The (Vaccine) Booster Wars: A prepost


We’re always reading about how the pandemic has created a new emphasis on preprints, so it stands to reason that non-reviewed preposts would now have a place in blogs. Maybe then I’ll “publish” some of the half-baked posts languishing on draft in I’ll update or replace this prepost after reviewing.

The Booster wars

Like most wars, the recent “booster wars” have (unintended) casualties. I refer, of course, to the disagreement about whether third shots of Covid vaccines are called for because of the evidence of waning protection after 6 or so months, coupled with the more virulent delta variant. Last week’s skirmish, resulting in the FDA advisory committee voting 16 to 2 against approving a third shot of Pfizer’s vaccine (to anyone over 16) seemed to be more of a backlash by some members in FDA’s Office of Vaccines against being sidelined by the White House when they announced last month already that a booster shot was forthcoming for all. (Two members, including the director of the Office of Vaccines is leaving, presumably as a result, at least that’s how it was described in the press). The FDA advisory committee claimed there was not enough evidence of benefit to recommend boosters for all, given the unknown risks such as myocarditis (although the data Pfizer presented include just 1 case, I believe).

I watched the last 3 hours of the day’s session on Friday September 17. (It was oddly reassuring that the FDA had at least as many technical glitches with zoom as the rest of us; but not reassuring to see the seeming cavalier attitude of some members). Right after voting the booster plan down the panel immediately turned around and approved the booster for anyone over 65 or who was in a severe risk group. Then, 15 minutes later, they broadened that to include anyone “at high risk of occupational exposure”—at any level of exposure—to Covid,  such as healthcare workers, teachers and many others.

Do our health experts realize how detrimental their infighting is to the rest of us? Couldn’t they have come to somewhat of an agreement—at least as to how to explain their opposed standpoints—before making rival pronouncements and issuing dueling preprints? For at least one whole month now, we’ve been witnessing squabbling agencies. It came as a surprise to hear Biden/Fauci announce in mid-August that boosters were necessary, it was only a matter of time. “Even among government scientists, the idea has been met with skepticism and anger” we read in the NYT. Fauci said last month it would probably be 8 months, no make that 6 months (after the last vaccine).[1] “Fauci said: he was ‘certain that Americans would need booster shots of the COVID-19 vaccine” possibly at 5 months! Today he even strengthened that view, asserting “the third shots should be viewed as a part of the COVID-19 vaccine regimen, just like the first and second shots,… I think that three shots will be the actual correct regimen”. 

Does that mean he’s prepared now, despite the analysis of the FDA panel, to have the booster mandated wherever the others currently are? Apparently.

We’d all love to see the plan

So what would the plan be then? Boosters every 6 months? Israel is preparing for a 4th dose already. What about the development of boosters for Delta and other variants? Is that in the works in the U.S.? And if boosters are to be recommended on the basis of declining levels of neutralizing antibodies (correlated, it is thought, with breakthrough cases), why not recommend people test their levels? I did go out and get my levels tested a couple of weeks ago but it was anything but routine. Friday’s FDA panel voted to wait until more evidence is in. If our numbers are high, then, is it advisable to wait, even if we fall into the FDA’s (vague) permissible category? The answers we are getting are simplistic, defensive, and, to my knowledge, don’t address this and other fairly obvious conundrums for an anxious public.

The main basis for the rejection by the FDA panel was described in a Lancet article appearing right before: they find the available evidence pointing to the need for boosters to be weak, based on observational studies, they claim, of just a few weeks:

“Randomised trials are relatively easy to interpret reliably, but there are substantial challenges in estimating vaccine efficacy from observational studies undertaken in the context of rapid vaccine roll-out.

Although the benefits of primary COVID-19 vaccination clearly outweigh the risks, there could be risks if boosters are widely introduced too soon, or too frequently, especially with vaccines that can have immune-mediated side-effects (such as myocarditis, which is more common after the second dose of some mRNA vaccines, or Guillain-Barre syndrome, which has been associated with adenovirus-vectored COVID-19 vaccines). If unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond COVID-19 vaccines. Thus, widespread boosting should be undertaken only if there is clear evidence that it is appropriate.”[2]

This seems a sensible precautionary stance, unfortunately obscured by the feeling it reflected agency power dynamics.[3] Maybe the U.S. would have more of its own data, if the CDC had not stopped recording breakthrough infections in May, 2021 (except for those who are hospitalized or die). Anyway, Fauci does not address the panel’s concerns about limited data. But, given those concerns, it does make one wonder why the same panel turned around and recommended approval of the booster for various occupations, rather than recommending waiting for more data. The FDA’s misgivings will doubtless also give grounds for unvaccinees to point out that even the FDA is worried about safety of the approved vaccines. After all, a third dose, 6 months after the second, does not seem substantially riskier, especially given the lack of caveats when telling those who have had Covid to get fully vaccinated in addition. Actually, it now appears that getting vaxxed after having Covid provides “superhuman” Covid immunity.

