The WHO calls for a pause in the world's booster plans, while San Francisco gives Johnson & Johnson recipients the green light for an mRNA dose. Here's what's going on with boosters.
With breakthrough infections in fully vaccinated people, the debate is over whether booster shots are needed to protect against the highly contagious strain.
A CDC report provides evidence that the delta variant is transmissible in vaccinated people who get infected. But that's not a reason to question vaccines, experts say.
