CDC Recommends Updated COVID-19 Boosters

A vial of Pfizer's COVID-19 vaccine in a file image. (Asanka Ratnayake/Getty Images)

The director of the U.S. Centers for Disease Control and Prevention (CDC) on Sept. 1 recommended updated COVID-19 boosters for all Americans aged 12 years and older.

Dr. Rochelle Walensky, the director, adopted advice from the Advisory Committee on Immunization Practices, which advises the CDC on vaccine guidance.

“The updated COVID-19 boosters are formulated to better protect against the most recently circulating COVID-19 variant. They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants," Walensky said in a statement.

"This recommendation followed a comprehensive scientific evaluation and robust scientific discussion. If you are eligible, there is no bad time to get your COVID-19 booster and I strongly encourage you to receive it," she added.

The recommendation is for Pfizer's booster for Americans aged 12 years and up and for Moderna's booster for American adults.

People are advised to get the updated boosters as soon as two months after their most recent shot, down from five months.

Many institutions, including schools, cite the CDC's recommendations when imposing vaccine mandates.

The old boosters will no longer be available. The primary series of the vaccines will remain the same, or based on the original Wuhan COVID-19 strain. The updated boosters contain components of the spike protein from the BA.4 and BA.5 Omicron subvariants. BA.5 is the dominant strain in the United States at present.

U.S. drug regulators authorized the new boosters this week, based on clinical data from different products and preclinical data from mice.

Members of the vaccine advisory panel noted the dearth of human data for the boosters.

"I really do struggle with a vaccine that has no clinical data that has been reported for humans," Dr. Oliver Brooks, one of the members, said during the meeting.

Most of the data presented by Moderna and Pfizer dealt with a human trial that tested a different formulation, a bivalent with components of the original virus strain and the BA.1 strain.

The Moderna trial enrolled those aged 18 years and older; Pfizer only delivered data for those aged 55 years and up.

"And yet we're going to make a recommendation for 12 and over," Dr. Pablo Sanchez, another member, said.

Flu Vaccines

Sanchez said he was concerned about extrapolating the data for a different product and said he did not want to "establish a precedent of recommending a vaccine that we don't have clinical data on."

Dr. Melinda Wharton, the panel's executive secretary and a CDC official, urged members to think about how influenza vaccines are updated each year without clinical data, and other members said they appreciated the comparison.

"Almost the only reason I voted yes [is] because I'm thinking about how we do flu vaccines on a yearly basis," Brooks said, calling it a "difficult vote."

"We should be treating this like the flu where if we have evidence that the pattern seems to flow smoothly, and that we can use new strain variants every year, I think that's the way we're going to be going over the next several years," Dr. Jamie Loehr, another member, said.

Others said the preclinical data, based on reactions recorded in mice, and the data on the BA.1/Wuhan bivalent was adequate, along with the data from the old vaccine, which only contains the original virus.

"I wanted to say that as a clinician, in making a decision for individuals, I would be on Dr. Sanchez's side and I make this decision for the best of the most people, considering and hoping that the advantages will outweigh any risks that we not yet anticipate," Dr. Sarah Long, also a member, said after the vote.