Will our immunity (from vaccinations) evolve, or be obstructed?

In a study published online last month, [Paul] Bieniasz and his colleagues found antibodies in these individuals that can strongly neutralize the six variants of concern tested, including delta and beta, as well as several other viruses related to SARS-CoV-2, including one in bats, two in pangolins and the one that caused the first coronavirus pandemic, SARS-CoV-1. (see link)

In fact, these antibodies were even able to deactivate a virus engineered, on purpose, to be highly resistant to neutralization. This virus contained 20 mutations that are known to prevent SARS-CoV-2 antibodies from binding to it. Antibodies from people who were only vaccinated or who only had prior coronavirus infections were essentially useless against this mutant virus. But antibodies in people with the “hybrid immunity” could neutralize it.

Understandably, many are excited about the possibility that a booster shot will create, in vaccinated people, the kind of “super-human” immunity response seen in those who followed Covid infections with vaccines (i.e., those with hybrid immunity). Then Covid, it is thought, would become like the common cold. Even though it was only 14 people, that they all showed this is impressive. (There isn’t information on the reverse order, vaccine, then infection.) Throughout the pandemic, I have found that Paul Bieniasz, who led this study, is doing some of the most interesting and path-breaking work.

But there are worries by other researchers that repeated infection with one strain can actually reduce the development of immunity to novel strains—although you don’t typically hear about this.

In the case of Covid, some scientists are concerned that the immune system’s reaction to the vaccines being deployed now could leave an indelible imprint, and that next-generation products, updated in response to emerging variants of the SARS-CoV-2, won’t confer as much protection. (Stat News)

Immunologists call this ‘original antigenic sin, and it is apparently a key obstacle to creating immunity to flu variants—although, again, we don’t hear about it in the yearly prodding to get flu shots.

The concern is that even when a booster variant comes along, our immune systems, having repeatedly encountered the early Covid variant, will largely trigger neutralizing antibodies to it rather than the novel variant. As such, I’ve heard some doctors advise people to try to go as long as they can with the primary shots. To know how long to wait, we’d need to know our (approximate) neutralizing antibody levels. As of now, if you do manage to get a quantitative test (no dichotomania), you have to go through non-standard channels to find an interpretation of numbers. Not even doctors seem to know. The public is capable of understanding that, at present, there is no clear “correlate of protection” as they call it, (between neutralizing antibodies and infection); that’s not a reason to obscure or bury the information, especially as policy decisions that affect them rely on precisely these numbers. We should also be conducting studies to test what those numbers mean in terms of infection, disease and transmission (V. Prasad)

Here are some very useful discussions:

It may be argued that future booster variants are going to be so loaded up that they will force our immune systems to pay attention (to the new variant)–but are we sure? And do we want to get to that point? Of course, like many of you,  I’m just a member of the non-expert lay population whose life is affected by Covid policy decisions that are made without my input. (I don’t know what P. Bieniasz thinks of this, but he’s convincing on the need for boosters.)

A simple first step

We’re bound to hear, any day now—perhaps even before I put up this prepost—of the FDA’s ruling on Pfizer, based on Friday’s FDA panel. Presumably they will concur with the panel, and a similar approval seems likely for Moderna in a few weeks (although I hear Moderna wants the booster to be a half dose of the original[4]). But these narrow rulings will not address the broad and legitimate questions people have, and without answers to those questions, people cannot wisely decide whether to take up any opportunity to get a booster. This just increases the feeling that agencies and politicians have their agendas, and we have to fend for ourselves. As a simple first step, how about calling all of the point people on Covid vaccines together—being particularly sure to include representatives of rival positions—to address these specific questions, and reveal the uncertainties that are the engine behind their policies, although they are generally hidden under wraps. Not one of these hour long glitzy “roundtables”, but an extended (and perhaps ongoing) forum, where answers are challenged by others and by data.

Lest people start to have hesitations with this new policy, why not give the public the information they need to critically navigate the pandemic for themselves? It’s fairly clear that our agencies aren’t doing it for us.

