Previous infection provides protection against COVID-19 for several months

People previously infected with SARS-CoV-2 are substantially protected against COVID-19 for several months, even in the absence of vaccination, a study found. Beyond that, however, their natural immunity wanes but may be boosted with vaccination, researchers reported in findings from a study conducted among employees of the Cleveland Clinic between Dec. 16, 2020, and Dec. 27, 2021. The study period included the emergence of the delta and omicron variants of SARS-CoV-2. The researchers found that natural immunity that is several months old does not protect against the omicron variant. “The arrival of the omicron variant greatly changed the risk of COVID-19 for all individuals regardless of whether they were previously infected or not, and regardless of whether they were previously vaccinated or not,” Nabin K. Shrestha, MD, MPH, a staff physician in the Cleveland Clinic department of infectious diseases, told Healio. “Protection against COVID-19 from prior infection or vaccination may be of shorter...