The Next Pandemic Is Here

Who ya gonna call?  --“Ghostbusters”

We seem to have mostly weathered two-plus years of a pandemic like the world has not seen in our lifetimes. It raced across the globe killing and maiming people, and overwhelming health care capabilities. Sure, we have read the history about the black plague, small pox, and the Spanish flu pandemics, but vicarious experience through books and film is no substitute for first-hand experience. We now have that experience. It was sobering to see the novel SARS-CoV-2 virus ravage country after country while medical experts played a desperate game of catch-up to learn how to retard the spread of a brand new virus and how to treat the brand new COVID-19 disease it spawned. It was sobering seeing and hearing about people we know get very ill and sometimes die, and sobering reading the statistics of millions of deaths that occurred worldwide.

While most of us today have not seen such a pandemic wild-fire before, we have seen other, more smoldering pandemics that do not spread as fast. HIV is a good example. It too is a world-wide disease that, for many years was a death sentence for those who were infected. Now it is a well-managed chronic disease, thanks to medical science.

The world was not as frantic over HIV and AIDS as we were over CoV-2 and COVID. The reasons for this are probably two-fold: First, it was quickly recognized that AIDS was largely limited to homosexual men and IV drug users and, therefore, was not an eminent threat to most of us. It was not necessary to quarantine, mask up, and shut down businesses and schools in order to prevent catching the “gay disease.” Second, despite the world-wide spread of AIDS, it is not easy to catch. You must be in very intimate contact with an infected person to catch it—it is not caught by simply breathing the same air as an infected person like COVID is. Clearly, not all pandemics are created equal. Some smolder like AIDS, others fulminate like COVID. What will our next pandemic be like?

As the global population grows, as the climate changes, as humans push into spaces occupied by wild animals, and as we continue enjoying our ever increasing global connectedness, future pandemics become more likely. We are not guaranteed the luxury of facing just one a century, or even one at a time. As greatly encouraging, even exciting as it was to watch the post-molecular BioX science, as I have called it, roar into life to produce several effective and novel anti-CoV-2 vaccines in record time, there is no guarantee BioX can save us next time.

Well, the “next pandemic” already is upon us and BioX is struggling to deal with it. This pandemic is not as volatile as COVID or the Spanish flu. In fact, compared to COVID, it is a “slow mo’” pandemic, more like AIDS. But, it promises to be more difficult than COVID, even for BioX, to mitigate. It currently kills about 700,000 people annually around the world, but threatens to kill 10 million people a year by 2050 (in contrast, COVID killed ~6 million around the world in 2.5 years).

The problem

 In March 1942, Anne Miller of New Haven, Connecticut, was near death. A bacterial infection had made its way into her bloodstream, which was a death sentence at that time. Desperate to save her, doctors administered an experimental drug called penicillin, which Alexander Fleming accidentally discovered 14 years earlier. In just hours, she recovered, becoming the first person to ever be saved by an antibiotic. Rather than dying in her thirties, Mrs. Miller lived to be 90 years old and Fleming went on to win the Nobel Prize for his inadvertent discovery.

Today, decades later, germs like the one that infected Mrs. Miller, but easily eradicated with antibiotics, are increasingly becoming resistant to penicillin and the many other antibiotics that have since been developed. There is a very good chance that right now, you have such a “superbug” in or on your body—a resistant germ that, given the opportunity could enthusiastically sicken you leaving medical people at a loss on how to treat you. You would be at the mercy of the bug just as all patients with a microbial infection were before Mrs. Miller.

We are not talking about a new, exotic germ like CoV-2 suddenly appearing and ravishing the world. The antimicrobial resistance crisis stems from the simple fact that new antibiotic development cannot keep pace with the rate that common microbes become resistant to antibiotics. This very slowly growing pandemic we are now in involves run-of-the-mill pathogens, bacteria and fungi that have caused disease since humans first dragged their knuckles on the earth. These are bugs which we had well controlled with antibacterial and antifungal drugs, but there is a very definite trend toward these germs becoming resistant to ALL known antimicrobial medicines we have. Infection with multidrug resistant pathogens is the slow moving pandemic that already is among us but that is growing at a logarithmic rate.