What do you think? Please write with your thoughts and corrections. I’d be interested to hear as well, what questions you’d like the vaccine and virology experts to answer. 


[1] In Mid-august, CDC director Walensky, agreeing with Fauci, gave these reasons for boosting: “First, vaccine-induced protection against SARS-CoV-2 infection begins to decrease over time. Second, vaccine effectiveness against severe disease, hospitalization and death remains relatively high. And third, vaccine effectiveness is generally decreased against the delta variant.” (Washington Post)

[2] An additional shot has already been approved for anyone considered immunocompromised. Several other countries are either contemplating or already giving boosters.

[3] Perhaps the disagreement is between the weight to be given infections vs severe disease. Or perhaps it’s about which is worse: that announcing boosters would increase vaccine hesitancy, or that declining anti-virus potency of vaccines will increase transmission. They also felt it would be more beneficial to increase global vaccination, but the committee announced at the start, that such considerations would not be considered relevant.

[4] So are half-doses being manufactured, or will people who want Moderna boosters have to wait until they’re produced?

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19 thoughts on “The (Vaccine) Booster Wars: A prepost

  1. rkenett

    The Israeli data supporting the booster (Pfizer) was published in 10.1056/NEJMoa2114255

    The meeting where it was discussed (in Hebrew) before bein presented to the FDA panel was recorded in

    The round table discussion on this at the Samuel Neaman Institute was summarized (in Hebrew) in

  2. How does one apply the concepts of error statistics to the research leading to policy recommendations on booster doses? How rigorous should the research be before acting on it?

    • Bill: No one, not even the experts FDA vaccine panelists and expert virologists can decide how rigorous research should be for you before acting on it–it’s a value question. What they ought to give us, is sufficient information to make the value judgment, and they don’t even come close to covering obvious information. So, I’m afraid many of us are likely to act incorrectly. With respect to their own charge–which is to take an action based on evidence–they certainly don’t seem to rely on anything remotely systematic. Error statistics says we need to know how poorly probed the various claims they’re making are. What concerning risks haven’t been probed at all. They owe us a frank acknowledgment about where they might be wrong, and what mistakes and risks one would want to know about in order to wisely balance our own benefits and risks. Instead we get utter chaos and disagreement between agencies. They won’t tell us anything they surmise would result in our acting in a manner other than what they’ve decided we should do. Instead of information we get behavioral manipulations. I’ll come back to your query, but I want to see what the FDA and CDC have actually said today–I hadn’t had time earlier. I will report back to the blog.

  3. So, the FDA did decide to follow the panel’s recommendations yesterday, with the details to emerge today. I saw the following in an article about Moderna boosters:

    The composition of the booster shot remains the same as the original for this year because Moderna had not had enough time to change it.
    “We are currently testing Delta-optimized variants in clinical trials. They will form the basis for the booster vaccination for 2022. We are also trying out Delta plus Beta, the next mutation that scientists believe is likely.”

    Given my levels are high, I’m thinking of waiting for the Delta or Delta plus Beta booster, but might change my mind once Moderna gets approval for its current booster.

  4. CDC policy options

    All but #4 were given yes votes. They expressed concern not to go beyond what the FDA approved, but they actually exclude the high risk occupations such as healthcare workers (unlike they have “underlying disease”) by saying no to #4.

  5. The results of today’s and yesterday’s votes at CDC & FDA convey the message that the current vaccines are inadequate–even though all panel members agreed there wasn’t data for this.
    I hope my PFE stock goes up at least.

  6. CDC overruled the last allowing it for high risk occupations. People will undoubtedly run out and get boosted (since it’s written as “recommended”, whereas they really only mean “permitted”, contingent on an individual risk/benefit assessment), never mind that so many questions have still not even been raised, e.g., are those boosted with 3 ineligible for a variant booster when it comes?

  7. Steven McKinney

    We should all pay less attention (not necessarily no attention) to what a committee of scientists do and say in the meetings that they hold, and pay much more attention to the publications that ensue from those meetings. People need some space to deliberate complex, and especially new problems. Initial deliberations for any new issue will at first appear chaotic and scattered, as people organize their thoughts and ideas on the new problem. We should not watch those deliberations and panic. We should take a breath, calm down and also do some thinking of our own.

    Of course the deliberations about coronavirus issues will yield some initial “infighting”, this is a new virus with many unknown properties. How the human body will react to a new virus is always unknown, so people will have widely ranging ideas. This is why people need closed-door meetings and some initial degree of privacy, executive privilege and the like, so they can hash out complex ideas without being pilloried at the early stages of a new and confounding dilemma.

