Cumulative incidence of SARS-CoV-2 and associated risk factors among healthcare workers: a cross-sectional study in the Eastern Cape, South Africa

David Stead; Oladele Vincent Adeniyi; Mandisa Singata-Madliki; Shareef Abrahams; Joanne Batting; Eloise Jelliman; Andrew Parrish

doi:10.1136/bmjopen-2021-058761

Cumulative incidence of SARS-CoV-2 and associated risk factors among healthcare workers: a cross-sectional study in the Eastern Cape, South Africa

BMJ Open. 2022 Mar 18;12(3):e058761. doi: 10.1136/bmjopen-2021-058761.

Authors

David Stead^{1

2}, Oladele Vincent Adeniyi^{3

4}, Mandisa Singata-Madliki^{5

6}, Shareef Abrahams⁷, Joanne Batting⁵, Eloise Jelliman⁸, Andrew Parrish^{9

2}

Affiliations

¹ Department of Internal Medicine, Walter Sisulu University Faculty of Health Sciences, Mthatha, Eastern Cape, South Africa dfstead@gmail.com.
² Internal Medicine, Frere Hospital, East London, Eastern Cape, South Africa.
³ Department of Family Medicine, Walter Sisulu University Faculty of Health Sciences, Mthatha, Eastern Cape, South Africa.
⁴ Department of Family Medicine, Cecilia Makiwane Hospital, Mdantsane, Eastern Cape, South Africa.
⁵ Department of Public health, University of Fort Hare East London Campus, East London, South Africa.
⁶ Obstetrics and Gynaecology, Wits University, Johannesburg-Braamfontein, Gauteng, South Africa.
⁷ Division of Microbiology, Department of Pathology, National Health Laboratory Service, Port Elizabeth, South Africa.
⁸ Radiology, Frere Hospital, East London, Eastern Cape, South Africa.
⁹ Department of Internal Medicine, Walter Sisulu University Faculty of Health Sciences, Mthatha, Eastern Cape, South Africa.

Abstract

Objectives: This study assesses the cumulative incidence of SARS-CoV-2 infection among healthcare workers (HCWs) during South Africa's first wave and examines the associated demographic, health-related and occupational risk factors for infection.

Methods: Multistage cluster sampling was used in a cross-sectional study to recruit 1309 HCWs from two academic hospitals in the Eastern Cape, South Africa over 6 weeks in November and December 2020. Prior test results for SARS-CoV-2 PCR and participants' characteristics were recorded while a blood sample was drawn for detection of IgG antibodies against SARS-CoV-2 nucleocapsid protein. The primary outcome measure was the SARS-CoV-2 cumulative incidence rate, defined as the combined total of positive results for either PCR or IgG antibodies, divided by the total sample. The secondary outcome was significant risk factors associated with infection.

Results: Of the total participants included in the analysis (n=1295), the majority were women (81.5%), of black race (78.7%) and nurses (44.8%). A total of 390 (30.1%) HCWs had a positive SARS-CoV-2 PCR result and SARS-CoV-2 antibodies were detected in 488 (37.7%), yielding a cumulative incidence of 47.2% (n=611). In the adjusted logistic regression model, being overweight (adjusted OR (aOR)=2.15, 95% CI 1.44 to 3.20), obese (aOR=1.37, 95% CI 1.02 to 1.85) and living with HIV (aOR=1.78, 95% CI 1.38 to 2.08) were independently associated with SARS-CoV-2 infection. There was no significant difference in infection rates between high, medium and low COVID-19 exposure working environments.

Conclusions: The high SARS-CoV-2 cumulative incidence in the cohort was surprising this early in the epidemic and probably related to exposure both in and outside the hospitals. To mitigate the impact of SARS-CoV-2 among HCWs, infection prevention and control strategies should target community transmission in addition to screening for HIV and metabolic conditions.

Keywords: COVID-19; health & safety; infection control.

Publication types

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

MeSH terms

COVID-19* / diagnosis
COVID-19* / epidemiology
Cross-Sectional Studies
Female
Health Personnel
Humans
Incidence
Male
Risk Factors
SARS-CoV-2*
South Africa / epidemiology