Since multi-drug-resistant infections do not respond to our antibiotics, treatment increasingly involves surgically removing an infected organ. For example, in the case of drug-resistant Clostridioides difficile (aka, “C-diff) colitis, an emergency colectomy is performed when patients no longer respond to antibiotic therapy. CDC data show C-diff infections occur in half a million patients each year, and at least 29,000 die within one month of initial diagnosis. Up to 30% of patients with severe C-diff colitis develop sepsis require emergency surgery, and still their mortality remains high.

As of 2019, about 18 drug resistant pathogens affected >3 million people in the US, causing 48,000 deaths. These bugs cause pneumonia, septic shock, various GI problems, STDs, urinary tract infections, typhoid fever, TB, and infection with the so-called “flesh eating bacteria.” Compared to COVID, this has received relatively little attention in the popular press, but has been a frequent topic in medical lectures and conferences for the last 20 or more years. These infectious disease lectures tend to scare the bejeebers out my colleagues and me. This smoldering pandemic is that serious.

And it is not just antibiotic-resistant bacteria we have to worry about. Certain fungi, especially of the Candida genus, cause various serious ailments in people. Recently, for the first time, the CDC reported five unrelated cases (two in DC and three in Texas) of people infected with fungi that showed “de novo” resistance to all drugs. Usually, drug resistant fungi only appear after infected patients have been treated with antifungals. But, the patients in these five de novo cases had no prior exposure to antifungal drugs. The fungi were already drug-resistant when they infected the patients; they were picked up from the environment already resistant to our medicines.

Antibiotic resistance is now one of the biggest threats to global health. It occurs naturally in naturally occurring pathogens, but is accelerated by overuse of antibiotics in humans and animals, especially farm animals. What happens is that upon treatment with an antibiotic, a single infectious bug out of a population of millions or billions fortuitously mutates and becomes resistant to the antibiotic. The antibiotic then kills off all the non-resistant population, including beneficial bacteria, opening the door for the drug-resistant pathogen to take over. This resistance can occur via many different mechanisms. The bacteria or fungal cell can stop taking up the drug, it can spit out the drug if it is taken up, it can neutralize the drug once it takes it up, or it can change its internal machinery so that it no longer responds to the drug. This problem can be further exacerbated since bacteria and fungi can pass along their mutations by sharing mobile genetic material with their progeny and even with other bugs in their immediate environment that have never been exposed to the antibiotic. They can even pass along this DNA to microbes of different species. Bacteria can also pick up DNA remnants left over from dead germs. Thus, DNA that confers resistance to anti-microbial drugs can spread to the environment even in treated human and animal waste contaminating lakes and streams and ground water.

Currently, the major problem with drug resistant infections occurs in in-patient clinical settings—perhaps you have seen the heightened infection control efforts (gowns, gloves, masks, and isolation) in hospitals designed to prevent the spread of untreatable pathogens. People receiving health care, especially those with weakened immune systems, are at higher risk for getting an infection. Routine procedures, such as bladder catheterization or kidney dialysis are common ways to introduce drug resistant germs into clinical patients. But, infection can happen in any surgical or invasive procedure. Treatment of diabetes, cancer, and organ transplantation can weaken a person’s immune system making them even more susceptible for infections that either are, or that can become drug resistant.

But, antibiotic infections can also occur in the community outside of clinical settings. There is the case of Mike who needed a month long hospital stay for kidney failure after bringing home a new puppy from which he caught a multidrug-resistant Campylobacter infection. He was one of 113 people across 17 states who was part of an outbreak linked to pet store puppies. He recovered after surgery to remove a dead section of his stomach.

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The NIH Hospital Experience. About 10 years ago, the NIH Clinical Center in Bethesda was hit with an epidemic of drug resistant infections that killed a number of patients in just a few months. It was such an intractable problem that NIH finally had to gas rooms with a disinfectant, rip out plumbing, and build a wall to isolate infected patients. Still, over a period of six months it reached 17 patients, 11 of whom died. In this case, the bug was Klebsiella pneumoniae, which arrived in June 2011 with a 43-year-old female lung transplant patient who had just transferred from New York City. NIH nurses noted something startling in her chart: She was carrying an antibiotic-resistant infection.

Desperately trying to contain the superbug before it could spread, the NIH staff quickly isolated the woman in the ICU. Staff members donned disposable gowns and gloves before entering her room and her nurses cared for no other patients. After a month, the patient was discharged and the staff believed that their containment measures had worked. There were no signs that the bacteria had spread. But a few weeks later, they were shocked when a second patient tested positive for resistant Klebsiella. A third and fourth soon followed and all these patients died.