    I still maintain my confidence that a reasonably selected group of scientists will eventually steer us all straight. Their initial findings must always be taken with a grain of salt.

    So I am not going to take as final, any pronouncement about booster shots for the coronavirus at this point.

    I know that booster shots are a thing, I get annual influenza vaccines because I work in an institution with immunocompromised patients in the vicinity. I recently had two Shingrix vaccine boosters, after watching my mother suffer a recurrence of her nascent chickenpox virus, which lay dormant in her nerve cells for decades, which nearly robbed her of her left eye.

    So too will I get a coronavirus booster, when the time and circumstances are right. I will not rush out now, in a panic, fibbing to pharmacists to get an extra jab. I will wait patiently, social distancing and wearing a mask, until a booster shot is made available to me, based on reasonably vetted evidence. I am most fortunate to live in British Columbia, where our current provincial government and our public health official Dr. Bonnie Henry have shown one very competent strategy in handling a pandemic. If you live somewhere with incompetent leadership and are wondering what to do, keep an eye on what the British Columbia Provincial Health Office is doing.

    With a population of 5 million, British Columbia has had 1866 coronavirus deaths. With a population of 330 million, the USA could be sitting at 125,000 deaths had the strategies employed in B.C. been adopted in the USA. Half a million people did not need to die in the past year.

    There’s a fantastic series from Canada’s public broadcaster CBC titled “How to think about science”, a series of 24 interviews with a wide range of scientists including Simon Schaffer, Lorraine Daston, Lee Smolin, Wendell Berry, Ruth Hubbard and more. This series explores the human side of the scientific endeavour. No matter the high ideals of the effort we label “science”, it is an activity conducted by humans, and humans are a complicated and messy bunch. Though the scientific effort is to uncover truths about nature, people are complex, they argue, they battle for seats of power in institutions and engage in other activities that make the production of science a messy affair.

    None of us can know everything, so in the arena of science, we have to develop “trust networks”, the people and groups that we have consistently seen to get answers right, or at least close to right. As a personal example, John Ioannidis used to be in my trust network, with his ideas about properly assessing published research findings. He is certainly not in my trust network as concerns covid, his now long list of ridiculous ideas and shoddy analyses on preprint servers displaying his apparent need to be in the limelight rather than conduct sound science.

    Current problems in science are no surprise to followers of Error Statistics and Deborah Mayo, where the “Statistics Wars” are an important area of deliberation. Similar infighting has been seen aplenty in the now decades long debates about climate change. Oil company propagandists have successfully exposed the squabbling of climate scientists through hacked email chains in an effort to sully the image of sincere groups of scientists dealing with another unique situation for which no data is available, namely what happens when CO2 levels in the atmosphere nearly double within a few decades, a mere blink of the geologic eye.

    No less messy are the efforts of scientists, both sincere and duplicitous, in understanding and dealing with a new pandemic.

    It is sad for me to have watched this pandemic unfold, and be so miserably handled by the last US Federal government under the “leadership” of a wanna-be-dictator. The full display of human messiness in a scientific arena was there for all of us to see. Some scientists in China, seeking to educate, rapidly publishing the coronavirus genetic sequence, while others were arrested and sequestered for political reasons. Some scientists in the USA, Europe and elsewhere beginning the development of vaccines within days of the publishing of the coronavirus genetic sequence, using vaccine technologies already in place with many years of study behind them, from the SARS and Ebola and Zika virus experiences. Other “scientists” seeking the limelight, and positions of power, sidling up to boneheaded presidents and spouting ridiculous approaches to handling a pandemic, dressed in fancy scarves and hawking unproven snake oil. “Scientists” pushing hundreds of papers onto bioarXiv and other preprint repositories that would never be published by any well run journal, yet garnering far too much attention on the social media platforms that plague us with misguided silliness.

    Mayo: “Do our health experts realize how detrimental their infighting is to the rest of us?”

    I’m sure that many of them do, which is why they generally have closed-door meetings to hash these things out. Unfortunately, due to the necessity of social distancing, they have chosen to conduct these meetings with technological meeting solutions such as Zoom, and not kept the meetings private. We should give them time and space to deliberate and not judge them too quickly, unless we see that they are really off the rails, looking to garlic poultices and horse de-wormers and other snake oil strategies that obviously are not appropriate.

