has created a huge backlog that will take months to clear. A gastroenterologist at a small community hospital in the Middle-of-No-Where, Kansas was recruited by a larger hospital in Kansas City to do nothing but colonoscopies from 7 in the morning to “whenever at night.” They had a backlog of 1000 patients—a certain percentage of whom have cancer already growing in their colons while waiting to be told they had colon cancer. And that backlog begets a fresh one of new patients who also need to be scoped because they just noticed something like rectal bleeding, but will have to wait for those who have already been waiting.

This backlog creates a subtle form of medical rationing. It forces doctors to make hard choices about which patients to prioritize. "Lucky" are the serious patients who are moved to the head of the line. Not so lucky are those whose colonoscopies or mammograms or biopsies are then further delayed.

I would rather deal with rattlesnakes in my plane's landing gear or forgo mustard on my brat (which would be pushing the limit) than delay a needed medical test or procedure. It seems that your humble bloggeur (me again) has been caught in the backlog. I am scheduled to have an enlarged parathyroid gland removed next week, but COVID can still derail that. I won’t be certain that the surgery will happen until the day before I am to be operated on and that depends, in part, on everyone, including me, being COVID-free, and the OR not being diverted for use as a COVID ICU. If it proceeds as scheduled, I will have waited several months since the initial diagnosis for the surgery. An additional routine diagnostic test I need in order to determine how the fractious organ might have affected my bone health was scheduled six months out. Six months for a routine scan?

The Long Haul, Part 4: The Cost of Long COVID In Terms Of Individual Health And Quality Of Life

Surviving COVID-19 is one thing, recovering is another.

My frustration with those who would minimize the impact of COVID-19 is reaching an apex. I constantly have to deal with their baseless rationalizations that “it is just a cold,” or “it only kills 0.01% of people” (actually the number is 2% around the world), etc. And I constantly reply to these iconoclasts that COVID has become, by far, the leading killer in the US. I also explain over and over that treating simple mortality percentage as the only relevant statistic to consider is falderal. For example, the Spanish flu also killed “only” 2% of those infected, but in just 24 weeks, that virus killed more people around the world than were killed in WWI AND WWII together! The percent figure is meaningless without considering the percent of what. Why do they continue to ignore the devisor and, hence, the total number of deaths?

A small percentage of a very large number is, in fact, another large number.

Those who wish to downplay the significance of the pandemic only focus on this mortality percent, but mortality is NEVER the whole story for any pandemic. A serious person will also consider the morbidity caused by the disease. In fact, the major CDC publication on health in the US is called the Morbidity and Mortality Weekly Report. Notice that it considers both morbidity and mortality, and further notice that morbidity is listed first in the title. I have made three prior posts in this series on Long COVID, about the significant lasting morbidity of COVID-19. You can see these posts here, here, and here. In those posts, I shared data showing that some ~10-30% of COVID survivors suffer serious health problems that last months.

In those posts, I mentioned the cases of a young, healthy MD, and of a young, healthy journalist, both of whom struggled with long COVID, and how it affected their careers and cost them thousands of dollars in out-of-pocket expenses for the dozens of tests and doctors they needed. In an article in Maclean’s magazine, a reporter interviewed many Canadian long COVID patients and heard how their lives have been turned upside down. They reported that they are unable to live like they used to and care for their families, do anything mildly strenuous, or even cook their meals. They spend long stretches of time in bed. Many of those interviewed had not returned to work several weeks after recovering from the acute disease.

Anecdotes like these have been repeated millions of times around a world that, according to the Johns Hopkins University COVID tracker, has seen more than 330 million cases of COVID (and this is a significant undercount since many countries do not record these data well). Research has corroborated these anecdotes.

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Common long-term symptoms include debilitating fatigue; respiratory problems; and “brain fog.”  Other common symptoms include compromised function of the heart, and kidneys, which sometimes require transplantation. Wide-spread clotting problems can cause significant illness and even limb amputation. There also are frequent neurological and neuropsychiatric symptoms as highlighted in Part 3 of this series. Surprising manifestations continue to emerge, such as new-onset diabetes.

