Background: Dynamics of antibody responses were investigated after a SARS-CoV-2 outbreak in a private company during the first wave of the pandemic. Methods: Workers of a sewing company (Lithuania) with known SARS-CoV-2 RT-PCR result during the outbreak (April 2020) were invited to participate in the study. Virus-specific IgG and IgM were monitored 2, 6 and 13 months after the outbreak via rapid IgG/IgM serological test and SARS-CoV-2 S protein-specific IgG ELISA. Results: Six months after the outbreak, 95% (CI 86–99%) of 59 previously infected individuals had virus-specific antibodies irrespective of the severity of infection. One-third of seropositive individuals had virus-specific IgM along with IgG indicating that IgM may persist for 6 months. Serological testing 13 months after the outbreak included 47 recovered individuals that remained non-vaccinated despite a wide accessibility of COVID-19 vaccines. The seropositivity rate was 83% (CI 69–91%) excluding one case of confirmed asymptomatic reinfection in this group. Between months 6 and 13, IgG levels either declined or remained stable in 31 individual and increased in 7 individuals possibly indicating an exposure to SARS-CoV-2 during the second wave of the pandemic. Conclusions: Detectable levels of SARS-CoV-2-specific antibodies persist up to 13 months after infection for the majority of the cases.
【저자키워드】 SARS-CoV-2, serological monitoring, IgG/IgM dynamics, longitudinal study, 【초록키워드】 serological test, IgG, IgM, pandemic, S protein, antibody, Antibody Response, Dynamics, Infection, Reinfection, Antibody responses, COVID-19 vaccines, Asymptomatic, Serological testing, outbreak, Seropositivity, second wave, SARS-CoV-2 RT-PCR, IgG ELISA, First wave, SARS-CoV-2-specific antibodies, specific antibodies, SARS-CoV-2 S protein, IgG and IgM, exposure to, SARS-CoV-2-specific antibody, infected individual, individual, worker, IgG levels, SARS-CoV-2 S, Severity of infection, seropositive individuals, specific IgM, virus-specific antibodies, Lithuania, Virus-specific IgG, investigated, remained, majority, declined, IgG level, seropositive individual, 【제목키워드】 Month,