(CNN) When the Delta variant was dominant in the United States, both vaccination and prior infection helped protect against Covid-19, but vaccination was the safest way to be protected, according to a study published Wednesday by the US Centers for Disease Control and Prevention. The CDC says it will publish additional data on Covid-19 vaccines, boosters and the Omicron variant later this week. Researchers analyzed the risk of Covid-19 infection and hospitalization among four groups of individuals: vaccinated with and without prior infection and unvaccinated with and without prior infection. Hospitalization data was available from California only. Overall, Covid-19 case and hospitalization rates were highest among unvaccinated people who did not have a previous diagnosis.

Source: CNN January 20, 2022 15:06 UTC