The new Covid-19 booster shot in the US: what you need to know

Nurses prepare doses of an earlier Covid-19 vaccine at a pop-up vaccination clinic at the St. Bernadette Catholic church in Los Angeles, California, last year. Photograph: Étienne Laurent/EPA

A retooled single-dose Covid “booster” shot is expected to hit pharmacy shelves just as cold and flu season is ramping up. This week, the Food and Drug Administration (FDA) authorized new shots for emergency use, and a panel of experts at the Centers for Disease Control and Prevention (CDC) recommended nearly everyone in the US get one.

But just how soon should people in the US head to their local pharmacies for the new vaccine? And, after so many people have already been vaccinated or sickened by Covid, how urgent is it to get another dose? Below, we fill in details of the agencies’ latest recommendations.