Abstract
COVID-19 exposure in Central Asia appears underestimated and SARS-CoV-2 seroprevalence data are urgently needed to inform ongoing vaccination efforts and other strategies to mitigate the regional pandemic. Here, in a pilot serologic study we assessed the prevalence of SARS-CoV-2 antibody-mediated immunity in a multi-ethnic cohort of public university employees in Karaganda, Kazakhstan. Asymptomatic subjects (n = 100) were recruited prior to their first COVID-19 vaccination. Questionnaires were administered to capture a range of demographic and clinical characteristics. Nasopharyngeal swabs were collected for SARS-CoV-2 RT-qPCR testing. Serological assays were performed to detect spike (S)-reactive IgG and IgA and to assess virus neutralization. Pre-pandemic samples were used to validate the assay positivity thresholds. S-IgG and -IgA seropositivity rates among SARS-CoV-2 PCR-negative participants (n = 100) were 42% (95% CI [32.2-52.3]) and 59% (95% CI [48.8-69.0]), respectively, and 64% (95% CI [53.4-73.1]) of the cohort tested positive for at least one of the antibodies. S-IgG titres correlated with virus neutralization activity, detectable in 49% of the tested subset with prior COVID-19 history. Serologically confirmed history of COVID-19 was associated with Kazakh ethnicity, but not with other ethnic minorities present in the cohort, and self-reported history of respiratory illness since March 2020. Overall, SARS-CoV-2 exposure in this cohort was ~15-fold higher compared to the reported all-time national and regional COVID-19 prevalence, consistent with recent studies of excess infection and death in Kazakhstan. Continuous serological surveillance provides important insights into COVID-19 transmission dynamics and may be used to better inform the regional public health response.
【초록키워드】 COVID-19, public health, SARS-CoV-2, IgG, vaccination, pandemic, Immunity, Clinical characteristics, Infection, Respiratory illness, Asia, Prevalence, RT-qPCR, Cohort, SARS-CoV-2 seroprevalence, COVID-19 vaccination, serological assays, nasopharyngeal swabs, IgA, Virus neutralization, death, Seropositivity, Swab, serological surveillance, respiratory, Antibody-mediated immunity, Kazakhstan, COVID-19 transmission, capture, Questionnaires, 95% CI, subject, asymptomatic subjects, effort, participant, titre, demographic and clinical characteristics, National, positive, PCR-negative, thresholds, Administered, mitigate, Serologically, tested, performed, detect, collected, recruited, reported, detectable, appear, provide, were used, correlated, subset, Continuous, the antibodies, 【제목키워드】 SARS-CoV-2 seroprevalence, COVID-19 vaccination,