https://www.siliconvalley.com/2021/10/15/covid-not-everyone-will-need-a-booster-experts-say/

(CNN) — Advisers from the US Food and Drug Administration voted unanimously to recommend emergency authorization of a booster dose of Moderna’s Covid-19 vaccine, and a day later did so again for a booster of Johnson & Johnson’s vaccine.

The group voted Friday to authorize a booster shot of Johnson & Johnson’s vaccine for Americans 18 and older at least two months after they get their first shots. Johnson & Johnson said studies showed boosting at two or six months can bring effectiveness up to 94%.