WASHINGTON — The Food and Drug Administration on Wednesday authorized booster shots for tens of millions of recipients of Moderna’s two-dose coronavirus vaccine and the roughly 15 million who got Johnson & Johnson’s single-dose shot, significantly expanding the nation’s campaign to bolster protection for vulnerable people.
The agency also updated its authorizations for all three vaccines — Moderna, Johnson & Johnson and Pfizer-BioNTech — to allow medical providers to boost people with a different Covid-19 vaccine than the one