Covid Immunity Lasts at Least a Year After Infection Plus Shots

People who have been both previously infected and vaccinated against Covid-19 get long-lasting protection against severe disease and hospitalization, a large international study found.

The combination prevented more than 97% of severe disease or hospitalization for up to 12 months after infection or initial immunization, whichever was most recent, according to a report from the World Health Organization. Boosters conferred an additional 6 months of protection. Meanwhile, infection alone was just under 75% protective over a year.

The report was based on a review of more than two dozen studies from January 2020 to June 2022 on protection ...