# Antibody Responses to SARS-CoV-2 among Health Care Workers in North-Eastern Tanzania

## TL;DR

This study found that most healthcare workers in Tanzania had SARS-CoV-2 antibodies, suggesting high exposure to the virus despite low vaccination rates.

## Contribution

The study provides new data on SARS-CoV-2 antibody prevalence among healthcare workers in a low-vaccination setting in Africa.

## Key findings

- 99.6% of healthcare workers had positive SARS-CoV-2 IgG antibodies, with 64.5% showing strong seropositivity.
- Factors like cadre, sex, and hand hygiene practices significantly influenced antibody concentrations.
- Only 37.9% of participants reported being vaccinated against COVID-19.

## Abstract

Health Care Workers (HCWs) have been playing crucial role in treating patient with COVID-19. They have a higher occupational risk of contracting the disease than the general population, and a greater chance of them transmitting the disease to vulnerable patients under their care. Given the scarcity of HCWs and low COVID-19 vaccine acceptance in Africa, it is essential that HCWs are seroprotected and their exposure to COVID-19 minimized Objective: To determine IgG antibody response to SARS-CoV-2 among HCWs of a tertiary hospital in North Eastern, Tanzania.

This cross-sectional study was carried out among 273 HCWs at Kilimanjaro Christian Medical Centre (KCMC), a tertiary, zonal referral hospital in Tanzania’s North Eastern region. Stratified sampling was used to select study participants. Data were obtained from each consenting participant using a validated questionnaire. Blood samples were collected for SARS-CoV-2 IgG antibody quantification using an indirect ELISA test. RedCap software was used to manage data. Statistical analysis was done using STATA statistical software version 15 and GraphPad Prism v 9.0. A p-value of <0.05 was considered the cut-off for statistical significance.

Among 273 HCWS, 37.9 % reported receiving the COVID-19 vaccine. Except for one person, all of the participants (99.6%) had SARS-CoV-2 IgG antibody concentrations that were positive, with 64.5% of them having strong seropositivity. Cadre, sex, BMI, smoking status, adherence to recommended hand hygiene practices and COVID-19 patient interactions were significant predictors of variation of median SARS-CoV-2 antibody concentration. Age, usage of personal protective equipment, history of previously testing PCR positive for COVID-19, and total number of COVID-19 patients exposed were found to cause no statistically significant variation in median antibody concentration among participants.

This study identified a high seroprevalence of SARS-CoV-2 antibodies among healthcare workers in the study setting, indicating significant exposure to SARS-CoV-2 virus, despite only a minority of them being vaccinated. These findings underscore the need for robust communicable disease prevention strategies including; regular screening and pathogen surveillance to better prepare for potential future pandemics. Such measures are critical to mitigating the substantial impacts on health care workers and ensuring the resilience of the healthcare system.