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

Abstract

Background: 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.
Methodology: 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.
Results: 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.
Conclusion: 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.