Fast Five Quiz: COVID-19 Prevention

Michael Stuart Bronze, MD


December 16, 2022

In a database study of 5,693,208 million people, individuals with reinfection showed increased risks for all-cause mortality, hospitalization, and several prespecified outcomes compared with those with first infection. These risks were seen in those who were unvaccinated, had one shot, or two or more shots prior to the second infection. While such risks were most evident in the acute phase of reinfection, they were also seen in the post-acute phase. Risk and burden increased with the number of infections.

The rate of reinfection has proven to be higher in the Omicron era compared with previous strains. In a population-based cohort study, a significant proportion of individuals experienced SARS-CoV-2 reinfection during the first 74 days of the Omicron wave in Iceland, with two or more doses of vaccine associated with a slightly higher probability of reinfection compared with one or less than one dose. However, there is evidence that previous Omicron infection in triple-vaccinated individuals provides strong protection against BA.5 and BA.2 infections.

In addition, a recent study concluded that hybrid immunity resulting from previous infection and recent booster vaccination conferred the strongest protection against infection with Omicron.

Learn more about COVID-19.

Editor's Recommendations


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.