Lung scarring often occurs in patients who experienced COVID-caused acute respiratory distress syndrome (ARDS), a common problem seen in acute COVID patients who required ICU care. ARDS is a serious respiratory problem that can be caused by different respiratory viruses and other things. About a third of patients with ARDS arising from any cause were unemployed 5-years later because of their lung damage. It is fully expected that patients with COVID-related ARDS will be found to fare similarly.

There also is the dysfunctional immune response common in many moderate to severe COVID cases that can cause long-term multi-organ damage, particularly in the liver and kidneys. It can also disrupt coagulation control of the blood, sometimes leading to amputations, mostly in patients in their 30s and 40s. It was reported that amputations due to vascular problems have doubled since the CoV-2 virus arrived. Compromised coagulation control in COVID patients can also precipitate adverse cardiovascular events such as heart failure, or hemiplegia due to strokes. Data from the COVID Infection Survey on long-COVID suggest that the risk of major adverse cardiovascular events and long-term illness is about ten times higher in COVID patients (even after mild COVID) compared to non-COVID matched controls. A Dutch study found that 31% of COVID ICU patients suffered thrombotic complications. These problems can unexpectedly pop up in people who had completely recovered from COVID.

A global survey tallied 205 different symptoms across 10 different organ systems that can persist after COVID infection has cleared. Typically, these manifold long COVID symptoms do not appear in isolation, but in multi-symptom clusters. A long hauler typically has several of these problems at a time.

While it is estimated that overall, 10-30% of COVID patients become long haulers, reports on the number of people suffering long COVID vary widely. Depending on the report, anywhere from 30-90% of COVID survivors suffer long term health problems. And even at the lower end of that range, 30% of over 330 million people world-wide who have been infected is a very large number. It represents an enormous personal toll in terms of lost health and diminished quality of life. Some of these reports are summarized below.

• Half of 70,000 hospitalized UK COVID-19 patients experienced long-term complications, according to a study published in July. Complications occurred regardless of age group: For instance, 25% of adults aged 19-29 developed complications, as did 33% of those aged 30-39. Complications affecting the kidneys and respiratory system, liver injury, anemia, and arrhythmia were the most common.
• Many COVID-19 survivors require extensive and prolonged rehabilitation. An European study found about one-third of 1,837 non-hospitalized COVID patients (i.e., those with mild disease) needed a caregiver three months after their symptoms started.
• In April the CDC reported in its Morbidity and Mortality Weekly Report that 69 percent of nonhospitalized adult COVID patients in Georgia required
• one or more outpatient visits 28 to 180 days after their diagnosis.
• A study published last February in the Journal of the American Medical Association found that roughly one-third of 177 people who had mild COVID disease not requiring hospitalization reported persistent symptoms and a decline in quality of life up to nine months after illness.
• 70% of people hospitalized for COVID-19 in the UK had not fully recovered five months after hospital discharge. They averaged nine long COVID symptoms requiring continued medical care.
• A study in South Korea found that 90% of patients who recovered from acute COVID experienced long-term side effects.
• According to a report in the journal, Lancet, 75% of people hospitalized with COVID-19 in Wuhan early in the pandemic, reported continued problems with fatigue, weakness, sleep problems, anxiety and depression six months after being diagnosed with the disease. More than half also had persistent lung abnormalities.

Data like these have been commonly reported around the world, pointing to a more chronic and expensive health problem than seen with the flu or common cold, which often is caused by different coronaviruses. A July 2021 article in Scientific American talked about how all of this indicates that long COVID will cause a “tsunami of disability” that will affect individual lives as well as create enormous strain on the health system. Consider the numbers: More than 60 million Americans (this is an underestimate since many COVID cases are not reported) have been infected with the CoV-2 virus. Therefore, if only 30% of these suffer long COVID, we are talking about 20 million long haulers and counting.

The related health care and disability costs of all of this are also still being calculated. How many “long haulers” will not be able to return to work for months, or at all? How many will need short-term disability payments, and how many will become permanently dependent on disability programs? As increasing numbers of younger people become infected, will we see a generation of chronically ill? This then moves us to consider the economic and financial cost of long COVID, which will be the topic of the next installation in this series.

Stay tuned.

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Has Omicron Rendered Vaccines Ineffective?