This pattern was baffling since, if the bug had not been cleared, it should have reappeared sooner. Even though it was the same type of bacteria, K. pneumoniae, perhaps it had spontaneously arisen anew in the other three patients. But by reading the genomes of the bacteria isolated from each patient, including the NYC transfer, scientists at NIH’s National Human Genome Research Institute saw that the bacteria in the subsequent patients came from the New York patient.

That meant two unsettling things: The bacteria lingered for weeks unnoticed in the hospital environment; and the hospital’s infection control measures for the New York patient failed. A further search for the bacteria found it on a ventilator that had been bleached twice. They also found it in a sink drain in a patient’s room, so they tore out all the plumbing. Yet, it began popping up it in more patients, at a rate of about one per week.

As hospital staff desperately raced to stanch the outbreak, they also struggled to treat the infected patients. Out of desperation, doctors battling the deadly, drug-resistant superbug turned to colistin, an antibiotic of last resort. It is not a new drug, having been discovered in 1949 in a beaker of fermenting bacteria in Japan. It had quickly fallen out of favor then since it causes significant kidney damage. The fact that the doctors resorted to such an old, dangerous drug highlights the lack of new antibiotics coming out of the pharmaceutical pipeline even in the face of a global epidemic of hospital-acquired bugs that quickly grow resistant to our toughest drugs.

While colistin defeated the superbug in a few patients, in at least four, the bacteria evolved so rapidly it outran colistin, too. Those four died. This was when the wall was built and all new Klebsiella-positive patients were moved into a new isolation unit behind the wall. Blood pressure cuffs and other normally reusable gear were tossed after one use. Clinical monitors were hired to follow doctors and nurses around to ensure that they were donning gowns, gloves and masks, and scrubbing their hands after seeing each patient.

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Among the most concerning mutating bacteria are carbapenem-resistant Enterobacteriaceae (CRE). Enterobacteriaceae are a large family of more than 70 bacteria that includes the common E. coli, that normally live in the digestive system and help digest food. But, if conditions allow the bacteria to leave the digestive system, they can cause serious disease that needs to be treated with antibiotics. They too can quickly develop resistance to front-line drugs and become a serious problem.  Carbapenem is an antibiotic "drug of last resort" used to treat disease caused by bacteria resistant to other front line antibiotics. Therefore, CRE are resistant to all or nearly all antibiotics and kill up to half the >13,000 patients who get bloodstream infections from them. The CDC first detected this type of antibiotic-resistant bacteria in 2000. Since then, it has been reported in 41 states. In the 10 years between 2001 and 2011, the percentage of Enterobacteriaceae resistant to antibiotics increased almost fourfold according to the CDC. Recently, the CDC tracked one type of CRE from a single health-care facility to facilities in at least 42 states.

The cause

The antimicrobial resistance crisis stems from the simple fact that new antibiotic development cannot keep pace with the rate that bacteria become resistant to antibiotics. Between 1945 and 1968, drug companies invented 13 new categories of antibiotics. Between 1968 and today, just two new categories of antibiotics have arrived. In 1980, the FDA approved 4-5 new antibiotics a year, but now only about 1-2 new drugs are submitted annually for approval. Hence, the solution appears quite simple: Develop more novel antibiotics. However, this is quite complicated since BioX science, which led to the rapid development of the novel mRNA anti-COVID vaccines, has not quite caught up to novel antibiotic development. There are two general reasons for this. First, finding a drug that disrupts the metabolism of bacteria or fungi, but that does not interfere with mammalian biochemical pathways is a difficult and narrow path. Second, so far, the market for novel antibiotics has been comparatively small, meaning that the profit incentive for pharma companies has not been large compared to that for so-called lifestyle medications. While a new antibiotic may bring in a billion dollars over its lifetime, a drug for heart disease may net $10 billion. Drugs to treat depression and erectile dysfunction are typically taken for years making them much more profitable than antibiotics that are used short-term.

Development of bact resistance

Even if we could develop new antibiotics faster, their overuse is the primary driver of antibiotic resistance. According to the CDC, in 2018 seven antibiotic prescriptions were written for every 10 Americans. Of these, one-third were unnecessary, and very often were prescribed for viral illnesses that do not respond to antibiotics. Clinicians writing these prescriptions argue that the antibiotic can help prevent the primary viral infection from leading to a secondary bacterial infection. In other words, many antibiotics are prescribed for prophylaxis rather than treatment.

