Editor’s note: This story was updated at 4:28 p.m.
March 29, 2022 — The FDA said Tuesday that it approved fourth doses of COVID-19 vaccines for many Americans to protect the most vulnerable people against severe COVID-19 illness, hospitalization, and death.
According to an FDA news release, anyone over 50, and people over 18 who have gotten a solid organ transplant or have a similar level of immune risk, are now eligible for a second booster of either the Pfizer or Moderna vaccine.
“Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in the release. “Additionally, the data show that an initial booster dose is critical in helping to protect all adults from the potentially severe outcomes of COVID-19.”
“So, those who have not received their initial booster dose are strongly encouraged to do so,” he said.
The CDC followed suit hours later, recommending the fourth dose for the limited groups.
” This is especially important for those 65 and older and those 50 and older with underlying medical conditions that increase their risk for severe disease from COVID-19 as they are the most likely to benefit from receiving an additional booster dose at this time,” CDC Director Rochelle Walensky, MD, said in a statement.
According to CDC data, only 45% of people who are “fully vaccianted,” i.e., have received two shots of either Pfizer or Moderna or one shot of Johnson & Johnson, have gotten their first booster. That leaves challenges, Marks said later in a news briefing.
“I would urge people to get their first booster,” he said. “The third dose provided a differentially higher level of protection. It provided an additional benefit against hospital and death, and [the protection] is more durable.”
As for a fourth dose — or second booster — “there is evidence now that it can decrease the risk of hospitalization and death in older individuals – so we think this is something for people to consider doing,” Marks said.
Along with data submitted by each company, the FDA also reviewed data from an ongoing study in Israel assessing immune response to a fourth dose among health care workers at a health care center. All the workers received the Pfizer vaccine as their first booster shot. A total 154 people received a second booster with the Pfizer vaccine, while 120 others received a Moderna second booster.
The fourth dose increased neutralizing antibody levels against the coronavirus, compared to the levels people had 5 months after the first booster.
No new safety concerns were reported in any of the data.
The FDA says it will continue reviewing data on safety and efficacy of a second booster in other age groups.
The FDA’s committee of expert advisors meets April 6 and will discuss the path forward, Marks said.
“t would not be surprising if there is a potential need, there may be a need for people to get a booster in the fall and a more general booster campaign,” he said. “We may need to switch over to a different variant coverage.”
Eric Topol, MD, executive vice president of Scripps Research and the editor-in-chief of WebMD’s sister site Medscape, says a booster dose may not be completely necessary now, but it’s time is likely coming.
“It can certainly be deferred, but the question is when is the right time, and whether an Omicron-specific vaccines wil have any advantage over a 2nd booster directed at the original strain,” Topol says.