What we’re learning from the rare cases of COVID-19 in vaccinated people
Among the more than 75 million people fully vaccinated against COVID-19 in the United States by the second week of April, there were only 5,814 reports of coronavirus infections — a staggeringly low number that shows just how effective the shots are.
Because the vaccines aren’t 100 percent effective, some breakthrough infections were inevitable and expected. Still, the Centers for Disease Control and Prevention is watching them closely. Studying those cases willhelp experts make sure the vaccines are working as expected and understand any factors that make it more likely that a vaccinated person would get sick.