Does a previous infection with COVID-19 protect against a new infection?

A previous infection with COVID-19 does provide some protection against a new infection, but this protection is not absolute and may decrease over time.

After infection with SARS-CoV-2 (the virus that causes COVID-19), the body develops an immune response, including the production of antibodies and T cells that specifically target the virus. This provides some protection against future infections.

Studies have shown that immunity after natural infection can last from several months to a year or more, but the strength and duration of this protection can vary. In some people, the number of antibodies and the effectiveness of the immune response decreases over time, increasing the risk of reinfection.

Reinfections with COVID-19 are possible, and several cases have been reported worldwide. Usually, reinfections are milder than the first infection, but there have been cases where the second infection was more severe. This can depend on several factors, such as the variants of the virus and the overall health of the person.

New variants of the virus, such as the Delta and Omicron variants, can partially escape the immunity built up by a previous infection. This means that someone who has previously had COVID-19 can still become infected again, especially if the new variant is significantly different from the variant that caused the first infection.

Source: https://pubmed.ncbi.nlm.nih.gov/33705690/

Author: Prof. Dr. Dirk Devroey - Latest update: 2022-12-01 - Copyright: Clinifacts 2025