CDC action heats up debate over vaccine boosters

The debate over COVID-19 vaccine boosters is intensifying after federal health authorities authorized a third dose of the vaccine for immunocompromised people last week.

Health experts said the decision made sense, but the move is likely to spur more confusion than clarity about the need for a booster dose. 

The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) made clear they authorized a third dose, not a booster, because the shots are considered part of the primary vaccine series. 

According to officials, data increasingly show that some people with compromised immune systems do not get the full benefit after just two doses.

The CDC had a very narrow definition of who is immunocompromised: it includes people undergoing treatment for solid tumors or blood cancers; organ transplant patients, including those who have gotten a stem cell transplant within the last two years; and people with advanced or untreated HIV.

Camille Nelson Kotton, a member of the CDC’s independent vaccine advisory panel, said the public should realize there’s “a pretty big distinction” between a booster dose for the general public and a third dose for people with moderate and severely compromised immune systems.

Kotton, who is the clinical director of immunocompromised care in the infectious diseases division of Massachusetts General Hospital, said booster doses are needed when people have an “appropriate” immune response that’s waned over time, like having tetanus boosters every 10 years.

“So far we are not recommending boosters for any population,” Kotton said. The public “should trust the science and trust the CDC guidance on this. And we would not recommend that people take matters into their own hands at this point.”

But even as experts say a broad push for boosters is premature and uncertain, conflicting messages from the drug industry and from abroad threaten to muddy the waters even further.

Israel launched its first-in-the-world booster campaign two weeks ago, targeting Israelis over the age of 50 who received their second Pfizer dose more than five months ago. 

On Monday, Prime Minister Naftali Bennett announced that more than a million Israelis have received a booster.

“Hundreds of thousands of people understand that our decision to give out a third vaccine is what these times call for,” Bennett said in a statement.

In the U.S., drug companies Pfizer and Moderna have said they will seek authorization for a booster shot.

Pfizer and BioNTech on Monday said they submitted early-stage clinical data to the FDA as part of their application for approval of a booster dose for anyone at least 16 years old. 

The companies said a booster dose of their vaccine generated “significantly higher neutralizing antibodies” against the original coronavirus strain as well as the beta and delta variants. 

“The data we’ve seen to date suggest a third dose of our vaccine elicits antibody levels that significantly exceed those seen after the two-dose primary schedule,” Pfizer CEO Albert Bourla said in a statement. 

However, the companies do not yet have the late-stage data to confirm those results. Bourla said results “are expected shortly” and will be submitted to the FDA and other regulatory authorities worldwide.

But Pfizer did not begin its global phase three study until July 1, with an estimated completion date of October 2022. The FDA usually requires phase three studies before granting approval. 

Despite the push from the manufacturers, federal health officials do not appear to be ready to endorse booster shots for the general public. 

Last month, the FDA and CDC quickly pushed back in a rare joint statement after Pfizer suggested booster shots, saying they were not currently needed. 

Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, said he understands that people are anxious, and acknowledged the CDC’s distinction between “third shot” and “booster” might get lost on the general public.

“People kind of just do what they want to do. Witness that 25 to 30 percent of people in this country who just say ‘no, thank you,’ for the vaccine. It’s frustrating. You can do your best to educate, but it’s hard,” Offit said.

Offit said the focus instead should be on making sure as many people in the U.S. get vaccinated as possible, and sending significantly more doses overseas.

“That’s why we still are talking about masks and boosters and isolation and quarantine, because we have a critical percentage of people in this country that haven’t been vaccinated. That should be the focus in this country because that’s why the virus is spreading,” Offit said.

“The booster dosing issue is really trivial in terms of really getting on top of this pandemic.”