Sero-prevalence of SARS-CoV-2 in certain cities of Kazakhstan

Seroprevalence studies are needed to determine the cumulative prevalence of SARS-CoV-2 infection and to develop pandemic mitigation strategies. Despite the constant monitoring and surveillance, the true level of infection in the population of Kazakhstan remains unknown. The aim of this study was to determine the sero-prevalence of SARS-CoV-2 in the main cities of Kazakhstan.

The research was conducted as a cluster-randomized cross-sectional national household study in three cities of Kazakhstan. The study covered the period: from October 24, 2020, to January 11, 2021. A total of 5739 people took part in the study. All participants agreed to be tested for antibodies to IgM/IgG. Demographic characteristics were analyzed. The presence of symptoms of respiratory diseases and the results of polymerase chain reaction (PCR) testing were determined. The antibodies to the SARS-CoV-2 virus were detected using the method of enzyme-linked immunosorbent assay (ELISA).

There was significant geographic variability with a higher prevalence of IgG/IgM antibodies to SARS-CoV-2 in Almaty 57.0%, in Oskemen 60.7% than in Kostanay 39.4%. There were no significant differences in prevalence between men and women (p ≥ 0.05). In Almaty, only 19% of participants with antibodies reported the presence of respiratory symptoms during a pandemic. At the same time, the percentage of patients with antibodies who had respiratory symptoms was 36% in Oskemen and 27% in Kostanay.

The findings indicate that despite reasonable level of seroprevalence, the country has not yet reached the baseline minimum of herd immunity scores. The prevalence estimates for asymptomatic or subclinical forms of the disease ranged from 64% to 81%. Thus, given that almost half of the population of Kazakhstan remains vulnerable, the importance of preventive strategies such as social distancing, the use of medical masks, and vaccination to protect the population from the transmission of SARS-CoV-2 is highly critical.