Alliance for Pandemic Preparedness

April 16, 2021

SARS-CoV-2 Seropositivity and Subsequent Infection Risk in Healthy Young Adults: A Prospective Cohort Study

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  • US Marine recruits who were seropositive for SARS-CoV-2 antibodies at baseline were 82% less likely than seronegative individuals to have a PCR-confirmed SARS-CoV-2 infection during a 6-week long cohort study. The study population consisted of predominantly male US Marine recruits aged 18-20 years (n=3,076). At baseline, all participants were PCR-negative. During the study period, 19 of 189 seropositive participants (10%) had at least one positive PCR test compared to 1,079 of 2,247 seronegative participants (48%) (1.1 vs 6.2 cases per person-year). Among seropositive participants, infection was less likely among those with higher baseline IgG titers. Higher baseline neutralizing titers were more frequently detected in seropositive participants who remained uninfected than those who were infected (83% vs 32%).

Letizia et al. (Apr 15, 2021). SARS-CoV-2 Seropositivity and Subsequent Infection Risk in Healthy Young Adults: A Prospective Cohort Study. The Lancet Respiratory Medicine. https://doi.org/10.1016/S2213-2600(21)00158-2