Time to resistance

The number of new antibiotics that the FDA approves annually has slowed to a trickle, while the rate of bacterial mutation has grown exponentially. It used to take 21 years on average for bacteria to become resistant when antibiotics were first used. Now it takes just 1 year for bacteria to develop drug resistance because antibiotics are so readily prescribed and used. Today, the CDC lists 18 different types of antibiotic-resistant bacteria, five of which are classified as urgent threats to human health.

Physician-prescribed antibiotics, however, are not the only, or even main, source of our antibiotic resistance crisis. In the U.S., 70%-80% of all antibiotics are given to animals, especially farm animals destined for human consumption.  Drug-resistant pathogens from farm animals can spread to the environment providing a gateway through which drug resistant germs can quickly spread across our communities, food supply, and even our soil and water around the world.

Surprisingly, antibiotic use is even rampant in salmon and other fish farms, which is especially concerning, considering that 90% of fresh salmon eaten in the U.S. comes from such farms. Antibiotic-resistant infections also affect petting zoo animals, which can then transfer the germs to people.

The solution

Antibiotics clearly have been miracle medicines, saving countless lives; however, anytime they are used, they drive the development of antibiotic resistant pathogens that ultimately defeat their purpose.  Developing new antimicrobial drugs to counter the growing resistance to current drugs is not working; it is not keeping pace with the appearance of new antibiotic resistant germs. Without drastic changes in the science and economics behind antibiotic development and business, this will only be a partial solution to the growing pandemic. However, what we can do now is resort to low-tech, less expensive, and more innovative mitigation measures. These include alternative prevention steps such as more judicious use of antibiotics and increased use of isolation and sanitation measures (where have we heard this before?). Isolation and sanitation defenses against infectious diseases have been part of our disease fighting repertoire since the earliest awareness that contagions can spread through communities. It is an ancient remedy, but still the most effective way to protect ourselves against contagious diseases worldwide. Between 2013-2019, these mitigation measures led to an 18% reduction in US deaths from drug resistant infections. It always is better to prevent than treat.

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Alternative medical treatment and prevention options.  Besides the obvious masks, gloves, sanitation, and quarantine measures, there are other alternative medical (i.e., non-antibiotic) options that can be used to prevent and control drug resistant infection. In fact, these methods are often preferable to using antibiotics, which also deplete the microbiome of “good bacteria” that are critical for good health. These options include vaccines, therapeutic antibodies, and bacteriophages.

From 2000 to 2016, members of the WHO increased the use of the pneumococcal vaccine around the world, thereby decreasing antibiotic use which slowed the development of antibiotic resistant S. pneumoniae saving ~250,000 children from death. Pneumonia caused by secondary infection with other bacteria is a leading cause of complications and death in patients who get the flu. Therefore, the influenza vaccines also are effective tools to decrease the risk of drug-resistant bacterial pneumonias by preventing viral influenza. Since patients with COVID can also develop secondary complications from bacterial pneumonia, COVID vaccination now is another important weapon in the arsenal to prevent the development of antibiotic resistant bacterial lung infection.  

In recent years, healthcare providers also have been increasingly using therapeutic antibodies to treat viral and bacterial infection. For example, antibody therapy is often used to treat recurrent C-diff GI infections, and antibodies to prevent and treat bacterial associated pneumonia also are being developed. So far, we have not seen bacteria develop resistance to antibodies.

Finally, a different and very novel approach to dealing with untreatable bacterial infection has recently taken advantage of bacteriophages, which are viruses that can specifically infect and kill bacteria. There are a few cases in which phage therapy has been used to cure people dying of multidrug-resistant bacterial infections.  According to Pew Charitable Trusts, as of June 2019, 29 non-antibiotic products like therapeutic antibodies and phages were in clinical development and seven were in Phase 3 clinical trials. 

Perhaps BioX is indeed coming to rescue us from the growing pandemic of drug-resistant pathogens.

Notes: 1) By way of disclaimer, your correspondent has consulted for a biotech company that engages in “big genome” research to search for novel antibiotic molecules produced by everyday bacteria and fungi that grow in the soil under your feet. Something like this could be part of the future of novel antibiotic development. 2) In order to have blog updates delivered to your email, see the simple Subscription Instructions here. Remember, you can easily unsubscribe when you want. But, you can’t beat the price.


