Do We Need a Fourth Covid Shot?

The reports are conflicting but I'd bet on Yes.

The award-winning NYT health reporter Apoorva Mandavilli offers an encouraging assessment: “Got a Covid Booster? You Probably Won’t Need Another for a Long Time.”

As people across the world grapple with the prospect of living with the coronavirus for the foreseeable future, one question looms large: How soon before they need yet another shot?

Not for many months, and perhaps not for years, according to a flurry of new studies.

Three doses of a Covid vaccine — or even just two — are enough to protect most people from serious illness and death for a long time, the studies suggest.

“We’re starting to see now diminishing returns on the number of additional doses,” said John Wherry, director of the Institute for immunology at the University of Pennsylvania. Although people over 65 or at high risk of illness may benefit from a fourth vaccine dose, it may be unnecessary for most people, he added.

Federal health officials have said they are not planning to recommend fourth doses anytime soon.

The Omicron variant can dodge antibodies — immune molecules that prevent the virus from infecting cells — produced after two doses of a Covid vaccine. But a third shot of the mRNA vaccines made by Pfizer-BioNTech or by Moderna prompts the body to make a much wider variety of antibodies, which would be difficult for any variant of the virus to evade, according to the most recent study, posted online on Tuesday.

The diverse repertoire of antibodies produced should be able to protect people from new variants, even those that differ significantly from the original version of the virus, the study suggests.

“If people are exposed to another variant like Omicron, they now got some extra ammunition to fight it,” said Dr. Julie McElrath, an infectious disease physician and immunologist at Fred Hutchinson Cancer Research Center in Seattle.

What’s more, other parts of the immune system can remember and destroy the virus over many months if not years, according to at least four studies published in top-tier journals over the past month.

But, alas, this contradicts quite a bit of other reporting, including one from NYT (“New C.D.C. data adds to evidence that boosters’ protection against severe Covid plunges after four months.”) just a few days ago.

Covid booster shots lose much of their potency after about four months, raising the possibility that some Americans — specifically those at high risk of complications or death — may need a fourth dose, data published on Friday by the Centers for Disease Control and Prevention suggest.

Preliminary research from Israel and Britain has hinted that protection from booster doses declines within a few months. The data released on Friday offer the first real-world evidence of the mRNA shots’ waning power against moderate to severe illness in the United States.

The analysis did not include a breakdown by age, and the researchers could not distinguish between a booster shot or a third dose given to an immunocompromised person as part of the primary series.

The study focused on people who sought medical care for symptoms of Covid, so if that population was skewed toward older adults or those who have weak immune systems, the booster shots may have seemed less effective than they really are.

Other studies have shown that while vaccines may lose some ability to prevent severe illness and hospitalization in adults older than 65, they remain highly protective in younger adults in good health. Federal health officials will need to know who exactly is at high risk even after three doses before considering recommending a fourth shot.

“There may be the need for yet again another boost — in this case, a fourth-dose boost for an individual receiving the mRNA — that could be based on age, as well as underlying conditions,” Dr. Anthony S. Fauci, the Biden administration’s top Covid adviser, told reporters on Wednesday.

The C.D.C. has previously published data showing that second and third doses of the Moderna and Pfizer-BioNTech vaccines were less effective at fending off the Omicron variant than the Delta variant. Third doses enhanced that protection, at least in the short term.

And this from WSJ just this weekend (“FDA Eyes Second Covid-19 Booster Shot“):

U.S. health regulators are looking at potentially authorizing a fourth dose of a Covid-19 vaccine in the fall, according to people familiar with the matter.

The planning is still in early stages, and authorization would depend on ongoing studies establishing that a fourth dose would shore up people’s molecular defenses that waned after their first booster and reduce their risk of symptomatic and severe disease, the people said.

The Food and Drug Administration, however, has begun reviewing data so it can make a decision, the people said.

The thinking among regulators is that the agency would look at authorizing a second booster dose of the messenger RNA vaccines from Pfizer Inc. and partner BioNTech SE and from Moderna Inc., one of the people said.

Among the issues that need to be resolved, the person said, are whether the second booster should be authorized for all adults or particular age groups, and whether it should target the Omicron variant or be formulated differently. Whether the fourth booster could ultimately be the start of an annual Covid-19 vaccination is also under consideration.

