Update Alert 3: Epidemiology of and Risk Factors for Coronavirus Infection in Health Care Workers

This is the third monthly update alert for a living rapid review on the epidemiology of and risk factors for coronavirus infection in health care workers (HCWs) (1). Searches were updated from 25 June 2020 to 24 July 2020, using the same search strategies as the original review. The update searches identified 2010 citations. We applied the same inclusion criteria used for the prior update, with previously described protocol modifications to focus on higher-quality evidence (2). Eight studies, all on SARS-CoV-2 infection, were added for this update (3–10).

The original rapid review included 15 studies on the burden of SARS-CoV-2 infection (1); 34 studies were added in prior updates (2, 11) (Supplement Tables 1 and 2). Three cohort studies (7–9) and 2 cross-sectional studies (3, 6) on the burden of SARS-CoV-2 infection were added for this update. Of the new studies, 1 was conducted in the United States (3) and the others in Europe: Belgium (8), Italy (6), Germany (9), and Greece (7). The proportion of HCWs with COVID-19 was 1.9% in 1 study (3); the proportion with SARS-CoV-2 infection ranged from 2.2% to 12.6% in 3 studies (6, 8, 9); and the proportion with SARS-CoV-2 seropositivity was 7.6% in 1 study (10). Among HCWs with SARS-CoV-2 infection, the proportion hospitalized ranged from 0% to 1.7% in 3 studies (n = 5839), with no deaths (6–8). All estimates were within previously described ranges.

The original rapid review included 31 studies on risk factors for SARS-CoV-2 infection (1); 12 were added in prior updates (2, 11). For this update, 7 new studies (n = 8762) evaluated risk factors for SARS-CoV-2 infection in HCWs (Supplement Table 3) (4–10). One case–control study found performing endotracheal intubation and never using personal protective equipment was associated with increased risk for SARS-CoV-2 infection in a multivariate analysis (4). Use of masks, caps, gowns, shoe covers, gloves, or face shields were associated with decreased risk in univariate analysis but were not retained in the multivariate model. Limitations included potential recall bias, failure to address potential collinearity, and limited measurement and control of exposures. A prospective cohort study found high-risk exposure associated with increased risk for a COVID-19 diagnosis versus moderate- or low-risk exposure in an adjusSupppted analysis; exposure was categorized using an unvalidated method, on the basis of mask use by the infected patient and personal protective equipment use by the HCW (7). Four studies (4, 7, 9, 10) found no association between sex and risk for SARS-CoV-2 infection, and 5 studies (5, 6, 8–10) reported inconsistent findings for the risk for SARS-CoV-2 infection in nurses versus physicians. Results for risk factors updated with these studies were judged to be consistent with the original rapid review and prior update (Supplement Tables 4 to 9).