Anti-spike antibody response to natural SARS-CoV-2 infection in the general population

Wei, J.; Matthews, P. C.; Stoesser, N.; Maddox, T.; Lorenzi, L.; Studley, R.; Bell, J. I.; Newton, J. N.; Farrar, J.; Diamond, I.; Rourke, E.; Howarth, A.; Marsden, B. D.; Hoosdally, S.; Jones, E. Y.; Stuart, D. I.; Crook, D. W.; Peto, T. E. A.; Pouwels, K. B.; Walker, A. S.; Eyre, D. W.

We estimated the duration and determinants of antibody response after SARS-CoV-2 infection in the general population using representative data from 7,256 United Kingdom COVID-19 infection survey participants who had positive swab SARS-CoV-2 PCR tests from 26-April-2020 to 14-June-2021. A latent class model classified 24% of participants as 'non-responders' not developing anti-spike antibodies. These seronegative non-responders were older, had higher SARS-CoV-2 cycle threshold values during infection (i.e. lower viral burden), and less frequently reported any symptoms. Among those who seroconverted, using Bayesian linear mixed models, the estimated anti-spike IgG peak level was 7.3-fold higher than the level previously associated with 50% protection against reinfection, with higher peak levels in older participants and those of non-white ethnicity. The estimated anti-spike IgG half-life was 184 days, being longer in females and those of white ethnicity. We estimated antibody levels associated with protection against reinfection likely last 1.5-2 years on average, with levels associated with protection from severe infection present for several years. These estimates could inform planning for vaccination booster strategies.