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The Latest on COVID-19 Boosters

Posted on by Dr. Francis Collins

COVID-19 Vaccine vials labeled dose one, dose two, and booster

More than 180 million Americans, including more than 80 percent of people over age 65, are fully vaccinated against the SARS-CoV-2 virus responsible for COVID-19. There’s no question that full vaccination is the best way to protect yourself against this devastating virus and reduce your chances of developing severe or long-lasting illness if you do get sick. But, to stay ahead of this terrible virus, important questions do remain. A big one right now is: How soon will booster shots be needed and for whom?

The answers to this question will continue to evolve as more high-quality data become available. But here’s what we know right now for the Pfizer-BioNTech booster. Late last week, Dr. Rochelle Walensky, the Director of the Centers for Disease Control and Prevention (CDC), recommended that:

  • Those 65 years and older and residents in long-term care settings should receive a booster shot at least 6 months after being fully vaccinated with the Pfizer-BioNTech vaccine,
  • People aged 50–64 years with underlying medical conditions should receive a booster shot at least 6 months after being fully vaccinated with the Pfizer-BioNTech vaccine,
  • Individuals aged 18–49 years with underlying medical conditions may receive a booster shot at least 6 months after getting fully vaccinated with their Pfizer-BioNTech vaccine, based on their individual benefits and risks.
  • Frontline workers who received the Pfizer-BioNTech vaccine may receive a booster. This group includes anyone age 18 through 64 whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of COVID-19. [1]

Taken together, these CDC recommendations are in line with those issued two days earlier by the Food and Drug Administration (FDA) [2].

Some of the most-compelling data that was under review came from an Israeli study, published recently in the New England Journal of Medicine, that explored the benefit of booster shots for older people [3]. Israel, with a population of around 9 million, has a national health system and one of the world’s highest COVID-19 vaccination rates. That country’s vaccination campaign, based solely on Pfizer-BioNTech, was organized early in 2021, and so its experience is about three months ahead of ours here in the U.S. These features, plus some of the world’s largest integrated health record databases, have made Israel an important source of early data on how the Pfizer-BioNTech mRNA vaccine can be expected to work in the real world over time.

Earlier this year, Israeli public health officials noted evidence for an increased number of breakthrough infections, some of which were severe. So, at the end of July 2021, Israel approved the administration of third doses, or “boosters,” of the Pfizer-BioNTech vaccine for people ages 60 and up who had received their second dose at least five months before.

To find out how well these booster shots worked to bolster immune protection against COVID-19, researchers looked to more than 1.1 million fully vaccinated people who were at least 60 years old. They compared the rate of confirmed COVID-19 infection and severe illness from the end of July to the end of August among people who’d received a booster at least 12 days earlier with those who hadn’t gotten boosters.

Nearly 13,500 older individuals who’d been fully vaccinated before March 2021, got a breakthrough infection during the two months of study. Importantly, the rate of confirmed infection in the group that got boosters was 10 times lower on average than in the group that didn’t get boosters. The data on severe illness looked even better. Of course, there could be other factors at play that weren’t accounted for in the study, but the findings certainly suggest that a third Pfizer shot is safe and effective for older people.

Though the Israeli studies on booster shots are a little ahead of the international pack, we are starting to see results from the research underway in the U.S. Last week, for example, Johnson & Johnson announced new data in support of boosters to improve and extend immune protection in those who received its single-dose COVID-19 vaccine [4]. For people who received the Moderna mRNA vaccine, the company has already submitted its data to the FDA for booster authorization. A decision is expected soon.

As the critical evidence on boosters continues to emerge, the most important way to avoid another winter surge of COVID-19 is to follow all public health recommendations. Most importantly, that includes getting fully vaccinated if you haven’t already, and encouraging others around you to do the same. If you’re currently eligible for a booster shot, they are available at 80,000 locations across the nation, and can help you stay healthy and well for the coming holiday season.

For others eager to do everything possible to protect themselves, their families, and their communities against this terrible virus—but who are not yet eligible for a booster—sit tight for now. The data on booster shots are still coming in for folks like me who were immunized with the Moderna or Johnson & Johnson vaccines. It’s likely that the FDA and CDC will widen their recommendations in the coming weeks.

In the meantime, the Delta variant is still out there and circulating. That makes it critical to maintain vigilance. Wear a mask in indoor spaces, keep a physical distance from others, and remember to wash your hands frequently. We are all really tired of COVID-19, but patience is still required as we learn more about how best to stay ahead of this virus.


