Abstract
Background: Serological assays detecting anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies are being widely deployed in studies and clinical practice. However, the duration and effectiveness of the protection conferred by the immune response remains to be assessed in population-based samples. To estimate the incidence of newly acquired SARS-CoV-2 infections in seropositive individuals as compared to seronegative controls, we conducted a retrospective longitudinal matched study.
Methods: A seroprevalence survey including a representative sample of the population was conducted in Geneva, Switzerland, between April and June 2020, immediately after the first pandemic wave. Seropositive participants were matched one-to-two to seronegative controls, using a propensity-score including age, gender, immunodeficiency, body mass index (BMI), smoking status, and education level. Each individual was linked to a state-registry of SARS-CoV-2 infections. Our primary outcome was confirmed infections occurring from serological status assessment to the end of the second pandemic wave (January 2021).
Results: Among 8344 serosurvey participants, 498 seropositive individuals were selected and matched with 996 seronegative controls. After a mean follow-up of 35.6 (standard deviation [SD] 3.2) weeks, 7 out of 498 (1.4%) seropositive subjects had a positive SARS-CoV-2 test, of whom 5 (1.0%) were classified as reinfections. In contrast, the infection rate was higher in seronegative individuals (15.5%, 154/996) during a similar follow-up period (mean 34.7 [SD 3.2] weeks), corresponding to a 94% (95% confidence interval [CI]: 86%- 98%, P < .001) reduction in the hazard of having a positive SARS-CoV-2 test for seropositives.
Conclusions: Seroconversion after SARS-CoV-2 infection confers protection against reinfection lasting at least 8 months. These findings could help global health authorities establishing priority for vaccine allocation.
Keywords: COVID-19; SARS-CoV-2; antibody; protection; reinfection.
【저자키워드】 COVID-19, SARS-CoV-2, antibody, protection, reinfection., 【초록키워드】 Vaccine, coronavirus, immune response, pandemic, antibody, SARS-COV-2 infection, Infection, immunodeficiency, Gender, Reinfection, body mass index, Seroconversion, Serosurvey, serological assays, Effectiveness, age, Follow-up, infection rate, incidence, BMI, respiratory, serological, Switzerland, smoking status, SARS-CoV-2 infections, seronegative, Clinical practice, retrospective, health authorities, Health authority, body mass, Standard deviation, acute respiratory syndrome, Participants, Primary outcome, follow-up period, acute respiratory syndrome coronavirus, 95% confidence interval, individual, hazard, priority, help, participant, positive, seropositive participants, seropositive individuals, seropositive subjects, SARS-CoV-2 test, seroprevalence survey, controls, selected, conducted, reduction in, seropositive individual, seropositive subject, 【제목키워드】 coronavirus 2, Matched,