COVID More Deadly Than Flu For Kids

In the US, nearly six times more kids and teens died from COVID in one year than did from the flu, according to a new analysis of pediatric mortality data. According to CDC data, childhood flu deaths have ranged from 39 to 199 per year since 2004. Meanwhile, in 2021 alone, more than 600 children died from Covid-19, according to an analysis done by researchers at the Harvard University Medical School and at Brigham and Women’s Hospital in Boston.  The analysis used data from the CDC to compare COVID deaths during the pandemic to flu deaths over the last decade (see figure below).

Of the known respiratory viruses, only CoV-2 has ever killed more than 100 US kids in a single month since the middle of the 20th century. Much of that is because we have long had vaccines for other viruses that cause human respiratory disease, but have yet to widely vaccinate children against COVID-19. Hopefully, new vaccines will also render COVID less deadly for kids like vaccines have done for several other respiratory diseases.

Throughout the pandemic, some have argued that COVID poses little health risk to kids aside from a few days of sniffles. Though kids often experience less-severe symptoms than adults, COVID is still a very real risk. An estimated half a million kids now deal with long COVID, a number that experts say is likely an undercount because its myriad symptoms make it tricky to diagnose.

Mortality in kids


Masks Redux

"You’ve got to be very careful if you don’t know where you are going, because you might not get there."

—Yogi Berra

As cases of COVID-19 ascend in areas of the US, some schools are reverting to requiring masks. Of course this is accompanied by renewed claims that they are ineffective. In fact, Florida governor Ron DeSantis issued an executive order barring local school districts from requiring their students to wear masks, claiming that there was no evidence that masks prevent infection in schools. That claim has been levied over and over by many politicians, talking heads, pundits, and assorted Facebook “experts.” But, they are flat wrong. There are multiple lines of evidence from a variety of disciplines—including materials science, infectious diseases, pediatrics and epidemiology—showing that masks can help protect children and teachers from getting COVID in schools. Some of that evidence has already been presented in these pages, and I now add to that body of evidence, more  data recently summarized in Scientific American.

  1. For starters, laboratory experiments show that masks block the respiratory droplets and aerosols that transmit SARS-CoV-2, the virus that causes COVID. In one test, an engineering team at the University of Wisconsin–Madison used a machine in a classroom setting to pump out particles the same size as those that carry the virus from an infected person. The researchers placed several CPR dummies with or without masks around the room and measured the degree to which the aerosols penetrated the masks. They reported that a surgical mask reduced the chances of penetration by 382 times when compared to the maskless mannequins.
  2. Then, in the real world, not a laboratory setting, several epidemiological studies also concluded that masks in schools work. Researchers at the ABC Science Collaborative in North Carolina collected data from more than a million K–12 students and staff members from schools across that state, which mandated masking in schools from August 2020 until July 2021. The scientists reported little in-school transmission when the mask mandates were in place during the fall, winter or summer months. During this time, in-school transmission remained low as COVID cases fluctuated outside the schools. With mask mandates, rates of within-school spread were as low as one percent.
  3. Masks, combined with other prevention efforts, also reduce the risk that students might bring home the virus to parents or other relatives. An online survey of 2.1 million Americans by researchers at Johns Hopkins University showed a 38 percent increased risk of COVID-related illness in households with a child attending school in person. That risk went down, however, as the number of school-based mitigation measures, including mask mandates went up.
  4. Studies done in wider communities beyond schools give the strongest real-world evidence that masks stop COVID’s spread. An international team of researchers conducted a randomized controlled trial involving nearly 350,000 people across 600 villages in rural Bangladesh. Half of the villages got free cloth or surgical masks and a promotional campaign encouraging their use. The other half did not. The researchers found that the mask intervention significantly curbed coronavirus transmission.

Bottom line:  The effectiveness of masks in schools is supported by many different studies and analyses that show similar results. There are more than a dozen studies beyond those cited here, that all point to the same conclusion:

Masks work.

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What Happened To The Flu And Other Respiratory Diseases?

A NYC based travel blogger who travels a lot used to get a respiratory infection whenever she flew. That stopped when the airline mask mandates went into effect. The mandates, of course, were designed to hinder the spread of the CoV-2 virus that causes COVID, but it makes sense that if masks and other physical (that is, non-medical) mandates worked to mitigate COVID, then we would see a decrease in other contagious respiratory diseases after the mandates were, well…mandated.

