Why Are Top Scientists Opposing COVID Boosters?

The history of science is chock-full of disagreements. Taking a contrarian view has been instrumental in quite a few scientific advances through the years. It shouldn't come as a surprise then that some top scientists have opposed booster shots for COVID-19 vaccines. In this Motley Fool Live video recorded on Sept. 15, Motley Fool contributors Keith Speights and Brian Orelli discuss what's behind this opposition.

[Note: This recording was made prior to the U.S. Food and Drug Administration approving a booster for the COVID-19 vaccine marketed by Pfizer (PFE 0.15%) and BioNTech (BNTX 0.32%).]

Keith Speights: Probably one of the biggest COVID-19 stories right now is that a group of international scientists, including notably two top outgoing FDA officials, have concluded that boosters are not needed, at least for now. There was a report, a paper published in The Lancet on Monday, that detailed their conclusion.

Brian, what's behind this reasoning, and does it mean anything for the top vaccine stocks?

Brian Orelli: The basic idea here is that you might get sick because your antibody levels have waned over time, but you have other defenses that can kick in eventually and so you're not likely to get that sick, you're not likely to have severe disease. They're arguing that the risk of the side effects from the vaccine don't justify the benefits from the booster because whatever rate you're going to die from it, you compare that to the rate of dying from the risks of the side effects, it's hard to quantify.

Maybe I'll give you an example. Let's take the common cold. If I could make it so you never got the common cold but there was a 5% chance of dying, I think most people would say, [laughs] I'm not going to do that. I don't like getting the cold, but I don't like a 5% chance of dying.

But then if I drop it 0.5%, probably not, 0.05%, probably not because the common cold's not going to kill you. But at some point, we've got an infinitesimal chance of you dying versus you not having to deal [laughs] with the cold for the rest of your life and especially if you've got a long life ahead of you. At some point, it's worth taking that risk. But it's hard to say [laughs] exactly where that should be.

This example is just a two-sided example. There's a lot more that goes into questions for boosters. You got mild versus severe disease and you've got multiple different side effects working into the potential. I think it's a difficult calculation to make, but they've made it [laughs] and they've said that they've come on the side of the fact that the boosters aren't worth it right now.

Then they caveat that with they could be needed later if the antibodies continue to wane or if the rest of your immune system wanes or if we had a variant that's even stronger that might skew it ahead, skew the risk-reward profile toward boosters. I'd also note that the WHO officials were also involved in writing this article and they're obviously more concerned with the disease globally.

Their concern that if we use boosters then if we are supply constrained, then those boosters won't be available for countries with low vaccination rates elsewhere. This isn't just an ethical argument over who should get the boosters and arguably vaccinations elsewhere will help people in the U.S. because the rampant spread of the virus elsewhere increases the likelihood of new variants that can then come back into the U.S. and if they're even more deadly, can overpower the boosters that we got.

There's that argument, too, that we could use those boosters to slow the spread, which might actually help us more than giving us the boosters will. [laughs] There's a lot of things that factor in here.

Shares of Moderna (MRNA 0.28%) and BioNTech dropped on the news when this article came out and that seems completely reasonable. The valuations of these companies assumed that the boosters will be needed and I'd argue that not only are they assuming that a third booster shot will be needed, but they are really expecting a fourth and fifth and so on to really justify their evaluations. Especially Moderna's, it's gotten above $170 million or so.

Speights: Brian, what's your take, just your opinion. Is there enough evidence, do you think, for the US to move forward with booster doses at this point?

Orelli: I think there's probably enough evidence for some populations, populations that are sicker, that are more likely to die. If you get the disease, it's more likely to progress to severe disease. I think there's probably enough evidence to justify boosters, but I think in the healthy people, generally, I think the jury is still out and leaning toward not requiring the boosters.

We'll have to wait and see what the FDA Advisory Committee does on Friday and then whether the FDA makes a fairly quick decision. Then even then, they have to approve the boosters, but then it goes to the CDC and the CDC's vaccine committee, which is not an advisory committee, it's a mix.

I guess they make a recommendation but it's part of the CDC. That's what's going to be the law of the land and so doctors are going to follow the CDC's recommendation. The FDA could approve the boosters and then the CDC could come out and say, yeah, we only think they should be using a certain population or we don't think they should be used right now, but we'll continue to monitor the situation. Even the FDA decision is not going to be the final event here in whether we need boosters.