(KTXL) — Adults and certain immunocompromised individuals can now go to Rite Aid to get a second COVID-19 booster shot.

The drugstore chain said starting Wednesday, those who are eligible can go to any Rite Aid location in California to receive another dose of either the Pfizer or Moderna COVID-19 vaccine. Walk-ins are welcome or appointments can be made online.

Those 50 and older, as well as people 12 and older with weakened immune systems, were given the OK to get a second booster after the Food and Drug Administration and the Centers for Disease Control and Prevention both gave their stamps of approval Tuesday.

To receive another booster, eligible individuals have to wait at least four months after their first booster shot.

Pfizer had asked the FDA to clear another shot for people 65 and older, while Moderna requested another dose for all adults “to provide flexibility” for the government to decide who really needs one.

There’s limited evidence to tell how much benefit another booster could offer right now. The FDA made the decision without input from its independent panel of experts that has wrestled with how much data is required to expand shots.

The move comes at a time of great uncertainty. COVID-19 cases have dropped to low levels after the winter surge of the super-contagious omicron variant. Two vaccine doses plus a booster still provide strong protection against severe disease and death, CDC data show.

“During the recent Omicron surge, those who were boosted were 21-times less likely to die from COVID-19 compared to those who were unvaccinated, and 7-times less likely to be hospitalized,” the CDC said in its recommendation for additional boosters.

But an omicron sibling is causing a worrisome jump in infections in Europe — and spreading in the U.S. — even as vaccination has stalled. About two-thirds of Americans are fully vaccinated, and half of those eligible for a first booster haven’t gotten one.

The Associated Press contributed to this report.