We did.

The mandates worked, despite persistent claims of some to the contrary. This particular blog subject was stimulated by a radio talk show where a couple of nonscientist talking heads announced that there was no scientific proof that the masks or other mandates prevented disease. I previously posted in these pages evidence that masks, in particular, do indeed work to retard the spread of disease (see here, here, here, and here). In this post, I present further data on how the mandates significantly reduced the incidence of other infectious respiratory diseases around the world. If the measures can reduce flu, then you can bet that they also reduced COVID-19.

Note, however, that this is not necessarily an endorsement for returning to the measures. Your humble scribe didn’t much like his glasses fogging up, or having to make two trips from the car to the store because he forgot his mask. But, let’s argue the issue based on its merits and not from false premises based on incorrect claims.

After South Korea implemented various hygiene and social distancing measures in response to COVID, they saw the 2019-20 flu season end an astounding 12 weeks earlier than the previous year. Epidemiological surveillance data bolstered by clinical diagnostic testing showed that infection from several different pathogenic respiratory viruses (including adenovirus, bocavirus, metapneumovirus, rhinovirus, flu, parainfluenza, and respiratory syncytial virus) dropped to nearly 0% just five weeks into 2020!

In the United States, the incidence of infection by influenza, respiratory adenovirus, rhinovirus, enterovirus, RSV, non-COVID coronaviruses, metapneumovirus, and parainfluenza viruses all decreased in March 2020, soon after implementation of mandates. Similar results were seen in Japan.

More dramatically, since pandemic mitigation measures were put in place, there has been a 99% global reduction of infections from both influenza types A and B compared to prior years. In particular, one of two flu B substrains has not been isolated in the world since August 2021 suggesting that this variant is now extinct. The overall genetic diversity of influenza viruses has also dramatically diminished indicating that other flu sub-types (or clades) have disappeared around the world since the pandemic mandates were put in place.

And this reduction of respiratory infectious disease does not only hold for those caused by viruses. Another study looked at surveillance data from 26 countries across 6 continents for several bacterial diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, which are typically transmitted via respiratory droplets. Numbers of weekly cases in 2020 were compared with corresponding data for 2018 and 2019. Data for disease due to Streptococcus agalactiae, a non-respiratory pathogen, were also collected from nine laboratories for comparison. All countries experienced a significant and sustained reduction in respiratory bacterial diseases in early 2020 (Jan 1 to May 31), coinciding with the introduction of non-medical COVID containment measures in each country. By contrast, the incidence of disease due to S agalactiae (which is not transmitted by the respiratory route) did not differ significantly from the 2 previous years.

Clearly, the mandates significantly reduced the incidence of respiratory infections by non-COVID viruses and bacteria. They worked. So, why did we still have COVID infections after the mandates went into place? The mandates reduced, not eliminated these diseases, so infections still happened. Since we did not have historical COVID infection data from previous years to compare with, the effects of the current mandates on the incidence of COVID are not as clear cut as they are with other diseases for which we do have historical data for comparison. But, as I wrote before (see above), it is clear that places in the US and around the world that used masks and other protective measures saw reduced incidence of COVID compared to similar places that did not.

Bottom line: The studies mentioned here regarding non-COVID infectious diseases fully support data previously posted in these pages that the mandates, including masks, are effective non-medical tools for controlling infectious respiratory diseases.

Don’t let anyone tell you differently.


A Single Gene Doubles Risk Of COVID Death

“Nothing shocks me. I’m a scientist.” —Indiana Jones

British scientists recently identified an allele, or a version of a gene, that portends lung failure and death in COVID-19 patients. Research recently published in the journal Nature Genetics, found that a poorly studied gene expressed in lungs, designated LZTFL1, has a variant form that does not differ in its coding sequence. That is, the different alleles of the gene express the same protein sequence. They do differ, however, in their non-coding sequences that regulate expression of the gene. When expressed, the gene product prevents cells lining airways and the lungs from responding properly to the CoV-2 virus. The lining of the lung essentially transforms into less specialized cells which affects their normal function.

Previous work had identified a stretch of DNA on human chromosome 3 that doubled the risk of death from COVID. Using an artificial intelligence algorithm to analyze millions of genetic sequences from hundreds of cell types from all parts of the body, the Oxford University Howard Hughes research team honed in on the lung-specific genetic off-on switch. This is another example of what I previously labeled "BioX," the new frontier of bioscience, or post-molecular biology science.