Early in the pandemic, when we realized that the CoV-2 virus was quickly producing mutated progeny, some of which were becoming more deadly and transmissible, some (including your humble blogger) warned that viral mutation could feasibly give rise to a variant that ignored immunity to previous iterations of the germ—in other words able to ignore the current vaccines. We have arrived—almost.

The so-called omicron variant partly avoids immunity conferred by the current vaccines (and by prior infection), meaning that we are seeing “break-through” infections in fully and partially  immune people. Popular news sources are running headlines declaring that vaccinated patients with COVID are filling hospital beds, leading many to leap to the conclusion that the vaccines have failed.

But, that is not fully accurate. Many vaccinated people are indeed getting infected with omicron, yet the vaccines are still quite effective, and much better than no vaccine. Let me explain.

First, about two-thirds of Americans are vaccinated—a definite majority of the population. This means that for a hypothetical virus that can fully evade immunity, there are more vaccinated than unvaxed viral “targets” available; meaning more vaccinated than unvaccinated people will be infected. The reality, however, is that the vaccines are still partly protective so that many vaccinated people still catch omicron COVID. Yet, compared to vaxed people, unvaccinated people remain at significantly greater risk of infection, hospitalization, and death. Numbers in my State of Wisconsin, bear this out.

Currently, 69% of the State adult population is vaccinated. According to the latest data* (as of January 15, 2022), out of 100,000 vaccinated people, 1573 caught COVID, 18.5 were hospitalized, and just under 4 died. In contrast, out of 100,000 unvaccinated people, 4,746 got infected, 176 were hospitalized, and 51 died. In other words, many more unvaccinated adults are feeling the effects of COVID, despite representing only 30% of the State population. Clearly, there were breakthrough infections in vaccinated people, but just as clearly, unvaccinated people fared way worse than they would have if they had the shot.

Yet, the headlines persist, proclaiming things like, “Similar numbers of vaccinated and vaccinated people hospitalized for COVID.”   Does this not show that the vaccines are no longer effective? Not at all. Because many more people are vaccinated and partly susceptible to the virus, more and more vaccinated people are showing up with infection, but at a much lower rate than unvaccinated people do. The graphic below illustrates how this works.

The benefits of the vaccines also are reflected in national and world-wide numbers. The US has one of the lowest vaccination rates among developed countries such as the UK, Canada, Norway, Denmark, etc. And despite omicron’s “milder” nature, which means it kills fewer people but still kills, the COVID death rate in the less vaccinated US is greater than seen in more vaccinated countries, attesting to the efficacy of the shots. Also, new hospital admissions in the US have now reached an all-time high and far exceeding hospitalization rates in better vaccinated countries. Current data from New York State shows that hospitalization among the unvaccinated is 14x higher than among fully vaccinated people.

All of this demonstrates how effective the vaccines remain at preventing infection, hospitalization, and death from omicron-driven COVID. Places with higher vaccination rates, such as the UK and Canada, are not experiencing an increase in base case rates of patients admitted to the ICU or deaths, even with omicron cases skyrocketing. The US is.

Get your Fauci boo boo.

*Note on Wisconsin State data sources: State data mentioned here are from the Wisconsin Department of Health Services, Public Health Madison and Dane County, and the Wisconsin Hospital Association as reported Jan 15, 2022 in the Wisconsin State Journal.

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.

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Naturally Immune? You Still Better Get A Vaccine

Over 43 million Americans have reported cases of COVID-19. Many of them likely have some level of immunity that can be quite protective, even without vaccination. Even before vaccines were available, individuals who recovered from COVID-19 had detectable T-cell responses, and reinfections were rare, at least prior to the emergence of the more contagious Delta variant. This is what people refer to colloquially as “natural immunity,” to distinguish it from immunity conferred by vaccination. Some people claim that natural immunity is better and preferable to vaccine immunity and that a history of infection should count as much as being vaccinated when considering vaccine mandates. Is all this true? Well, like what we have seen and heard during the pandemic, a lot of truths have been spread, same with lies and disinformation. The story around natural immunity follows this pattern. Let me try to sort all this out here with a focus on whether previously infected people should consider getting vaccinated.