[1] CDC statement on ACIP booster recommendations. Centers for Disease Control and Prevention news release. September 24, 2021

[2] FDA authorizes booster dose of Pfizer-BioNTech COVID-19 vaccine for certain populations. Food and Drug Administration news release. September 22, 2021

[3] Protection of BNT162b2 vaccine booster against Covid-19 in Israel. Bar-On YM, Goldberg Y, Mandel M, Bodenheimer O, Freedman L, Kalkstein N, Mizrahi B, Alroy-Preis S, Ash N, Milo R, Huppert A. N Engl J Med. 2021 Sep 15.

[4] Johnson & Johnson announces real-world evidence and Phase 3 data confirming strong and long-lasting protection of single-shot COVID-19 vaccine in the U.S. Johnson & Johnson. September 21, 2021.


COVID-19 Research (NIH)


  • James Simmons says:

    Yes, what about mRNA boosters? Thanks.

    • James Studlo says:

      Why is there no comment regarding the reinfection rate in COVID survivors with natural immunity relative to break though infection in vaccinated individuals in the same Israeli study.

    • Eva says:

      We’re from the Netherlands. Me, my family and friends all had Covid last year. Some of them even had it twice. And we all survived it like it was a influenza. No one is vaccinated. We al have a great immunsystem.
      So my question is? Why do we (who with great succes survived Covid ones and some of us even twice) get punnished for not being vaccinated?

    • Miles K. says:

      I had my last Moderna Vaccine 5 months and 2 weeks ago, after this week I will not have access to my 6 month Moderna Booster. What are the possible risks if the booster is administered at 28 weeks instead of the recommended full 30 weeks?

  • David Marvez says:

    For those in the AstraZeneca trial, what is the guidance? There may be some 20k individuals in this trial who revived two shots but have not received information on what they should do. AstraZeneca has remained silent on this point.

  • Martin L. says:

    I have tried to find information on why the Moderna booster approval has been delayed. The only thing I can find is that it is still being evaluated and approval may come in the coming weeks. Meanwhile, approval has been given to administer a Moderna booster to immunocompromised individuals. To me it makes no sense that this cohort can receive a Moderna booster while those of us who are over 65 with several major underlying conditions ,who are not immunocompromised, cannot get the booster. I am going to get my flu shot today and because I am over 65, I will receive the Fluzone high dose version. The high dose version is given because seniors have up to a 75% reduction in antibody response. I would say that by definition, all seniors are somewhat immunocompromised!

    • Sherry Fuzesy says:

      I am 73 and have been vaccinated with Moderna in March 2021. I am not immune compromised by strictly medical standards.
      It would be reassuring to know how many weeks, months before I qualify for the booster.

      • Mary S. says:

        I’m 72y. Moderna 2nd dose on 3/20/2021. Breakthrough infection symptom onset on 10/12/2021 (Day 1). Positive antigen test on Day 5. Fortunate with Mild symptoms thus far through Day 6. Isolating per CDC guidance. No info on timing to get my booster relative to breakthrough and I really want that booster!!

    • Steve White says:

      I think a lot of people have gotten the booster shot by claiming they are getting their first vaccination – if someone does that, the question becomes – should they get the same vaccine they already got? Israel is giving the same Pfizer vaccine as a booster but should people get one of the others, which, per some small studies, are going to give them more protection against Delta variant? I wish CDC would answer these questions in detail – I realize it’s their normal practice to approve one medicine at a time, for one purpose – but this does not address the question, which “booster” is best to get.

      Also, why do we not have a Delta specific booster? And, in my related Comment – why do they keep letting variants into the US?

  • Bonnie Mann says:

    What about the Moderna and Johnson and Johnson Booster?

    • George H says:

      What about them? If they can convince the government that they have a safe product as Pfizer has, then they might be able to get their product to market too. The Chief Minister of the A.C.T. here in Australia has ordered all Pfizer for the booster shots. Irrelevant if one has taken Astra, Moderna, Sinovax, Sputnik or Arsenic for the double-laced vaccines. ALL will receive an mRNA booster. One size fits all. As Henry Ford once said: “You can have any Model T you like. They all come in black”.

  • JJ Sikora says:

    Why isn’t Novamax being given FDA emergency approval. All the research indicates its efficacy is higher and its side effects are lower. So???

