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In this video interview, Paul Offit, MD, of Children's Hospital of Philadelphia, discusses the rationale behind the CDC recommendation for a yearly COVID booster, and how U.S. policy differs from other countries' recommendations. Offit is also a member of the FDA Vaccines and Related Biological Products Advisory Committee.

The following is a transcript of his remarks:

There is a vaccine available this year to prevent COVID that is a monovalent vaccine, which means it contains one strain. That strain is the XBB.1.5 strain. So who should get it?

Well, a number of countries have weighed in on this: the , , the , , as well as the . Their recommendation is a targeted approach, meaning let's prevent [infection in] those who are most likely to suffer serious disease -- and by serious disease, I mean, be admitted to the hospital in the ICU or die -- because that's the goal of this vaccine, to prevent serious illness.

Those groups were people who are elderly; people who have multiple comorbidities like obesity, diabetes, chronic lung disease, chronic heart disease; people who are immune compromised -- typically because they're taking medicines that suppress their immune system -- and pregnant people. That's what these countries decided to do.

Now, the United States made a different decision. What they decided in the past week is that they want to offer this vaccine to . So why? Why are we then taking a position different from those countries?

During the committee hearing, which was last week, there was basically a 6-hour discussion where they brought up a number of points to try and make a case for a broader recommendation.

One was the notion of obesity, and so what they presented were data that about 70% of the country is either obese or overweight. Now, being overweight is not a risk factor. Obesity is, and less than half the country is obese, probably . You could make the argument that if you're not obese, that doesn't mean that you should get this vaccine, so why say vaccinate everybody just because a fairly large percentage of the country is obese?

The second reason was long COVID. Wouldn't it make sense to give an additional dose to prevent your chance of having long COVID, which is characterized by fatigue, headache, brain fog, muscle ache, etc.? Are there data to support that additional doses beyond what most people have already gotten -- because most people at this point have already gotten a few doses plus a natural infection, which is defined as hybrid immunity, and most of this country at this point has that; we have a high level of population immunity. Does an extra dose make a difference?

This hasn't been well-studied. And the term "long COVID" is probably more than one thing, and it's variously defined, but there was that did look at this. What they did was they looked at people who didn't get any vaccine and then got COVID and found that the instance of long COVID was 42%.

Then they looked at people who'd gotten one dose of vaccine then got COVID, and the incidence of long COVID there was 30%. So it went from 42% to 30%. Then they looked at people who'd gotten two doses of the vaccine and got COVID, and the instance of long COVID was 17%. So it went from 30% to 17%. Then those people who'd gotten three doses of vaccine and then got COVID, and the incidence of long COVID went from 17% to 16%. So no difference. That additional dose beyond two doses, at least in that study, didn't make a difference.

The third reason that was argued for here, which I think didn't make a lot of sense, was that if you look at the group most likely to be hospitalized, not surprisingly, that group was over 75 years of age. The group that was second most likely to be hospitalized was children between 6 months and 4 years of age. Most of whom, or many of whom, were otherwise healthy.

So why that group? And the answer is that children in general are the least vaccinated group, and children less than 4 years of age are the least of the least vaccinated group, so about . That's why they're getting hospitalized. It's not because they need a booster dose, it's because they need to be vaccinated in general.

Instead of trying to argue for a booster dose for that 10%, I think we should be arguing for a vaccine for the 90%. So I don't support the notion of trying to vaccinate everybody, because I think we will have the biggest impact by focusing on high-risk groups.

Now the question is, how does this get communicated? Some people will argue, reasonably, that if you have a more nuanced message, that it will be a garbled message that won't be understood by the general public. But we certainly have nuanced messages for other things.

For example, there is now a monoclonal antibody available to . All babies less than 8 months of age are recommended to receive this monoclonal antibody. It's long-acting. It's called nirsevimab, otherwise known as Beyfortus. But for the second year of life, the 8- to 19-month old, that's only recommended for high-risk groups. That is a nuanced message. We could make it easier by saying 'Everybody should get nirsevimab for the first two RSV seasons,' but we didn't say that. We said 'Here's who should get it in the first season. Here's who should get it in the second season.'

So we do have targeted recommendations, and I think we should trust the American public to be able to understand the thinking behind why we make various recommendations.

It will be interesting to see how this will play out this winter, because the way that I think some people understand this vaccine is that it's like the flu. We have likened this to flu. Certainly, it's important to get a flu vaccine every year. Everybody over 6 months of age should get a flu vaccine every year.

Now, the flu vaccine is strain specific. If you are wrong -- and the FDA vaccine advisory committee sits down in March of every year, and tries to figure out what strains are going to come into this country and they get that information based on countries that have winters that precede ours as to what strains are likely to come in -- if you miss with flu, a miss is a mile. You pick the wrong strain and you're in trouble. That's what happened. If you look at those years where we missed, protection against severe disease was . That's not good.

That's not this virus. That's not SARS-CoV-2. And the reason is that protection against severe disease is largely mediated by T-cells, memory T-cells. It takes time to develop severe disease. It takes 10, 14 days to develop severe disease. So if you have memory cells, that's plenty of time for those memory cells to become activated, differentiate, and make T-cells like cytotoxic T-cells, which kill virus-infected cells.

The good news about this particular immunological component, T-cells, is that the parts of the virus that are recognized by T-cells are , with 80-85% conservation from the original strain, the ancestral strain, to the current strains like EG.5 or BA.2.86. The T-cell epitopes haven't dramatically changed, and that's why you're still protected against severe disease.

In any case, I think it's very important for people who are in high-risk groups to get this vaccine, and certainly for people who live in the home of someone who's immune compromised or who work in a nursing home. I think anybody who wants to get a vaccine certainly should be encouraged to get it, but I'm not sure why we made that recommendation. Maybe it's because we have, to some extent, a dysfunctional healthcare system and we fear that by making a targeted recommendation, private insurers won't then cover those other people who live or work in nursing homes, or who live in the home of someone who's immune compromised. Maybe that's the reason.

But we are in many ways different than many other countries in terms of how we recommend this vaccine.

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