CDC recommends updated Covid-19 boosters

The Centers for Disease Control and Prevention recommended use of two new Covid-19 vaccine boosters on Thursday, opening the door to administration of the first updated vaccines since the start of the pandemic vaccination effort in December of 2020.

CDC Director Rochelle Walensky issued the recommendations for the vaccines — made by Moderna and by Pfizer and its partner, BioNTech — after an expert panel that advises the CDC on vaccine policy voted to urge her to do so.

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

“If you are eligible, there is no bad time to get your COVID-19 booster and I strongly encourage you to receive it.”

The Advisory Committee on Immunization Practices voted 13 to 1 to recommend both shots. The Pfizer vaccine is authorized for use in people 12 and older, the Moderna in people 18 and older.

The sole no vote was from Pablo Sánchez, a professor of pediatrics at the Ohio State University and Nationwide Children’s Hospital. Sánchez said he believes the vaccine will be effective and safe, but he felt the lack of human safety and efficacy data for the boosters was a sticking point.

“I voted no because I really feel that we need the human data,” Sánchez told his colleagues after the vote. “There’s a lot of vaccine hesitancy already. …I just feel this was a bit premature.”

The vaccine was authorized based on studies in mice and on data drawn from a bivalent booster that contained a slightly different formulation. Sánchez was not the only person who expressed concern about the lack of human data on the specific boosters. Helen “Keipp” Talbot, associate professor of medicine at Vanderbilt University, struggled to cast a vote, asking ACIP chair Grace Lee for more time to make her decision. But in the end, she and all other members of the committee voted to recommend the vaccines.

Matthew Daley, who chairs the ACIP’s Covid vaccine work group, said he understood the concerns, but felt that waiting until November — the estimate of how long it will take to generate the data the committee was asking for — could lead to significantly higher rates of Covid illness, hospitalizations, and deaths this fall.

Both the Food and Drug Administration and the CDC stressed that flu vaccines are updated annually in the same way.

The FDA, which issued emergency use authorizations for the updated boosters on Wednesday, said it wants more data from the manufacturers before authorizing these shots for younger children. The manufacturers said Thursday they are working to generate these data.

Earlier this week Claire Hannan, executive director of the Association of Immunization Managers, told STAT the updated boosters may be available in some locations as early as Saturday. In other places, they will arrive early next week.

Pfizer said in a statement that it shipped more than 100,000 doses to 62 locations across the country on Wednesday; those doses were scheduled to arrive Thursday. An additional approximately 3 million doses would be situated at more than 3,300 sites by Tuesday, the company said.

The new boosters represent the first time Covid vaccines have been reformulated. Until now all vaccines have targeted only the original strain of the SARS-CoV-2 virus that emerged in China in late 2019.

The updated vaccine is designed to teach the immune system to recognize a broader array of SARS-2 strains by including a second target, the Omicron subvariants BA.4 and BA.5. (The spike protein on viruses from those two subvariants is identical.) BA.5 is currently the dominant virus circulating in the United States.

The new shots can only be used as a booster for people who have had a primary series of vaccines. It is not authorized for use as a primary series.

With the authorization of these boosters, the FDA suspended the authorizations for the previous boosters produced by Pfizer and Moderna. Those monovalent (one strain) boosters can no longer be given in this country, except in children who are too young to receive one of the bivalent boosters.

ACIP members had other concerns that were discussed at some length during the full-day meeting. A number were uneasy about the fact that the recommendations stated that people could get one of these updated boosters two months after having received an earlier Covid vaccine, with the concerns hinging on the fact that the interval may be too short to get maximum benefit from the new shot, and might raise the risk some recipients will develop myocarditis — inflammation of heart muscle that is a rare side effect of the messenger RNA vaccines.

Lee mentioned that she will advise her patients to wait at least three months before getting one of the new boosters.

But CDC staff who advise the committee noted most people who have been vaccinated against Covid will be many more months from having received their most recent dose. And Sara Oliver, a CDC epidemiologist, noted that the two-month interval is a one-time thing, as the Covid vaccination program attempts to transition to what may end up being annual Covid boosters. “Hopefully the future interval is considerably longer,” she said.

Daniel McQuillen, president of the Infectious Diseases Society of America, said his group applauds ACIP’s recommendations.

“Covid-19 is not over. Nearly 400 people die from Covid every day, and almost 5,000 people are currently hospitalized with Covid,” he said in a statement. “Evidence shows that these bivalent vaccines — created specifically for the highly transmissible Omicron variant — provide needed broader and more durable protection.”