WASHINGTON — The Food and Drug Administration has moved to expand its emergency authorization of Pfizer’s and Moderna’s COVID-19 vaccine booster shots to all adults, the companies announced Friday, as health officials are clamoring to head off a potential new surge of cases this winter.

The Centers for Disease Control and Prevention must also weigh in with its recommendations before third doses can officially be greenlighted under federal supply agreements governing use of the shots. But a growing number of state and local health departments are not waiting and have already announced expanded eligibility on their own.

A panel of the CDC’s outside vaccine advisers, the Advisory Committee on Immunization Practices, are scheduled to meet Friday afternoon to vote on updated recommendations.