The Food and Drug Administration on Thursday cleared new versions of Pfizer’s and Moderna’s COVID-19 vaccines that are designed to better match the coronavirus strains currently circulating in the U.S.

Both of Pfizer’s and Moderna’s reformulated shots target the KP.2 virus strain, which was dominant in the spring and belongs to the broader JN.1 lineage. Under the FDA’s new clearance, most people 12 years of age and older are eligible to receive a single dose of either of the updated vaccines.

The regulator also issued an emergency use authorization for the new shots to be used in children 6 months through 11 years of age, with dosing dependent on age and the number of prior doses received.

So far, the FDA has been following a model akin to its practice for influenza vaccines, convening experts in the spring and summer to discuss the best strain for manufacturers to design their shots against.

Initially, the agency favored redesigning COVID vaccines to match the JN.1 variant broadly. It later specified that developers should focus on KP.2 specifically, if possible. The KP.2-targeting shots are expected to produce immune responses that also provide protective benefits against other strains within the JN.1 lineage.

The FDA’s approval comes just ahead of the fall and winter seasons, when COVID cases and hospitalizations are expected to climb.

“Given waning immunity of the population from previous exposure to the virus and from prior vaccination, we strongly encourage those who are eligible to consider receiving an updated COVID-19 vaccine to provide better protection against currently circulating variants,” said Peter Marks, head of the FDA office that reviews vaccines, in a statement.

Pfizer and partner BioNTech said shipping of their reformulated vaccine will begin immediately and that doses will be available “in the coming days.” Moderna said its shot will be available in pharmacies and clinics in the same time frame.

The companies are using similar processes to manufacture their updated vaccines as they did with prior versions. Their approvals were based on the FDA’s review of manufacturing data and nonclinical study results designed to show the shots are effective and safe. Side effects, such as injection site pain and headaches, are anticipated to be like previous boosters.

“These updated vaccines meet the agency’s rigorous, scientific standards for safety, effectiveness, and manufacturing quality,” Marks said.

Novavax has also developed an updated version of its COVID vaccine which, unlike Pfizer’s and Moderna’s mRNA shots, is protein-based. The company has also submitted an application for authorization to the agency.

In June, the Centers for Disease Control and Prevention recommended that everyone aged 6 months and older receive an updated COVID vaccine when they are available.

While COVID vaccine uptake could rise this fall, both Pfizer and Moderna have in recent quarters reported steadily declining revenues from their vaccines. As a results, investors have turned their attention toward combination shots the companies are developing, as well as vaccines for respiratory syncytial virus.

By: DocMemory
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