  • Steve White says:

    I have to ask some questions which I think CDC is obligated to answer

    1. Why do we keep getting variants? I realize some will arise within the US and so they are inevitable – but Alpha, Beta, Gamma Delta, are all from outside the US – did they really need to get here? Because they came in on people who could have been monitored better, didn’t they? A REAL quarantine as Australia and New Zealand have – which did not stop every case but combined with good tracking seems to have kept out those variants – could have been done in the US – why wasn’t it? I think it worth pointing out – if vaccine development and manufacture are continuing at a frantic pace as many hope, just keeping a variant out for a couple of months could be a huge advantage. Right now, we have an honor system where we assume a traveler’s negative Covid test is not a forgery, then assume he stays quarantined for two weeks after he arrives – has ANYONE, in all human history, traveled around the world to stay in a hotel room for 2 weeks? We do not even have apps to track them on their cell phones. Complete farce, and not to get political, but obviously the situation at the border means that is another huge hole in the system.

    2. Why are we not given the CDC’s best guess as to the most effective boosters to give now? Some study reported Moderna vaccine was more effective against Delta than Pfizer – if that is true, we want to give the Pfizer people Moderna (and maybe vice versa). Merely approving Pfizer would be sub-optimal, and CDC must address this ASAP. What is the optimal protocol with the tools we have now?

    3. What is being done to get new vaccines against the variants? This is a huge problem, potentially. I realize private industry is trying to stay ahead of the variants but we need to know what is being done, in general terms, and know it does not depend on decisions made in one company, or even two, that the best job of staying ahead of variants is being done. But we see no news on that ?????

    • Jojo says:

      1. Australia has a population of 25 million. NZ, ~5 million. Both of these countries respond to national orders.

      OTOH, the USA has 331 million. We have 50 separate governments that do not have to listen to a central government order (states rights and all that). So quarantining and monitoring people here is a much more challenging task.

      3. It takes time t decode the changes in a variant and then do all the work necessary to run through formal approvals before being able to distribute it. Luckily, the human immune system doesn’t have these problems. It decodes and deals with new invaders quickly and efficiently, something it has perfected over hundreds of thousands, if not millions of years. If you were to get infected w/o the vaccine, you would most likely survive and would gain full natural immunity, which is good against all variants. A little known fact is that only 1% of the people who get infected with Covid wind up in the hospital. But you wouldn’t know that if you listen to mainstream reporting, where they make it seem like anyone getting Covid better have a will in place.

      As to Covid variants, there is a one for you to worry about – R.1!

  • William Howard Mills says:

    What about Astra Zeneca

  • Pierre Cambron says:

    My comment is rather a question. Can we make a booster shot with another vaccine than the initial one?

  • Julia says:

    Why is the CDC age cut-off for seniors set at age 65 – when the Israel study indicated boosters were good for those over age 60? Is it because most of the other CDC databases relevant for defining seniors in the USA use age 65 as cutoff for seniors just because that happens to be the Medicare age? What was the safety and efficacy data and/or policy rationale that CDC used to indicate that Pfizer boosters were not needed yet for all those age 60-64 now?

  • Judy S. says:

    I have a friend who said her husband just received the Moderna booster shot. I have suggested that she may be mistaken as the Moderna booster is not approved yet for use. Twice she has responded that it was definitely a Moderna booster, and he got it because of his underling health conditions. It is not a clinical trial, I asked that also. So are there some isolated instances where the Moderna booster is already being given to certain people? Just curious. I am happy to wait until it receives the final approvals.

  • Nena says:

    Clinical trials leading to approval with small Ns, usually are not very meaningful or beneficial in the long run. Similarly, extrapolation from one “intended population” to the world as a whole is not generally a simple step for a man leading to a giant leap for mankind.

  • Heather Jones says:

    I had my covid booster by invitation at a covid centre on 30th sept and have just been invited by my surgery for the flu vaccine. As they have not been given at the same time how long interval should there be between the vaccines?

  • Anna says:

    For those who received J&J vaccine, there has been inexcusable lack of clear communication about the best way to proceed and ensure immunity. Could someone comment on the approvals for mixed vaccines?

  • Mrs Willis says:

    It is a travesty. Government has got the role out of booster vaccinations wrong. I cannot book until the 6 month date (but the number of days keeps changing from 182 to 189 to however many next) and then I believe there is up to a 2 month wait. Why can’t we book now and the system give us an appointment after the requisite number of days to prevent the 2 month+ wait? Winter is coming, I live down a 1metre drop drive and will not be able to get my car out to go 10 or so miles for a vaccination and at 71 I cannot dig the snow off the drive. I will not bother I think, IF I am ever invited.

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