Investigation of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infections among health care workers - Lusaka District, Zambia, April-June 2020

Introduction: Zambia is experiencing an epidemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that causes coronavirus disease 2019 (COVID-19). Infections initially sporadic, but community transmission began to occur widely in late June 2020. Over 100 health care workers (HCWs) reported infected with SARS-CoV-2 in Lusaka District. We investigated factors associated with SARS-CoV-2 infections among HCWs in four hospitals in Lusaka District during April to June 2020. Methods: Case control study among HCWs with confirmed SARS-CoV-2 infections at Levy Mwanawasa Hospital, Cancer Disease Hospital, Chilenje First level Hospital, and Women and Newborn Hospital in April to June 2020. Controls drawn from HCWs working in a department within 14 days before a positive test of cases. Standardized questionnaire assessing demographics, medical history, exposures, and infection prevention practices administered. Logistic regression conducted to assess associations with SARS-CoV-2 infection, with odds ratios (ORs) and 95% confidence intervals (CIs) reported. Results: Forty-three cases occurred in four facilities from April through June 2020. We interviewed 39 cases and 101 controls. Median age was 33 years (interquartile range: 28, 38). Twenty-nine (74%) cases self-reported being asymptomatic. Most (25(65.8%)) cases tested positive during HCW screening with no known HCW index case. Unknown exposure status in facilities had increased odds of acquiring SARS-CoV-2 compared to known exposure (OR = 4.5 (95% CI: 1.73, 11.9)). Low adherence to handwashing (OR=4.53 (95% CI: 1.74, 11.8)) and inadequate use of personal protective equipment (OR=2.87 (1.20, 6.87)) increased odds of having SARS-CoV-2. Conclusion: Low adherence to personal protective measures like hand washing, PPE use and absence of knowledge about potential SARS-CoV-2 exposures in health facilities suggest that transmission could have occurred in health facilities. Routine HCW screening for early identification and isolation of cases to minimise nosocomial transmission is recommended