Natural infection can confer immunity to COVID. Like most viruses, previous infection with SARS-CoV-2 does confer immune protection against future re-exposure to the virus. Several peer-reviewed studies conducted in the early months of the pandemic, before vaccines were available, found that people previously infected were around 80% less likely to test positive for the virus during the next viral surge. These included studies of healthcare workers in the UK, the Danish population, and patients at the Cleveland Clinic, a large health system in Ohio and Florida.

Other data from the UK Office for National Statistics showed that between May and August 2021, a prior infection offered around the same level of protection against the Delta variant as vaccination. (Note that very recent and preliminary observations in South Africa suggest that infection with the new Omicron variant is high in people previously infected with other CoV-2 variants. However, since Omicron is so new and data on it are very sketchy at this time, this review will not further comment on this variant.)

A recent large Israeli study found that people who had been fully vaccinated with two Pfizer shots were 13 times more likely to later get infected with CoV-2 than those who had a prior infection. It also suggested that immunity from infection was longer lasting than that from vaccination. The study also showed that natural immunity plus the vaccine offered protection that was even stronger than either natural or vaccine immunity alone. This is one of the very few studies suggesting that natural immunity is better than vaccine immunity and has not been peer-reviewed. Furthermore, the subsequent rise of Delta since the end of this study confounds the issue a bit since Delta has been shown to be more infectious than the viruses the study subjects were exposed to. 

In the most recent review of the current scientific evidence by the CDC, they concluded that both fully vaccinated and those previously infected with the virus have a low risk of re-infection for at least six months, but that the two forms of immunity appear to have different strengths. Vaccination with mRNA vaccines produced higher concentrations of neutralizing antibodies—the type that prevent the virus from entering cells—than natural infection, although, over time, the antibody levels waned in both groups. However, long lasting immune memory conferred by natural infection appeared to be stronger than that conferred by vaccination.

Over time, immune B cells typically evolve to produce antibodies that better recognize an antigen, and an earlier study published in Nature found that antibodies produced by naturally immune memory B cells continued to evolve at least a year after infection. In contrast, antibodies produced by memory B cells in vaccinated people did not change much over time. This would suggest that over time, antibodies produced by natural immunity gain greater ability to respond to re-infection with the virus than antibodies produced by vaccination. One possible reason for this difference in the evolution of the anti-viral antibodies was that pieces of virus remain in the body for weeks after infection and continue to engage the immune cells, whereas vaccine lipid nanoparticles quickly fade away providing less immune stimulation. 

On the other hand, vaccine immunity might be better. So, as we have seen, a few reports suggest that natural immunity is superior to vaccine immunity. However, more studies suggest the opposite and even show that not everyone who catches COVID-19 will have effective immunity to re-infection. A CDC study reported that 36% of previously infected people did not form any antibodies against the virus. This is in stark contrast to antibody formation reported in 100% of people who received just one dose of an mRNA vaccine. Furthermore, the CDC reported in August that COVID survivors who went unvaxed were more than twice as likely as vaccinated people to get infected again contrasting with the Israeli study I mentioned earlier. Yet another CDC study looking at data from ~190 hospitals in nine states confirmed that unvaccinated people who survived an infection several months earlier were more than five times more likely to get COVID again than vaccinated people.

The reason that natural immunity might not always be effective is because the natural exposure to the virus is highly variable. People naturally infected are exposed to widely different doses of virus via different routes and possibly to different viral strains, all of which conspire to confer different degrees of protection. In contrast, vaccinated people receive standardized doses of the same viral antigen via the same route of exposure, making them more likely to develop a uniform degree of immunity. Researchers found that some people who had been infected had high antibody levels to the virus, while others had low levels, reflecting this variability in natural infection. This was substantiated by a new study from the University of Pittsburgh that also found that in many cases antibody levels from a prior infection are not high enough to protect people from getting sick again. Then, an Oxford study found that both long term T and B cell immune responses were highly variable in naturally immune people. The investigators took monthly samples of blood from infected subjects and measured their T and B cell responses over time. Interestingly, the variability in their responses was clearly identified as early as one-month post infection. Those with the weakest immunity at one month (25% of the subjects) had no detectable antibodies after six months. This contrasts to vaccine immunity, which does fade a bit over six months, but still remains consistently strong months after full vaccination. 