No decision is final, and it could be necessary to make booster shots available earlier if a dangerous, elusive variant appears, the person said.

Offering a second booster dose, one of the people said, may make sense in the fall because many people get their annual flu shots then and so might be more receptive to getting vaccinations.

Potential obstacles to the effort are that many people are fatigued with vaccinations after getting initial doses and that others are hesitant to get the shots.

I would frankly be surprised if annual boosters didn’t become the norm—especially for elderly and other high-risk individuals. And, yes, it probably makes sense to pair it with the flu vaccine to develop the habit. (Although, ironically, both myself and my 13-year-old got our flu shots, which we do sporadically, only because we were getting our booster, anyway, so I opted us in for both at the same time.)

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James Joyner
About James Joyner
James Joyner is Professor and Department Head of Security Studies at Marine Corps University's Command and Staff College. He's a former Army officer and Desert Storm veteran. Views expressed here are his own. Follow James on Twitter @DrJJoyner.


  1. Scott says:

    I got my booster on Oct 21. So it’s been 4 months. To me, the decision tree here is pretty simple. Is the 4th booster safe? Yes? Get a booster regardless of a marginal increase in effectivity. Seems like low cost insurance to me.

  2. James Joyner says:

    @Scott: It depends on how marginal, no? Getting the shot is not without cost, in that, at minimum, it means a couple of days of soreness and often what amounts to a short-lived bout with the flu.

  3. Sleeping Dog says:

    A friend, who is immunocompromised has received his 4th shot, but he is the only one that I know of. I agree that for at least a subset of the population, annual boosters will be recommended.

    Today’s NYT article discussing how T-cells can provide long term protection is encouraging. A key point that wasn’t necessarily featured is the explanation as to why it has taken so long to recognize the benefits of the T-cells.

  4. Not the IT Dept. says:

    @James Joyner: “Getting the shot is not without cost, in that, at minimum, it means a couple of days of soreness and often what amounts to a short-lived bout with the flu.”

    It’s great to live in the First World, isn’t it? Our forefathers would have been proud of a sore arm, after walking through the blizzard to get their shots, up hill, both ways.

    BTW, not everyone gets the short-lived bout afterwards. My wife and I were fine all three times. None of my kids reported anything to us about sore arms or flu-ish afterwards.

  5. Kathy says:

    There seems to be something about respiratory viruses that renders vaccines less effective as compared to other diseases. Or maybe it’s the lack of near universal vaccination for these viruses. either way, it’s worth looking into.

    If annual or twice-yearly boosters are needed, fine. It’s a small price to pay. For the record, my first dose of Pfizer had no side effects at all. The second gave a sore arm for a day or two. The AstraZeneca booster gave me a sore arm, chills, and fever.

    I find the last unsurprising, as it uses a virus vector to infect cells to get them to make spike proteins. A reaction by the innate immune system is to be expected.

    A key point that wasn’t necessarily featured is the explanation as to why it has taken so long to recognize the benefits of the T-cells.

    Because humans have an allergy to nuance and a strong preference for simplicity. Antibodies are simple (and easy to measure, which is another bias). T cells are complicated, beginning with the variety of T cells that exist.

  6. Daryl and his brother Darryl says:

    Sign me up as soon as it is available.

  7. Scott says:

    @James Joyner: Despite the fact that my mental age is about 35 and I think I’m still a hunk, my body is nearing 68. And, while still definitely a hunk ,unfortunately, it is not in a good way. I don’t get much reaction to any vaccines, so it’s still a no brainer.

  8. MarkedMan says:

    @Scott: Bear in mind that there is evidence for certain vaccinations that getting too many boosters start to result in reduced efficacy.

  9. Just nutha ignint cracker says:

    @James Joyner: Maybe for you. This asthmatic who gave himself allergy shots for 10 or so years has felt no ill effects from any of the shots so far. They don’t even sting when they go in.

  10. Kathy says:

    BTW, remember the news a few weeks ago that an Omicron specific shot was being tested by Pfizer, and we’d get results by March?

    The variants are rising and falling too fast. My very non-expert opinion is we’ll wind up with polyvalent yearly boosters, much as we have for flu.

  11. Jen says:

    I posted this link over in the open thread, but it’s probably more relevant here.