Importantly, the variant allele that augurs a worse lung response to infection does not affect the immune system. Therefore, the it is probable that vaccination remains the best way to protect these at-risk patients. Finding this new allele could also lead to novel therapies to target the pathway affected by this genetic variant to provide targeted treatment for at-risk populations.

The troublesome variant is mostly found in people of South Asian ancestry—some 60% of whom carry the allele—which partly explains the severe devastation from COVID seen in the Indian subcontinent. In contrast, 15% of those with European ancestry and 2% of Afro-Caribbean people carry the risky allele.

It will be interesting to see if this lung-specific gene also affects the course of other respiratory infectious diseases.

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Lingering Post-COVID Vascular Risks

George Burns once opined that “the secret of a good sermon is to have a good beginning and a good ending; and to have the two as close together as possible.” The same might be said for blogs. If so, this is a pretty good blog post.

We have known for some time that patients with COVID-19 are at risk for dangerous blood clots (also called deep vein thrombosis, or DVT), pulmonary embolism, and bleeding. Findings reported this month in the British Medical Journal reveal that this risk continues several months after COVID recovery.

The study compared more than one million people in Sweden who had COVID-19 to a control group of more than 4 million people who did not. The overall risks for each problem were low, but still elevated for up to six months following COVID. According to the report, DVT occurred in 0.04% of patients who had had COVID and in just 0.01% of control patients during the same time. Pulmonary embolism occurred in 0.17% of post-COVID patients and in 0.004% of control patients. And bleeding events occurred in 0.10% of patients who had recovered from COVID, while only 0.04% of control patients had such a problem.

While the risks of blood clots and bleeding were highest in patients whose COVID had been more severe, those who had had mild COVID still showed an elevated risk.

Bottom line: You are not out of the woods after you recover from COVID. Significant problems can arise a few months later.

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COVID-Diabetes Link Confirmed

As I penned in these virtual pages almost a year ago, COVID survivors have a high risk for developing diabetes. Early on, diabetes was identified as a risk factor for severe COVID illness, but two years later, scientists were surprised by the unforseen reverse correlation between COVID and the metabolic condition. The increased risk for diabetes in COVID survivors was recently confirmed by US and German scientists.

A study of more than 180,000 American veterans done at the St. Louis VA Health Care System found that COVID survivors were 40% more likely to get a new diagnosis of diabetes within a year of their COVID diagnosis than a control group of veterans who avoided the virus. That works out to about 13.5 extra cases of diabetes per 1,000 COVID patients.

The increased risk for diabetes was evident even in people who had a low risk of diabetes before COVID, and the likelihood of newly diagnosed diabetes increased with the level of care patients received for COVID. In other words, the sicker the patients were with COVID, the more likely they were to develop diabetes.

The other study from Germany found that people who had mild COVID cases were 28% more likely to be diagnosed with type 2 diabetes compared to a control group consisting of patients who had an upper respiratory tract infection caused by a different bug. That study was based on an analysis of electronic records from a nationwide primary care database that followed patients, including almost 36,000 COVID cases, for 3-5 months. This means that these newly diagnosed cases of diabetes arose quickly after COVID infection, and were not a result of general respiratory infection, but were a specific consequence of CoV-2 infection.

Questions remain about whether diabetes that follows COVID is just temporary and reversible after patients fully recover, or whether it leads to chronic disease. In other words, if you had even mild COVID, you should ask your doctor to screen you for diabetes, which simply entails a fasting blood draw to test for glucose and hemoglobin A1c levels, which are elevated in diabetic patients.

A lingering question is how COVID leads to diabetes. Does the virus directly affect the insulin-secreting beta cells in the islets of the pancreas, or is new-onset diabetes caused by metabolic changes in fat cells which we know are readily infected by the virus. It is also possible that insulin production is perturbed by viral damage to the cells that line vessels supplying blood to the pancreas, indirectly causing death of insulin producing cells. A more trivial cause for post-COVID diabetes could simply be an unveiling of incipient diabetes that might have gone undiagnosed because people have been away from the health-care system during the pandemic. It is also possible that steroid medications prescribed to tame the COVID inflammatory response could elevate glucose levels in the blood, leading to a diabetes diagnosis.

Research into the cause of the COVID-diabetes link continues apace—stay tuned.

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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.

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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 2nd 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, 16th 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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