Finally, new evidence from an NIH-supported study from the Fred Hutchinson Cancer Research Center, Seattle showed that antibodies from vaccinated people better recognized the mutated spike proteins from viral variants than antibodies from naturally immune people who had not been vaccinated. In other words, vaccinated people seem better able to respond to mutated spike proteins present in new viral variants.

The bottom line. In sum, while natural immunity can be effective, most evidence shows that vaccines typically give rise to consistently better antibody and long term T and B cell responses.

Having made this point, it is important to further note that a combination of both types of immunity, or so-called hybrid immunity, appears to be stronger than either alone. Researchers found that vaccination of naturally infected people boosted antibody and memory B cells to levels higher than seen in those with just either type of immunity. People with prior COVID-19 who received even one vaccine dose had half the risk of a breakthrough infection than unvaccinated people with prior COVID-19. Another study from researchers at the Icahn School of Medicine in New York found that a single dose of either the Pfizer or Moderna vaccines produced more antibodies in people who had previously had COVID-19 than two vax doses did in those who had never encountered the virus. It also found that people with prior infection report more unpleasant, but not serious side effects from vaccination. Vaccinating previously infected people also elicits important cross-variant neutralizing antibodies that better protect them against the known viral variants. Hybrid immunity also appears to work in the other direction: A study of vaccinated people who were then infected during a July 4 holiday weekend outbreak on Cape Cod found that they produced higher levels of antibodies and T-cells directed against the virus. In sum, vaccination helps those with natural immunity (and everyone they interact with) and vice versa. 

For these reasons, the CDC now recommends that people who have had COVID-19 be vaccinated because the shots plus natural immunity have been shown to offer better protection than natural immunity alone.

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.

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Lessons for COVID Vaccinations And Herd Immunity From Influenza And Rubella

Note: The following is modified from the blog post, “Rubella: We vaccinate for far less,” by Katelyn Jetelina, MPS, PhD who is an “epidemiologist, biostatistian, professor, researcher, wife, and mom of two little girls.” She writes a blog entitled, “Your Local Epidemiologist.”

 “Those who cannot learn from history are doomed to repeat it.”

 George Santayana

 

In the US, more than 300,000 kids aged 5-11 have been vaccinated with the Pfizer COVID-19 vaccine, which has proven that the vaccine is safe and can benefit some kids. It prevents infection, COVID-19 disease, death, long COVID-19, and keeps kids in school. Admittedly, only a few kids develop serious COVID disease and fewer have died from it. Most infected kids only have mild, if any, symptoms. Vaccine skeptics use this fact to stridently argue against childhood COVID vaccines. So, why are we pushing to vaccinate children who rarely get seriously ill?

There are two reasons why we vaccinate anyone. The first reason is to protect the vax recipient from the disease; this is an individual-level benefit of the vaccine. The second is to protect a larger population by trying to retard disease spread; this is a population-level benefit of vaccines that is better known as herd immunity.

But, anti-vaxers only focus on the fact that childhood vaccines provide little individual-level benefit to children and wholly ignore the larger population-level benefit of the vaccines. As I have written before, vaccinating children who are at low risk for serious disease is still very important for reducing viral spread in order to  prevent more dangerous viral mutants from emerging. It also is important for reducing infection and disease in more vulnerable people in the population. It is these population-level benefits that are the most important reason to vaccinate low-risk children. Vaccinating children for a population-level benefit, rather than for individual-level benefit, is not at all new and is a very acceptable practice. Here are a couple of examples.

Influenza: A few decades ago, Japan mandated flu vaccines for all school kids. That vaccine slowed the spread of flu in schools leading to many fewer student illnesses and absences. More significantly, vaccinating all school kids also caused a sharp drop in flu deaths in older people like school teachers and staff, parents, and grandparents who have close contact with the kids.

Kids are walking incubators for respiratory viruses and readily spread their germs to others. Infected children essentially are virus vectors much like mosquitoes are vectors for malaria and yellow fever. Therefore, in Japan, the flu vaccine effectively shut down a major vector of influenza infection for at-risk older people. That is an undeniable and important population-level benefit of vaccinating school kids against the flu.

Rubella: Now, let us take a deeper dive into rubella, or German measles, and its vaccine, which is the “R” in the MMR shot. It is especially enlightening to compare the natural history of rubella to what we are learning about COVID-19.