    Mayo: “Couldn’t they have come to somewhat of an agreement – at least as to how to explain their opposed standpoints – before making rival pronouncements and issuing duelling preprints?”

    We should, indeed, give them space to do so. I don’t grab on to any initial position espoused for precisely this reason. When pronouncements are made, there’s still the need for additional scientists to weigh in on the rival pronouncements. That is the incremental, iterative process that is science. I remember Dr. Fauci recommending against masks in the earliest phases of this pandemic, though now there is plenty of evidence of the effectiveness of even simple cloth masks at slowing the transmission rate of an airborne virus, which he now readily espouses. I’ll be listening to Dr. Fauci’s ideas on the boosters, because he has a decades-long history of eventually getting to the right answers on these complex issues, and remains in my trust network. The fact that we were able to get an emergency use authorization for a vaccine so quickly is thanks in large part to Dr. Fauci’s efforts to help speed things up in the regulatory realm after the AIDS epidemic left people dying without treatments for far too long.

    Mayo: “For at least one whole month now, we’ve been witnessing squabbling agencies.”

    That is the scientific enterprise at play, a messy affair conducted by people. Give them some time to hash things out. Who among us can come to the correct conclusion about a new, complicated matter, in an instant? Unfortunately, the urgency of the life and death issue that a pandemic presents impels people to develop initial strategies quickly, and of course rapidly made decisions aren’t always the best. I will not judge them too harshly for their initial pronouncements. We will need a year at least to gather the amount of reasonable evidence upon which to base sound stances on the efficacy of coronavirus boosters. I will not be surprised if the final answer is that the most efficacious boosters are based on coronavirus variants, much as we get annual flu boosters based on flu variants, but we will need time and data to make such assessments. Current pronouncements will not necessarily stand the test of time.

    The CBC series is available at

    I highly recommend it if you want to explore the social complexities of humans in a large project seeking the truth.

    • Steven:
      Thank you so much for your enlightening and sagacious comment! I will study it and follow up on links. What you say below seems altogether plausible:

      “I will not be surprised if the final answer is that the most efficacious boosters are based on coronavirus variants, much as we get annual flu boosters based on flu variants, but we will need time and data to make such assessments.”

      What bothers me is that none of our Covid health leaders is talking about this–to my knowledge. I also worry that the drug companies have less incentive to develop these variant boosters if the agencies are all hunky dory with more of the old ones. If the health agencies said,
      “by the way, if you’ve had a booster, we do not recommend another booster within the year, even if it’s a Covid variant, therefore take seriously your current risk/benefits before running headlong into getting a booster”, people would think twice.

      With the current panic, I think there’s a feeling of wanting to do something, so if we’re offered boosters we feel we should get them and not resist them. Since Moderna hasn’t come out with a booster yet, doubtless people will either go for Pfizer or get the full dose of Moderna–even though neither of these might be the best for them.

  8. Steven McKinney

    Variant vaccine development is being discussed at high levels, though not receiving much press.

    The FDA addressed the issue of policies and requirements for developers of vaccines using covid-19 variants in February 2021.

    Coronavirus (COVID-19) Update: FDA Issues Policies to Guide Medical Product Developers Addressing Virus Variants
    Suite of Guidances Addresses Vaccines, Diagnostics and Therapeutics

    For Immediate Release:
    February 22, 2021

    Health Canada also addressed the issue in March 2021.

    March 4, 2021 | Ottawa, Ontario | Health Canada

    “Health Canada announces new guidance issued today by the Access Consortium—a coalition of regulatory authorities from Canada, the U.K., Australia, Singapore and Switzerland. The guidance, developed by Health Canada in consultation with its Access partners, lays out what information regulators would need to approve any modifications to authorized COVID-19 vaccines, should virus mutations make them less effective at preventing COVID-19. With this guidance, authorized COVID-19 vaccines that are modified in response to new variants will need to be reviewed and authorized.

    According to the guidance, vaccine manufacturers would need to provide evidence that the modified vaccine produces an immune response in a sufficient number of people, but clinical studies would not be needed since they do not add to the regulatory understanding of a vaccine’s safety, efficacy or quality. 

    This is because researchers are now better able to measure protection by looking at antibodies in the blood following vaccination, reducing the need to determine whether people in a trial develop the disease. This would reduce the length of time needed for a modified vaccine to be ready for use.

    Along with data on the immune response, the vaccine manufacturer would also be expected to provide evidence of the modified vaccine’s safety and quality. Data from the original clinical trials and the ongoing studies on real-world use in millions of people can be used to support any decision by the regulators.”

