Previously, states reported all cases of breakthrough infection, regardless of severity, to the CDC. States will continue to report all positive cases of Covid-19 to the CDC — including any mild or asymptomatic breakthrough cases — but the agency will not differentiate between mild or symptom-free cases in vaccinated versus unvaccinated people. It is unclear if states will continue to collect mild or asymptomatic breakthrough case data. The CDC spokesperson told CNN that the change in breakthrough case reporting would not affect the understanding of vaccine efficacy. “CDC is still doing studies on mild breakthrough infections, so people should not...
