Evaluation of risk factors for developing COVID-19 in healthcare professionals working at two university hospitals in Turkey.

Background: Healthcare workers (HCWs) were seriously affected by the coronavirus disease 2019 (COVID-19). It is a priority to protect HCWs against COVID-19 and ensure the continuity of the health care system.

Objective: To evaluate the risk factors for COVID-19 in HCWs and the effectiveness of the measures taken on protection.

Methods: A nested case-control study was conducted in two hospitals serving on the same campus which are affiliated with a university from Turkey, between 03.12.2020 and 05.22.2020. We aimed to recruit three controls working in the same unit with the cases diagnosed with COVID-19 by polymerase chain reaction (PCR) and whose SARS-CoV-2 PCR test is negative. Self-reported data were collected from the HCWs by the face-to-face method. Descriptive and analytical methods were used and a logistic regression model was built.

Results: The study was completed with 271 HCWs, 72 cases, and 199 controls. Household contact with a COVID-19 patient or a patient with symptoms compatible with COVID-19 was found to be significantly higher in the cases than in the controls (p = 0.02, p < 0.001). When the measures for control the COVID-19 were analyzed, using a medical mask (OR = 0.28, 95% confidence interval = 0.11-0.76, p = 0.01) by COVID-19 patient and using the respiratory mask by HCWs (OR = 0.13, 95% CI = 0.03-0.52, p = 0.004) during close contact was found to be protective against COVID-19 transmission.

Conclusion: This study showed an association with using medical masks by the patients as an important protective precaution for the transmission of COVID-19 to HCWs. Respiratory masks should be used by HCWs while in close contact with COVID-19 patients regardless of aerosol-producing procedures.