    There is some recognition that full-blown trials may not be necessary, as the underlying vaccine may well remain the same, the only difference being the mRNA inserted in the vaccine. Viral antibody titres demonstrating levels comparable with existing vaccines will need to be shown, and some form of safety data. Stephen Senn may well have some good insights here.

    I’m sure the drug companies are eager to get on with this, it’s just more guaranteed sales and of course the cost of developing a variant vaccine will be far lower than the initial cost of setting up the original. I remain cautious of drug company press releases, and am grateful that the CDC once again has a competent leader. The CDC and FDA have done reasonable work at vetting the information concerning the vaccines already distributed, which are working well with very very low side effect rates. There are now good checks and treatment options in place to catch and mitigate adverse events.

    So an ongoing iterative process of drug company development (with profit motivation needing regulatory oversight) and health agency review (with political interference needing public citizen oversight) will help us further navigate this pandemic.

    • Steven:
      Thanks so much for this! I had not heard that variant boosters might not require trials because of knowledge of antibody correlates. I wonder if this is also true in the U.S., which might explain the booster go ahead, despite the FDA finding the evidence weak. All the more reason that we should all be given access to test our neutralizing antibody levels!

  9. It’s interesting that Paul Offit, who was on the FDA review committee, and skeptical of the need for boosters, plans to hold off getting one for himself, although he qualifies.

  10. “Ali Ellebedy, an immunologist at Washington University in St. Louis, told me that the longer those cells mature in the body, the more prepared they are to fight off the invader. Delivered too early, another dose of the vaccine could end up “restarting something that was already working,” he said. Ellebedy recommended delaying any booster shots by at least six months from your initial course of vaccination. Eight months is better; even a year would be fine.”

  11. We do not hear too much about reinfection of Covid among people who have recovered from it. There is a study:
    SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN)

    Because the CDC stopped recording breakthroughs except for those hospitalized or among medical workers, our data is limited. As I’d mentioned in this post, getting a vax after recovering produces what
    Bienasz called “super immunity”, but “natural immunity” alone appears to last at least 8 months, a year or more, according to some of their results:

    “Natural immunity to SARS-CoV-2 appears to confer a protective effect for at least a year, which is similar to the protection reported in recent vaccine studies. However, the observation ended before SARS-CoV-2 variants began to spread…”

    In another article:

    “In a commentary in the same journal, Florian Krammer, PhD, of the Icahn School of Medicine at Mount Sinai in New York City, said that although natural infection tends to induce lower and more variable antibody concentrations than COVID-19 vaccines, ‘the findings of the authors suggest that infection and the development of an antibody response provides protection similar to or even better than currently used SARS-CoV-2 vaccines’.

    • Why is there so much difference between the U.S. and the rest of the world as regards the status of people who have recovered from Covid? I’m guessing it’s both simplicity of mandating vaccination for all and the politics. But is it ethical?
      “Other countries do give past infection some immunological currency. Israel recommends that people who have had covid-19 wait three months before getting one mRNA vaccine dose and offers a “green pass” (vaccine passport) to those with a positive serological result regardless of vaccination.19 In the European Union, people are eligible for an EU digital covid certificate after a single dose of an mRNA vaccine if they have had a positive test result within the past six months, allowing travel between 27 EU member states.20 In the UK, people with a positive polymerase chain reaction (PCR) test result can obtain the NHS covid pass up until 180 days after infection.21”

  12. The FDA met last night to discuss Moderna boosters. Unsurprisingly, they voted in favor of a parallel rule to the Pfizer booster. I tuned in because I was interested to see what data Moderna was going to present, and also because I thought the discussion last time was of interest. In the discussion at the end as to whether to extend the eligibility for the booster to all, I was a little surprised at how strongly those who spoke were opposed. Paul Offit, who is a member of the committee said he was holding off to see “how this thing plays out”, even though he is of age. Again, I think testing neutralizing antibody rates would help give people information as to whether the time is right for them.

  13. A very intriguing article on original antigenic sin. I wish the FDA advisory committees would discuss this. I wonder if the limitations it poses is the reason they haven’t come up with a booster variant yet.

  14. July 22, 2022: Things have changed a lot in less than a year. On one big concern–original antigenic sin–it may well be happening after all. I just read an article in the July 15, 2022 issue of Science discussed here
    that gives evidence of imprinting from the variants one was infected with. Unanswered is whether the vax has a similar affect.
    A clear, short summary

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