When the Delta variant dominated, vaccination and prior infection protected against Covid-19, but vaccination was safest, study finds

 https://edition.cnn.com/2022/01/19/health/covid-vaccine-infection-protection-cdc-study/index.html

"Together, the totality of the evidence suggests really that both vaccination and having survived Covid each provide protection against subsequent reinfection, infection and hospitalization," said Dr. Eli Rosenberg, New York state deputy director for science. "Having Covid the first time carries with it significant risks, and becoming vaccinated and staying up-to-date with boosters really is the only safe choice for preventing COVID infection and severe disease."

"If a person who's had natural Covid then gets vaccinated, they have levels of antibody that are much, much higher than after the natural infection itself. And what we know about higher levels of antibody is: one, you usually get a longer duration of protection, and number two, the variety of antibodies that your immune system produces is more diverse. The notion is that you will be better protected against a diversity of variants," said Schaffner, who is a vaccine adviser to the CDC, but was not involved in the study.