Medical research: SARS-CoV-2 immune response related to disease severity

The immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wanes in the three months following infection and is dependent on the severity of the disease, suggests a paper in Nature Microbiology. The study, which provides insights into the body’s response to the virus, has notable implications for vaccine design and disease management.

Although people infected with SARS-CoV-2 generate an immune response to the virus, the duration of the response is uncertain and it has been unclear how long individuals will be protected for. Katie Doores and colleagues studied the antibody response of 59 patients and 37 healthcare workers at Guy’s and St Thomas’ NHS Foundation Trust in London for three months following the onset of their symptoms.

Typical of an acute viral infection, the antibody response peaked at around one month after the onset of symptoms, before starting to decline. People with severe disease generated the strongest antibody response, and although this response diminished, neutralizing antibodies were still detectable more than 60 days after symptoms began. People with milder disease also generated an immune response, but it was smaller and declined towards baseline levels. Some healthcare workers, for example, had no detectable immune response within the same follow-up period.

The study suggests that people who experience more severe COVID-19 disease may be protected for longer periods than people who experience milder symptoms, and that the kinetics of the response are similar to other endemic seasonal coronaviruses. The authors note that vaccines will need to generate a robust and long-lasting immune response akin to that generated in severely ill patients, and that boosters may be required to provide long-lasting protection.