Science & Technology

Who needs COVID-19 boosters?

The first COVID-19 vaccines were barely in the arms of doctors and nurses in the United States before people started wondering what might come next. The vaccines would keep them safe, but for how long? Would variants make them less effective? Would everyone need a booster shot in a year or in two years? Could some people get away without that boost?

Those questions were front and center at this week’s meeting of the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP). The group isn’t making recommendations around COVID-19 vaccine boosters yet, but the discussion shows how leading health experts are thinking through the issues.

Here’s what we know so far: the vaccines authorized in the United States work extremely well at protecting the majority of people from the coronavirus. Protection seems to last a while. We’re not sure quite how long, but at the very least, it’s longer than the flu shot, which people get every year. The shots still work against coronavirus variants, even the fast-moving Delta variant.

But for some people, the vaccines don’t work. People who are immunocompromised, particularly people who have had organ transplants, often don’t produce antibodies after the regular doses of the COVID-19 vaccines. New research suggests that a third booster dose of an mRNA COVID-19 vaccine could give them more protection.

That’s the group the ACIP seems to think could be the first to get a booster because we have clear signals that it could help them. Then, after we learn more about how long protection lasts for everyone else — or if new variants emerge — experts could hammer out the details about boosters for the rest of us.

“There’s no data to support recommendations for booster doses at this time, except for the caveat in severely immunocompromised hosts who are not able to mount a strong response,” said Sharon Frey, an ACIP member and clinical director of the Center for Vaccine Development at Saint Louis University Medical School.

That data will come later. Ongoing studies are tracking the durability of COVID-19 vaccine protection, for example, and the CDC is watching to see if any variants evade the vaccines. Studies will check if people should get a third (or second, in the case of Johnson & Johnson) dose of a COVID-19 vaccine that already exists or a new shot with an updated form of the vaccine that targets specific variants.

“If we start to see an uptick in reinfections for people, or new infections in people who have been vaccinated, that’s our clue that we need to move quickly,” Frey said.

Looming over the ACIP’s discussion, though, was the troubling rates of vaccination in the US and around the world. Only 45 percent of the US population is fully vaccinated. Only 17.7 percent of the world is vaccinated. Unvaccinated people don’t need boosters; they need their first shots. Having more people vaccinated will slow the spread of the virus and prevent new variants. It’ll protect people who are immunocompromised, too: when everyone around them is far less likely to have COVID-19, they’re at a far lower risk of catching it.

Figuring out boosters is important. But getting unvaccinated people their shots — both in the US and around the world — is a critical way to protect everyone, said ACIP member Helen Talbot, an associate professor of medicine at Vanderbilt University. “Prior to going around giving everyone boosters, we really need to improve the overall vaccination rate,” she says.

Here’s what else happened this week.

Covid counting sees new era as threat shifts away from cases
In countries with widespread vaccination, the number of COVID-19 cases reported each day may not be the most important way to measure the pandemic. Immunizations mean cases are less closely tied to hospitalizations and deaths. (Todd Gillespie / Bloomberg)

Children’s Birthdays May Have Spread COVID Infections
Households where someone had a birthday were at a 30 percent higher risk of COVID-19 infection in the next two weeks than one with no birthday, a new study found. The results show the risk of social gatherings when the virus is widespread. (Rachel Nuwer / Scientific American)

Nearly all COVID deaths in US are now among unvaccinated
The vast majority of COVID-19 deaths in the US are now preventable. According to an Associated Press analysis, only about 0.8 percent of the deaths in May were in fully vaccinated people. (Carla Johnson and Mike Stobbe / The Associated Press)

What went wrong with CureVac’s highly anticipated new mRNA vaccine for COVID-19?
Like the Moderna and Pfizer / BioNTech vaccines, the CureVac shot uses mRNA. But it didn’t use a special chemical modification on one of the components of the genetic material, which may have made it less effective. (Jon Cohen / Science)

COVID vaccine research continues with help of trial participants
Proven COVID-19 vaccines are widely available to adults in the United States, but some people are forgoing the shots to participate in clinical trials for newer vaccines. (Hannah Weinberger / Crosscut)

The mRNA Vaccines Are Extraordinary, but Novavax Is Even Better
Novavax released its COVID-19 vaccine data later, so the excitement around its excellent findings was muted. But this shot might be even better than the mRNA vaccines. (Hilda Bastian / The Atlantic)

— Laura Holson writes in The New York Times about her recovery from Long COVID-19 and others who weren’t so lucky

To the people who have received the 2.8 billion vaccine doses distributed so far — thank you.

To the more than 179,587,904 people worldwide who have tested positive, may your road to recovery be smooth.

To the families and friends of the 3,891,685 people who have died worldwide — 602,562 of those in the US — your loved ones are not forgotten.

Stay safe, everyone.

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