The CDC’s Advisory Committee on Immunization Practices voted 13 to 1 earlier in the day to recommend updated mRNA boosters for Americans this fall.
Walensky’s decision means the shots could be available by Friday, according to pharmaceutical makers, which began shipping the new doses after the US Food and Drug Administration cleared them on Wednesday.
“The updated COVID-19 boosters are formulated to better protect against the newest circulating COVID-19 variant,” Walensky said in a statement. “They can help restore protection that has waned since previous vaccination and have been designed to provide broader protection against newer variants. This recommendation follows a full scientific assessment and extensive scientific discussion. If you’re eligible, there’s no bad time to get your COVID-19 reminder and I strongly encourage you to get it.”
The updated boosters have instructions that tell our cells to make antibodies against two strains of the virus that causes Covid-19: the original strain and the BA.4 and BA.5 Omicron subvariants, which share the same peak.
The updated vaccine from Pfizer/BioNTech is a 30 microgram dose authorized for people 12 years and older. Moderna’s updated vaccine is an authorized 50-microgram dose for people 18 years of age and older.
The CDC said in the statement that it “also plans to recommend updated COVID-19 boosters for other pediatric groups” in the coming weeks.
People are eligible for updated boosters as long as they have completed all primary doses of their vaccine series. The committee recommended that new boosters be given at least two months after the last dose of any Covid-19 vaccine and up to three months after an infection.
The new formulations do not replace the injections of the primary series.
The boosters were approved based on studies in mice bred to have human ACE-2 receptors – the gates the coronavirus uses to enter our cells – but clinical trial data showing how well they can work in humans won’t be available for another month or two.
This is similar to how annual flu shots are researched and approved, but this is the first time for Covid-19 vaccines.
In approving vaccines, regulators have also looked at the data behind different two-strain boosters. These carry instructions for combating the original strain of the Omicron variant, BA.1, as well as the original virus. These reminders have been studied in about 1,400 people. They have been licensed for use in the UK and Canada, but will not be available in the US.
Several committee members said Thursday they weren’t comfortable recommending a vaccine without human data to support it.
“We’re extrapolating the data that was seen with the bivalent BA.1, and hopefully we’ll have similar data for BA.4 and BA.5,” said Dr. Pablo Sanchez, a pediatrician at Ohio State University. . and a committee member.
“So I’m just concerned about that extrapolation. And because at the end of the day, I really don’t want to set a precedent by recommending a vaccine that we don’t have clinical data for,” said Sanchez, who voted against the recommendation.
This prompted a swift rebuttal from government experts working with the committee.
“I would just like to remind the committee that every year we use flu vaccines based on new strains without any clinical studies being done,” said Dr. Melinda Wharton, associate director of vaccine policy at the National Center for Immunization. and Respiratory from the CDC. Diseases.
Dr. Doran Fink, Deputy Director of the FDA’s Division of Vaccines and Related Products Applications, said, “I appreciate the level of discomfort I hear from committee members who are being asked to take that leap with Covid vaccines that they weren’t asked to do before with Covid vaccines.
“The FDA felt very comfortable with the approach of extrapolating safety and effectiveness or rather known and potential benefits,” Fink said. “We recognize that we have taken a different path than regulatory authorities in Europe and Canada.”
Fink said the United States chose this path based on feedback from its independent advisory group and projections of the viruses that may be circulating in that country over the fall and winter.
On Thursday, the committee saw new modeling data suggesting there were substantial risks waiting to deploy new boosters.
Boosters given to American adults in September could avert 137,000 more hospitalizations and 9,700 more deaths than if boosters were given through November, according to CDC forecasts.
New analyzes on the cost-effectiveness of boosters suggest that the United States could save at least $63 billion in medical costs between August and March 31 if as many people receive these boosters as people get the flu shot over the course of of the 2021-22 season.
In studies that examined the BA.1-targeting shot with the original, the boosters broadened immunity against many variants, and they were found to be better than the older single-strain boosters because they produced higher levels of antibodies higher.
Moderna presented tantalizing data suggesting that the two-strain shots it developed against the beta variant could extend the length of protection people get from their vaccines, which currently declines significantly after about four months. He said a study of these findings was being prepared for publication.
In mice bred to have human ACE-2 receptors, the two-strain vaccines against BA.4 and BA.5 protected better against lung infections, compared to the original vaccine.
About two-thirds of the total US population are vaccinated against Covid-19 with a first round, according to CDC data. But less than half of those with their initial set – and less than a third of the total population – also received a booster.
CNN’s Naomi Thomas and Deidre McPhillips contributed to this report.