High Seroprevalence of anti-SARS-CoV-2 antibodies among Ethiopian healthcare workers

Abstract

COVID-19 pandemic has a devastating impact on the economies and health care system of sub-Saharan Africa. Healthcare workers (HWs), the main actors of the health system, are at higher-risk because of their occupation. Serology-based estaimates of SARS-CoV-2 infection among HWs represent a measure of HWs level of exposure to the virus and a guide to the prevalence of SARS-CoV-2 in the community. This information is currently lacking in Ethiopia. This study aims to develop an in-house antibody testing assay and assess the prevalence of SARS-CoV-2 antibodies among Ethiopian high-risk front-line HWs. A cross-sectional seroprevalence study was conducted among HWs in five public hospitals located in different geographic regions of Ethiopia. Socio-demographic and clinical data were collected using questionnaire-based interviews. From consenting HWs, blood samples were collected between December 2020 and February 2021, the period between the two peaks of COVID-19 in Ethiopia. The collected sera were tested using an in-house immunoglobin G (IgG) enzyme-linked immunosorbent assay (ELISA) for SARS-CoV-2 specific antibodies on sera collected from HWs. Of 1,997 HWs who provided a blood sample, demographic and clinical data, 50.5% were female, 74.0% had no symptoms compatible with COVID-19, and 29.0% had history of contact with suspected or confirmed patient with SARS-CoV-2 infection. The overall seroprevalence was 39.6%. The lowest (24.5%) and the highest (48.0%) seroprevalence rates were found in Hiwot Fana Specialized Hospital in Harar and ALERT Hospital in Addis Ababa, respectively. Of the 821 seropositive HWs, 224(27.3%) had history of symptoms consistent with COVID-19. A history of close contact with suspected/confirmed COVID-19 cases was strongly associated with seropositivity (Adjusted odds Ratio (AOR) =1.4, 95% CI 1.1-1.8; p=0.015). High SARS-CoV-2 seroprevalence levels were observed in the five Ethiopian hospitals. These findings highlight the significant burden of asymptomatic infection in Ethiopia, and may reflect the scale of transmission in the general population.

SARS-CoV-2 infection and antibody seroprevalence in routine surveillance patients, healthcare workers and general population in Kita region, Mali: an observational study 2020–2021

“…This could be explained by a multitude of interlinking factors. High levels of asymptomatic cases, both for the general population and HCWs, have been documented in African as well as global studies 11 17–21. As our study’s active infection testing selected suspected cases of COVID-19 only, we could have missed a large proportion of asymptomatic cases.…”

“…A recent Zambian postmortem study suggested that many people who die have an undiagnosed SARS-CoV-2 infection 4. Various studies have determined the seroprevalence in Africa 5–13. A recent systematic review has estimated it to be approximately 22%, with highest seroprevalence in central Africa 5.…”

Epidemiology and psychosocial assessment of COVID-19 among workersof the Nigeria Centre for Disease Control infected with COVID-19

“…12 In addition, a study conducted in 5 different hospitals in Ethiopia showed 39.6% seropositivity for COVID-19 among 1997 HCWs. 13 Also, similar studies conducted among HCWs in Somalia and Egypt showed high rate of COVID-19 transmission. 14,15 Nonetheless, considering that this is a novel infection with transmission patterns and sources yet to be fully understood, it is expected that the risk of infection might be significantly high within such frontline centres.…”

Pre-pandemic cross-reactive humoral immunity to SARS-CoV-2 in Africa: systematic review and meta-analysis

“…After screening 38 studies (Figure 1) and excluding 16 (Supplementary references), 22 studies were eligible (18 retrieved from the main search and another 4 retrieved from cited/citation searches). [3][4][5][6][7][8][9][10][11][12][13][14][22][23][24][25][26][27][28][29][30][31] 19 studies were published in peer-reviewed journals and 3 were preprints. Other studies screened in-depth and excluded are shown in Supplementary References along with the reason for exclusion.…”