https://www.cidrap.umn.edu/covid-19/podcasts-webinars/episode-38
Chris Dall: [00:44:18] So there's been some discussion and debate about lengthening the amount of time between vaccine doses in an effort to get more initial doses into arms, which the United Kingdom is doing, but the Food and Drug Administration and the World Health Organization have both come out against. Mike, what do you make of this idea?
Michael Osterholm: [00:44:36] We all want more vaccine. We know that given the projections of those companies that have licensed products or likely will be licensed in the near term, that we're not going to have nearly enough vaccine for the world in the next year. And even in a country like the United States, it could be the second or third quarter before we see sufficient quantities of the vaccine to get everyone vaccinated in the country. Again, assuming we can get them vaccinated. So it makes sense that we're trying to find ways to stretch the vaccine, and one of the challenges has been having a two dose vaccine, is originally Operation Warp Speed demanded that for every dose that goes out, a dose gets saved without accounting for, with increasing production, could you vaccinate everybody today on first dose? And as production increases, continue doing first dose, but also then have enough excess capacity to then use that to go back and for dose two for everybody behind you so that as production ramps up that be done. I have to say, I'm very concerned about changing any of the recommendations how the vaccine be administered without additional scientific evidence. We need the scientific evidence. For example, if one looks at the studies that were done, it is absolutely true with both Moderna and the Pfizer vaccines, there was evidence of some protection within seven to 10 days of the first dose of vaccine. The problem is, if you look at the antibody from those studies, it largely was a non neutralizing antibody, the kind that we need to have to, in fact, actually be certain that we're getting good protection against the virus. We don't know, if we didn't give a second dose, how long after that that that first dose may protect you for. So the second dose is clearly what we call a boost on the prime, but it's also one that may take you to the next threshold where it's not just about your durability of protection, but even the extent of your protection. I am particularly worried about that in those high risk groups for serious illness with covid-19. Take a step back and look at influenza vaccine. I'll grant you, these are two totally different viruses, two totally different vaccines. It's notable that those individuals who are at highest risk for serious covid-19 related disease, including death, are the same people who are at increased risk for severe disease or even death from influenza. What have we learned from influenza vaccines? That by adding more antigen, or more of the vaccine, to the shot, adding adjuvants, or chemicals it can help boost the response, have meant that there's an improvement in these people that don't respond as well, who also have a much higher risk of serious disease. We don't know in the high risk groups of individuals for covid-19 that the second dose doesn't provide that same kind of boost phenomena. So, you know, I think we all have to be open minded. We have to understand that it would be great if we could get more vaccine quicker. But it's got to be based on the science. And we can't just go knee jerk and say, "Oh, well. You know, we got some protection with dose one". That may be a big problem. The brits obviously have made a decision to go ahead and do the one dose with a 12 to 18 week postponement for dose two so they get more people vaccinated with dose one. I'd love to see the scientific data that allowed them to make that decision. We already know that the AstraZeneca vaccine has some of its challenges on its original data presentation, whereby looking at lesser doses and more doses and the lesser dose being an accident in terms of the study design showed somewhere between 60 percent and up to 90 percent protection. Well that 60 percent's concerning to me, particularly now for the single dose, what does that mean? So I would just come back and say that the Food and Drug Administration put out a letter this week clearly laying out the justification for sticking with the current approach. I support it completely. Many of my colleagues who work in this area support it. And I would be the first to say again, if we can find a way to extend the vaccine supply, do it. One of the areas we're looking at right now is with Moderna, the vaccine. There may be an opportunity there because we are using one hundred microgram dose right now as the approved product. And there was actually an arm in the trial that used a 50 microgram dose and found virtually the same results as the hundred microgram dose. With that information, now it's science based information, ee could say, well, let's basically use half the amount of the Moderna vaccine and double the supply and anticipate getting the same results. So at this point, I would just urge us to stick with the science. We want more vaccine as quickly as we can, but the science has got to win out.
FDA Statement on Following the Authorized Dosing Schedules for COVID-19 Vaccines | FDA