    A pivotal study that looked at health records of more than 153,000 U.S. veterans published this month in Nature Medicine found that their risk of cardiovascular disease of all types increased substantially in the year following infection, even when they had mild cases. The population studied was mostly White and male, but the patterns held even when the researchers analyzed women and people of color separately. When experts factor in the heart damage probably suffered by people who put off medical care, more sedentary lifestyles and eating changes, not to mention the stress of the pandemic, they estimate there may be millions of new onset cardiac cases related to the virus, plus a worsening of disease for many already affected.

    “We are expecting a tidal wave of cardiovascular events in the coming years from direct and indirect causes of covid,” said Donald M. Lloyd-Jones, president of the American Heart Association.

    One of the people profiled is young, and was fully vaccinated and boosted and is still dealing with long-covid issues:

    Zaza Soriano, 32, a software engineer from Millersville, Md., who works for a NASA subcontractor, got covid right before Christmas despite being fully vaccinated and boosted, and since then, her blood pressure has remained very high with the bottom number, or diastolic pressure when the heart rests between beats sometimes as high as 110 when it should be lower than 80. She also has brain fog and her joints ache.

    I will get a booster if/when I am instructed to, immediately.

  12. MarkedMan says:

    @MarkedMan: From NBC News:

    “The question is, if you keep priming and boosting with a strain, which is basically to make an immune response against the ancestral strain, will that limit your ability then to make an immune response to a virus, which is very much different than the ancestral?” said Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia.

    Offit is describing a phenomenon immunologists call “original antigenic sin” in which the body’s immune system relies on the memory of its first encounter with a virus, sometimes leading to a weaker immune response when it later encounters another version of the virus.

    Vaccines can activate this phenomenon, too, said Offit, also a member of the Food and Drug Administration’s vaccine advisory committee. An example is with the human papillomavirus, or HPV, following the release of an updated vaccine that targeted nine strains of the virus instead of just four in the initial shot, he said.

    “If you got HPV4 and then got HPV9, knowing that the four strains in [HPV]4 were also in [HPV]9, you had a very good immune response to the four strains, but you didn’t have as good as an immune response to the other five strains,” he said.

    Theoretically, it could apply to Covid, too, Offit said.

    He said that some experts have argued it may be better for those not at high risk of severe disease to wait to get a booster until a variant-specific option is available.

    No matter how much we want this calculus to be simple and for the CDC to instantly have scientifically sound advice, there are a lot of variables at play. And the medical profession takes “first, do no harm” very seriously.

  13. Monala says:

    I received the J&J shot originally, and then the Moderna booster. So I’ve only had two shots. Because I also had Covid over Christmas, my doctor says I don’t need a third shot yet, even though I am immunocompromised. My Covid bout was mild, like a bad cold, and so far I haven’t seen any post-Covid after effects.

    By the end of March, I will be both 6 months post booster, and 3 months post Covid, so I will take action then if my doctor won’t.

  14. Kathy says:


    It seems what we need is a time machine. That way someone can go to 2025, see all the data on COVID, have all the genetic recipes for all the variants, then go back to 2019 along with 25 billion doses of mRNA vaccines that 40% of the population won’t take.

    Until Doc Brown solves the Flux Capacitor problem, then, wear a mask and get all the vaccines offered.

  15. MarkedMan says:

    @Kathy: I could use that for raising kids too! It always seemed like I finally learned how best to deal with kids of a certain age 3 or 4 years after mine aged out.

  16. Hal_10000 says:

    There’s no contradiction in the studies. The bottom line is this:

    1) Antibodies wane after getting the COVID shot over a period of about six months.
    2) However, your body’s T- and B-cells remember the virus and can ramp up response very fast
    3) Even better, your T- and B-cells do some of their own experimentation, improving and modifying the antibodies, which can sometimes help counter future variants even better.

    I expect we will get an annual COVID shot to boost antibody levels going into cold/flu/COVID season, especially for those who are at risk. But these studies suggest the vaxxed have long term protection from serious illness and death.

  17. Bob@Youngstown says:

    Vaxxed and boosted ! No adverse reaction, tenderness at the injection site for less than 16 hours.

    I trust my primary care physician to guide me to make good decisions that will do me no harm. I trust that my PCP is better informed and educated in medical matters than I. He certainly knows my body better than the CDC or some random poster on the infernet.

    So, when I see my doctor in April, if he recommends getting a 4th Moderna, I’m all in!