Breaking down the debate over booster shots

As tempers flare over who needs the COVID-19 vaccine and when, core discussions are being lost

September 15, 2021 4:45 am

A nurse draws vaccine doses from a vial as Maryland residents receive their second dose of the Moderna coronavirus vaccine at the Cameron Grove Community Center on March 25, 2021, in Bowie, Maryland. (Win McNamee/Getty Images)

For days, news outlets have lit up with the growing controversy over booster shots.

The question: “Do Americans need booster shots, and, if so, when?”

On the one hand, President Joe Biden announced his administration would aim to secure booster shots by the end of September. However, these plans were announced prior to a completed Food and Drug Administration review, prompting tensions and two 30-year career FDA scientists — both of whom were instrumental in reviewing the original COVID-19 vaccine authorizations — to submit their resignations. The same two scientists later co-authored a research publication outlining the status of boosters and warning against political interference.

Meanwhile, top officials at the Centers for Disease Control and Prevention are said to be in conflict with the White House and FDA on the matter, and the World Health Organization has asked wealthier nations — including the U.S. — to refrain from administering booster shots through the remainder of the year, even though Biden is forging ahead.

Is it any wonder why everyone is confused?


As if the mixed messages weren’t bad enough, Gov. Jared Polis fanned the flames at a Monday press conference.

In one of his more blatantly hyperbolic statements to date, the governor openly rejoiced over the departure of the two prominent FDA scientists, calling them “disgraced” and claiming they have “blood on their hands” for delaying the boosters. He also stated FDA public servants needed to get out of their “ivory towers” — a loaded set of criticisms coming from a man in a mansion who still refuses to enact even basic mask mandates.

Alas, let’s skip the politics and get to the heart of the debates.

Ultimately, the scientific discussions of boosters can be broken down into three core areas: Does the booster shot demonstrate enough clinical benefit to be issued now? Would it be better to pursue variant-based boosters? Is there more to be gained by prioritizing vaccine doses for the unvaccinated population globally?

The question of clinical benefit and safety is specific to boosters. We know the vaccines have been proven safe and effective for single- or two-dose series. They also greatly reduce the risk of hospitalization and death, including against the delta strain. The pause is exclusively due to a lack of robust data that demonstrates if there is enough clinical reduction in hospitalizations and deaths to warrant the risks of increased symptoms with a booster, as well as a strong enough benefit to support the additional distribution of a limited vaccine.

In this standard evaluation, it’s critical to remember that the vast majority of transmission for COVID-19 is still driven by unvaccinated people. For boosters, this means there is essentially a higher bar for clinical gain to make any drawbacks worth it — and we simply don’t have enough of this data yet.

Next, the discussion of variant-based boosters reflects a unique opportunity to conduct clinical trials on boosters that would be tailored to current and future variants. This means we would study the next generation of boosters while we still have protection from the current ones. This is similar to the approach used for influenza.

Finally, perhaps the most compelling question is that of ethical distribution abroad. Since we know that by far the most clinical benefit is seen by increasing overall vaccination rates, the best chance to reduce cases and lower the likelihood of further variants is to increase overall vaccinations globally. This is why the WHO has requested wealthy nations hold off on boosters — therefore prioritizing doses for less wealthy nations — and why there is more of an argument to be made for vaccine mandates in America than there might be for booster shots.

All this said, there’s one more thing that’s critical in clearing up why some people might need a third shot now while others don’t.

When we talk about boosters, scientifically that refers to a person who has received a full series of a vaccine and, after achieving full protection, has seen that protection wane.

In contrast, some people — particularly those who are immunocompromised — would have gotten the same series of shots, yet they were unable to achieve the same level of protection as the general population. For these people, a third dose is not technically a booster but rather an additional dose in the necessary series to gain full protection. This small terminology difference has serious implications when considering who gets doses first.

Personally, as much as I’d selfishly love a boost, Polis might suggest I’m also a scientist with blood on my hands for accepting the argument for full series doses, vaccine and mask mandates and global distribution now, and the pursuit of variant-specific boosters slightly later.

Then again, governor, how many lives could have been saved with a simple mask mandate?


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Trish Zornio
Trish Zornio

Trish Zornio is a scientist, lecturer and writer who has worked at some of the nation's top universities and hospitals. She’s an avid rock climber and was a 2020 candidate for the U.S. Senate in Colorado.