SCOTT SIMON, HOST: Dr. Paul Offit has advised the FDA during the vaccine-approval process. He's director of the Vaccine Education Center at the Children's Hospital of Philadelphia. Dr. Offit, thanks so much for being with us.
PAUL OFFIT: Thank you.
SIMON: The Moderna and Pfizer vaccines have a much higher effective rate - don't they? - in the mid-90s. So what makes the Johnson & Johnson version a good idea at just 66%?
OFFIT: Well, the Moderna and Pfizer vaccines were tested in the U.S. only. The Johnson & Johnson vaccine was also tested in several countries in South America, as well as Mexico and South Africa. So it's not exactly the same population. So it's sort of comparing apples to oranges. Also, the strains that were circulating in South Africa is primarily the South African variant, and the strain circulating in Brazil is primarily the Brazilian variant. So there were different strains, really, that this vaccine was tested against.
SIMON: I gather from reports that some of your fellow panelists asked whether Johnson & Johnson's vaccine might be more effective if it were given as two shots, not just one, and that the company is studying this. What's your view on that?
OFFIT: Right. So if you look at the studies they did, the preclinical studies they did in non-human primates as well as the Phase 1–2a studies they did in people, what they found was that second dose did increase the titer or the quantity of virus-specific neutralizing antibodies, suggesting that it might be more effective. It's very effective, though, at preventing severe disease after a single dose. And it induces the kind of response, so-called cellular immune response, that looks like it's going to have fairly long-lived memory, which is all good.
But that second dose may be more effective. I think we'll probably know that by the second half of this year, in which case, then one could get a booster dose. But this certainly provides protection against what you care about, which is hospitalization, ICU admission and death. And it's virtually 100% effective at doing that.
SIMON: And if authorization follows soon, when might the vaccine come to pharmacies and other vaccination sites, and how much?
OFFIT: Right. So it follows the pattern of what we saw with the Pfizer and then Moderna vaccines. Usually the FDA advisory committee in which I sit makes a recommendation. The FDA usually follows that recommendation within a day or two. And then it goes to the CDC, which then makes their recommendations about which group or groups might best benefit from this vaccine. That all happens within about a five-day period. And then the vaccine can sort of roll off the assembly line into the arms of the American public.
SIMON: Dr. Offit, you're a pediatrician. What do you tell parents who are very eager for a vaccine for their children and who are concerned, for example, about the apparent increase in multisystem inflammatory syndrome in children, which is rare, but a serious disease that's connected to COVID?
OFFIT: Well, it's certainly worth trying to prevent this disease in children. Although children are obviously much less likely to die from this virus, still, the number of children who died last year from SARS-CoV-2 was roughly the same number that die every year of influenza. Plus, as you say, it can cause this sort of longer-term multisystem inflammatory disease. So anything that causes children to suffer or be hospitalized or die is worth preventing.
But right now, we still need to figure out what the right dose is. And I think what's going to happen now over the next few months is that children between 12 and 18 years of age will be studied to make sure that the dose is right, that it induces a consistent immune response. It's not going to be the same kinds of studies you just saw for Pfizer and Moderna and Johnson & Johnson, which were studies of 30 to 45,000 people to see whether it was effective, because children don't get that sick, so it would be hard to do those studies. And those studies are in the midst of being done.
SIMON: Let me ask you about the AstraZeneca-Oxford University vaccine. Do you have any doubts about it? Canada's just authorized it, but there are questions about it in the U.S., aren't there?
OFFIT: Yes. Now, I think they have sort of moved forward in fits and starts, really right from the beginning, even with their Phase 1 studies. But the good news is right now, the AstraZeneca product is being tested as a two-dose vaccine in the United States. And presumably in the next few months, we'll see whether or not it works and whether it's safe. So we won't have to rely on the U.K.-Brazilian data, which I think were sporadic and somewhat difficult to interpret.
SIMON: Dr. Paul Offit is a member of the FDA's vaccine advisory panel. Thanks so much for being with us.
OFFIT: Thank you. Transcript provided by NPR, Copyright NPR.
