The shot, named mFlusiva, is intended for adults age 50 or older.
Moderna's COVID-19 vaccine, Spikevax, had more than $3 billion in sales last year.
The FDA said the new booster option is for adults who can't get one of the updated omicron-targeting Pfizer or Moderna boosters.
Officials hope to expand protection against an expected winter surge.
U.S. regulators have authorized updated COVID-19 boosters, the first to directly target today's most common omicron strain.
Moderna and Pfizer’s two-shot vaccines both use mRNA technology to help patients fight the coronavirus.
About 261 million Americans have received at least one COVID-19 shot, but only 108 million have received a booster.
Western states safety review finds Pfizer, Moderna vaccines safe for children as young as six months
The Workgroup provided its confirmation to the Governors of California, Nevada, Oregon, and Washington.
A final signoff from the Centers for Disease Control and Prevention is expected this weekend.
If all the regulatory steps are cleared, shots should be available next week.