Both COVID and rubella are caused by airborne viruses that spread when infected people cough, sneeze, or even talk. As with COVID, rubella symptoms in children are quite mild. They include its tell-tale measles-like rash, sore throat, low grade fever, mild pink eye, and general discomfort. But, about 25 to 50% of infected children will not experience any symptoms. Likewise, many CoV-2 infected kids also do not develop symptoms. But, asymptomatic kids infected with either rubella or CoV-2 readily spread their viruses to friends and family; hence, they can be significant vectors delivering both viruses to people at-risk for serious disease.

Over the last two years, we have learned that COVID mostly (with significant exceptions) causes serious illness and death in older people or for those with certain other health conditions. Similarly, while rubella only causes mild disease in most children, it is incredibly dangerous for developing fetuses. A woman infected with rubella during the first 3 months of pregnancy has a 90% chance that the fetus either will not survive or will develop Congenital Rubella Syndrome (CRS), characterized by deafness, blindness, heart defects, and/or severe brain damage. In the early 1960s, a rubella outbreak began in Europe and spread to the US. In 1964-65 ~12.5 million total cases were reported in America affecting nearly 50,000 pregnancies. More than 11,000 of the infected mothers miscarried, or delivered still-born babies. Of the >20,000 infants born alive to infected mothers, the majority had severe illnesses: 2,100 died shortly after birth, 12,000 were deaf, 3,580 were blind, and 1,800 had permanent mental disabilities.

The rubella outbreak proved hard to contain because, as with COVID, infected asymptomatic people make it hard to know when someone is spreading the virus. Rubella also is just as contagious as COVID. Both viruses have an R₀ = 6-7 meaning that each infected person will infect, on average, 6-7 other people. For comparison, flu’s R₀ = 2-3, which means it is about half as contagious as the other two viruses. It, therefore, is not surprising that like rubella, the COVID outbreak is proving hard to contain.

Soon after the 1960s rubella pandemic began, a safe and effective vaccine was quickly developed and approved for use in Europe and North America (this is reminiscent of the quick development of the COVID vaccines). Early on, there was a robust international debate on who should get the rubella vaccine. There were two schools of thought:

1. Despite the fact that rubella only caused mild problems in kids, some proposed vaccinating all children hoping to provide indirect population-level protection for pregnant women and their at-risk fetuses.
2. Others argued that because children were only minimally affected they should not be subjected to the vaccine and that only women of childbearing age should be vaccinated. This, proponents argued, would more specifically protect those most at risk.

Ultimately, it was found that countries that chose #2 were not able to sufficiently reduce the virus, because it still spread unfettered among children. This strategy did not reduce the rates of CRS. Eventually, option #1, vaccinating low-risk children (like what we are moving toward with the COVID vaccine) was adopted world-wide. Vaccination rates of school kids reached ~85% in the US, which last experienced a serious rubella outbreak in 1995. In 2004, transmission of rubella was eliminated in the United States and in 2015, it was eliminated in all the countries of North and South America.

Soon, the MMR vaccination was mandated for children in all 50 states. It is important to realize that these mandates were not to protect kids from the mild disease but to protect the at-risk population, or fetuses. In other words, we vaccinate kids against rubella not so much to protect them, but to provide a significant population-level benefit to others.

Today, because of broad rubella vaccination of low-risk children, we see an annual average of just 10-15 cases of CRS in the US that are traced back to international travel to countries with poor rubella vaccination rates. In contrast, in countries with low vaccination rates, about 120,000 children are born each year with severe CRS birth defects and even more die in utero.

Bottom Line: This country, and indeed all of the Americas and most of Europe came together to eliminate endemic rubella through broad population-level vaccination programs targeting low-risk groups responsible for spreading the virus to the high risk population. Japan saw the same effect with influenza. They focused on broadly vaccinating a low-risk population (school kids) and saw great benefits in the high-risk older population. As we approach a broad COVID vaccination strategy that includes giving the shot to low-risk children, it very likely will have a population-level benefit and help protect those most at-risk for serious disease.

It is important to note that the population-benefit conferred by the COVID vaccine also applies to all of us and not just to children. When we are vaccinated, not only does it protect us, it also provides significant protection to at-risk people around us. That, in fact, is called “herd immunity.”

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