The new shots from Pfizer and Moderna use the messenger ribonucleic acid (mRNA) platform and target the XFG strain, a subvariant of the JN.1 variant.

Regulators also cleared a COVID-19 vaccine shot from Sanofi that targets the XFG strain and does not use mRNA technology.

The approval is for people aged 65 and older, as well as people aged 12 to 64 who have one or more underlying conditions such as obesity that officials say puts them at higher risk of severe COVID-19.

Regulators have been approving updated COVID-19 vaccines for several years, in a bid to better match circulating strains. The previous versions of the vaccines were estimated to provide 58 percent protection against hospitalization, according to the Centers for Disease Control and Prevention.

The FDA did not announce the approvals in a press release, as it has done in the past.

The FDA and its parent agency, the Department of Health and Human Services, did not respond to requests for comment by publication time.

Health Secretary Robert F. Kennedy Jr. has been critical of mRNA vaccines against respiratory diseases, saying they don't work well.

Manufacturers are going to run single-arm studies evaluating the shots in humans, according to FDA documents. The companies were going to be made to run placebo-controlled trials, but officials released them from that requirement "because of operational and feasibility challenges," the documents said.

FDA officials in 2025 said that new placebo-controlled trials were imperative to determine how well the COVID-19 vaccines actually performed, given it has been years since such trials were conducted. Pfizer and Moderna committed to running placebo-controlled trials, as did Novavax, which has since licensed its COVID-19 vaccine to Sanofi.

The basis of the approvals was largely not detailed in the documents. During an advisory meeting in the spring, the vaccine manufacturers presented data from animal testing, but no data from human testing. The FDA's vaccine advisory committee then recommended the next round of COVID-19 vaccines target XFG.

Uptake of COVID-19 vaccines has plummeted in recent years. Just 17.5 percent of adults and 10 percent of children received a shot in late 2025 or early 2026, according to the CDC.

COVID-19 infections are growing or likely growing in 47 states, the CDC said in modeling estimates released this month.