High Seroprevalence of SARS-CoV-2 in Mwanza, Northwestern Tanzania: A Population-Based Survey

Helmut A Nyawale; Nyambura Moremi; Mohamed Mohamed; Johnson Njwalila; Vitus Silago; Manuel Krone; Eveline T Konje; Mariam M Mirambo; Stephen E Mshana

doi:10.3390/ijerph191811664

High Seroprevalence of SARS-CoV-2 in Mwanza, Northwestern Tanzania: A Population-Based Survey

Int J Environ Res Public Health. 2022 Sep 16;19(18):11664. doi: 10.3390/ijerph191811664.

Authors

Helmut A Nyawale¹, Nyambura Moremi², Mohamed Mohamed³, Johnson Njwalila¹, Vitus Silago¹, Manuel Krone⁴, Eveline T Konje⁵, Mariam M Mirambo¹, Stephen E Mshana¹

Affiliations

¹ Department of Microbiology and Immunology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza P.O. Box 1464, Tanzania.
² National Public Health Laboratory, Dar es Salaam P.O. Box 9083, Tanzania.
³ East Central and Southern Africa Health Community, Arusha P.O. Box 1009, Tanzania.
⁴ Infection Control and Antimicrobial Sterwardship Unit, University Hospital Wuerzburg, 97080 Wüerzburg, Germany.
⁵ Department of Epidemiology and Biostatistics, School of Public Health, Catholoic University of Health and Allied Sciences, Mwanza P.O. Box 1464, Tanzania.

Abstract

The transmission of the SARS-CoV-2 virus, which causes COVID-19, has been documented worldwide. However, the evidence of the extent to which transmission has occurred in different countries is still to be established. Understanding the magnitude and distribution of SARS-CoV-2 through seroprevalence studies is important in designing control and preventive strategies in communities. This study investigated the seropositivity of the SARS-CoV-2 virus antibodies in the communities of three different districts in the Mwanza region, Tanzania. A household cross-sectional survey was conducted in September 2021 using the modified African Centre for Disease and Prevention (ACDC) survey protocol. A blood sample was obtained from one member of each of the selected households who consented to take part in the survey. Immunochromatographic rapid test kits were used to detect IgM and IgG SARS-CoV-2 antibodies, followed by descriptive data analysis. Overall, 805 participants were enrolled in the study with a median age of 35 (interquartile range (IQR):27-47) years. The overall SARS-CoV-2 seropositivity was 50.4% (95%CI: 46.9-53.8%). The IgG and IgM seropositivity of the SARS-CoV-2 antibodies was 49.3% and 7.2%, respectively, with 6.1% being both IgG and IgM seropositive. A history of runny nose (aOR: 1.84, 95%CI: 1.03-3.5, p = 0.036), loss of taste (aOR: 1.84, 95%CI: 1.12-4.48, p = 0.023), and living in Ukerewe (aOR: 3.55, 95%CI: 1.68-7.47, p = 0.001) and Magu (aOR: 2.89, 95%CI: 1.34-6.25, p= 0.007) were all independently associated with SARS-CoV-2 IgM seropositivity. Out of the studied factors, living in the Ukerewe district was independently associated with IgG seropositivity (aOR 1.29, CI 1.08-1.54, p = 0.004). Twenty months after the first case of COVID-19 in Tanzania, about half of the studied population in Mwanza was seropositive for SARS-CoV-2.

Keywords: COVID-19; Mwanza; SARS-CoV-2; Tanzania; antibodies; seroprevalence.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Antibodies, Viral
COVID-19* / epidemiology
Cross-Sectional Studies
Humans
Immunoglobulin G
Immunoglobulin M
SARS-CoV-2*
Seroepidemiologic Studies
Tanzania / epidemiology

Substances

Antibodies, Viral
Immunoglobulin G
Immunoglobulin M

Grants and funding

The study received no formal funding. The kits used in this study were donated by the KH Medical Company. The APC was funded by Catholic University of Health and Allied Sciences, Mwanza, Tanzania which was provided to Mshana S.E.