An advisory panel from the Centers for Disease Control and Prevention on Thursday recommended updated versions of Pfizer-BioNTech and Moderna’s Covid boosters, a critical step before the shots can be administered.
The favorable votes came after an extensive discussion among members of the Advisory Committee on Immunization Practices, many of whom expressed concerns about the lack of clinical data in humans on the updated vaccines.
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The recommendation is in line with guidelines from the Food and Drug Administration, which on Wednesday authorized the modified shots for teens and adults. Pfizer’s booster was approved for individuals 12 years of age and older; Modernas for persons 18 years and older. People are eligible for a booster at least two months after the second dose of their primary series or last booster injection.
The director of the CDC, Dr. Rochelle Walensky, is expected to give its final approval soon, a step that will allow vaccinations to begin.
However, the booster campaign isn’t expected to get underway on a large scale until next week, as the federal government works to distribute the new shots to states in the coming days. Vaccination sites and some pharmacies may also be closed due to the extended Labor Day holiday weekend.
Before Thursday’s vote, many panel members expressed discomfort at the lack of data in humans to evaluate the new boosters, saying the lack of testing on humans could lead to people not getting the shots. Some panelists suggested that the original vaccines remain on the market. Others said the US should distribute similar vaccines, from Pfizer and Moderna, that target the original strain of omicron, called BA.1, that have been tested on humans.
Despite the concerns and the need for more information, the committee voted overwhelmingly in favor of recommending the doses.
“We expect a tough winter season to come, with both flu and Covid-19 and I think our job is to do our best to protect public health,” said committee chair Dr. Grace Lee, professor of pediatrics at Stanford University. She voted yes.
Commissioner Dr. Pablo Sanchez, a pediatrician at Nationwide Children’s Hospital in Ohio, was the only one to disagree. He said he advised against the shots because there was no human data.
“That’s very important to me,” he told his colleagues after the vote. “It’s a new vaccine, it’s a new platform. There is already a lot of hesitation about vaccines. We need the human data.”
The process of adapting the Covid vaccine to target a different variant is similar to how the flu vaccine is updated every year. Those annual recordings are being rolled out without human trial data.
The Biden administration is urging all eligible people in the US to get the new boosters as part of its fall booster campaign. In the future, the custom shots will be the only boosters available for teens and adults.
Both modified boosters target the BA.4 and BA.5 omicron subvariants at once, in addition to the original coronavirus strain.
Officials say the new boosters could hold the key to slowing a decline wave of the BA.5 omicron subvariant, currently the dominant strain in the US. Still, the uptake of the existing boosters remains low, with less than half of people eligible to receive their first booster dose, Show CDC data.
A model presented by the CDC at Thursday’s meeting predicted that — assuming no new variant comes — administering the boosters in September could prevent 137,000 more hospitalizations and 9,700 more deaths compared to administering them in November.
In addition to preventing serious illness and death, boosters may also protect against coronavirus infections, Ruth Link-Gelles, an epidemiologist at the CDC, said in a presentation to the committee.
Vaccine efficacy against infection appears to decline more slowly after a third dose of a vaccine compared to two doses alone, according to the data. The pattern was seen across multiple age groups, Link-Gelles said.
Representatives from Pfizer and Moderna presented data showing that similar vaccines, targeting the original omicron variant, called BA.1, were safe in humans and produced a stronger immune response to BA.1 than the existing vaccines. The vaccines also produced immune responses to the original coronavirus strain that were similar to the existing vaccines.
The companies also presented data to the committee showing that the vaccines targeting BA.5 elicited a strong immune response in mice.
The risk of a rare heart infection called myocarditis caused by the new booster is unknown at this time, Dr. Sara Oliver, an epidemic intelligence agency for the CDC, to the committee.
Both Pfizer’s and Moderna’s first versions of the Covid vaccines have been linked to a small but increased risk of the heart disease, especially in young men.
But it’s unlikely, Oliver said, that including the BA.4 and BA.5 components in the new booster would increase the rate of the condition.
Still, some committee members suggested widening the gap between doses beyond 2 months to reduce the risk of the condition.
The CDC also offered clearer guidelines about when people who have recently had Covid can get a booster. At the very least, people should wait until they have recovered from the disease and ended isolation. But people may also consider delaying a booster for 3 months after infection, depending on risk factors.