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Pfizer asks FDA to authorize updated booster shot

The updated shot targeted the BA.5 subvariant of omicron, which is currently the dominant strain in the U.S.
/ Source: NBC News

Pfizer-BioNTech asked the Food and Drug Administration to authorize an updated version of its COVID booster designed to target the BA.5 omicron subvariant, the drugmaker announced in a release Monday.

Pfizer’s release was sparse on new details about the efficacy of the booster, but the company said studies in animals found that the vaccine generated an immune response against multiple versions of omicron, including BA.4 and BA.5. It is planning to start clinical trials in people this month, the statement said.

The request, covering people ages 12 and up, will now be considered by the FDA, which will review the data and is expected to grant emergency use authorization for the age group sometime in September.

If authorized, the company said it is prepared to immediately begin distribution of the shots.

The updated shots are expected to be rolled out as part of a fall booster campaign ahead of a potential winter surge in COVID cases, White House COVID coordinator Dr. Ashish Jha said last week.

Pfizer’s so-called bivalent booster targets the omicron subvariants BA.4 and BA.5, as well as the original strain of the virus, in a single shot. BA.5 accounts for nearly 90% of new COVID cases in the United States, according to the Centers for Disease Control and Prevention.

In June, the company released clinical trial data on a different version of a bivalent shot, one that targeted the original omicron variant. That booster was shown to be safe and produced an immune response.

The FDA is allowing Pfizer to submit less data on the shot than it has for previous COVID vaccines. The agency released guidance last year that said modified vaccines that target new, emerging strains of the coronavirus may be authorized without the need for lengthy clinical trials.

Dr. Jesse Goodman of Georgetown University, a former FDA vaccine chief, said it “makes sense” to update the vaccines to target new variants circulating.

How effective Pfizer’s new bivalent vaccine is compared to the existing vaccines remains unclear. Goodman said he specifically wants to see how well the vaccines perform against infections.

It is “likely” the immune responses in people will be similar to those seen in the animal studies, he said, but “it is not known until human data are available.”

Moderna is also preparing to ask the FDA to authorize its bivalent vaccine that targets BA.4 and BA.5, as well as the original strain.

Monday’s announcement comes as the existing booster shots, from Pfizer and Moderna, have been a poor match for omicron and its growing family of subvariants. The shots, which target the original coronavirus strain identified in Wuhan, China in late 2019, still offer strong protection against severe illness.

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