Vaccine boosters may be needed this year (but then again ... )

Published: Jun. 23, 2021 at 1:34 PM CDT
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(CNN) – On Dec. 14, a nurse in New York became the first American vaccinated for COVID-19 outside of a clinical trial.

That was six months ago.

Now, the discussion is all about boosters.

Will we need them? And, if so, when?

Opinions vary.

“There will be a need for a booster somewhere between eight and 12 months,” said Dr. Albert Bourla with vaccine maker Pfizer.

“There is no set rule now that says in six months or in a year we’re going to require a boost,” according to Dr. Anthony Fauci with the National Institute of Allergy and Infectious Diseases.

“It’s frustrating because people want to know how long immunity lasts, but it’s just going to take time,” said Dr. Amesh Adalja at Johns Hopkins Center for Health Security.

Adalja has served on government panels on responding to public health emergencies.

For now, he’s looking for clues as to when booster shots will be needed.

“I want to know what’s happening to these patients clinically,” Adalja said. “Are they getting breakthrough infections, and are those breakthrough infections severe enough to land them in the hospital?”

With some diseases, like yellow fever, most people get lifetime protection from a vaccine.

But for others like influenza, yearly shots are needed.

For the family of coronaviruses, it varies.

“From the first SARS in 2003, it appears that those individuals who were infected naturally did develop long-standing immunity,” Adalja said. “It’s a little bit different with the community-acquired coronaviruses because they’re always causing common colds and they may be more tenacious to be able to cause reinfection.”

Booster studies are underway and there’s little evidence to suggest that new variants will be able to escape the protection they provide.

“I think it’s very hard for a virus to mutate in such a way, and to get the perfect mutations to be able to completely evade a vaccine to make it worthless,” Adalja said.

At the same time, there’s more and more good news about just how robust immunity to COVID-19 might be.

Six months out, both Pfizer and Moderna still have more than 90% efficacy against the virus.

For people who have been infected, there’s evidence of immunity a year later.

“The antibody arm that everybody knows about, and then there’s a whole other arm which is called cell-mediated immunity,” Adalja said. “You will find T-cells that are reactive to COVID-19 long after infection, and those may be really instrumental for how we determine when a booster is necessary.”

But some folks may benefit from a booster sooner than others, like immunocompromised people.

A recent study found that a third shot provided a boost to a small group of organ transplant recipients who had low antibody responses, including a third of them who had no detectable antibodies after the first two doses.

But for many of us, the benefit is less clear-cut.

It’s an issue that becomes even more complicated when you start to look around the world.

“If you’ve got this pandemic raging out of control in many countries where they can’t get single doses into people, it really is going to be difficult to justify giving people a third dose,” Adalja said.

Fauci has called the delta variant “the greatest threat” to progress against the pandemic.

Initial research suggests the current vaccines continue to provide protection against the variant.

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