SARS-CoV-2 antibodies may protect against reinfection for at least 6 months

According to a recent prospective longitudinal cohort study in healthcare workers, those with SARS-CoV-2 antibodies from a previous infection had a reduced risk of reinfection in the following 6 months.

The study followed 12,541 healthcare workers from Oxford University Hospitals in the United Kingdom to compare the incidence of SARS-CoV-2 infection in seropositive and seronegative patients. Their baseline antibody statuses to the SARS-CoV-2 spike and nucleocapsid were determined and followed for up to 31 weeks.

11,264 participants were seronegative and 1,265 were seropositive including 88 who became seropositive during follow-up. In those who tested negative for antibodies against the SARS-CoV-2 spike, 223 tested positive for the virus at baseline. No symptomatic infections and only 2 cases of asymptomatic reinfection were detected in seropositive healthcare workers.

Overall, 218 participants tested positive in the seronegative group versus 1 who was seropositive for both viral proteins, and 2 with mixed antibody results, showing a significantly lower risk of reinfection in the seropositive group.

Why it matters: Although further characterisation is needed, the immune response induced by previous SARS-CoV-2 infection via antibodies may offer protection against reinfection for a certain time period. More research is required to assess the degree and exact duration of protection against reinfection, disease, and transmission.

Source: New England Journal of Medicine