Objectives We aimed to compare the prevalence of asymptomatic COVID-19 among clinical staff in designated COVID-19 units vs. that among staff in similar units without known or suspected COVID-19 patients. Methods We conducted a cross-sectional survey of healthcare workers (HCW) in 8 Israeli general hospitals. The survey involved a questionnaire and a PCR test for SARS-CoV-2. We surveyed HCW in COVID-19 units and comparison units (internal medicine and cardiology) from April 30-May 7, 2020. Results There were 522 participants: 291 from COVID-19 units and 231 from comparison units. Only one participant (0.2%, 95% CI: 0.005%-1.1%) tested positive for SARS-CoV-2: an asymptomatic nurse on a COVID-19 unit. In participating COVID-19 units there were two symptomatic HCW with confirmed COVID-19 in the two weeks before the survey; both were infected by contact with a co-worker outside of the COVID-19 unit. Conclusions The low prevalence of asymptomatic COVID-19 among HCW, coupled with an absence of symptomatic COVID-19 acquired during patient care, suggest that. Israel's national guidelines for personal protective equipment, which are consistent with those of the World Health Organization, adequately protect HCW.

Background During the corona virus disease (COVID-19) epidemic, many healthcare workers (HCWs) were exposed to infected persons, leading to suspension from work. We describe a dynamic response to exposures of HCWs at the Hadassah Hospital, Jerusalem, to minimize the need for suspension from work. Methods We performed an epidemiological investigation following each exposure to a newly diagnosed COVID-19 patient or HCW; close contacts were suspended from work. During the course of the epidemic, we adjusted our isolation criteria according to the timing of exposure related to symptoms onset, use of personal protective equipment and duration of exposure. In parallel, we introduced universal masking and performed periodic SARS-CoV-2 screening for all hospital personnel. We analyzed the number of HCWs suspended weekly from work and those who subsequently acquired infection. Results In the 51 investigations conducted during March-May 2020, we interviewed 1095 HCWs and suspended 400 (37%) from work, most of them, 251 (63%), during the first two weeks of the outbreak. The median duration of exposure was 30 minutes (IQR, 15-120). Only 5/400 (1.3%) developed infection, all in the first two weeks of the epidemic. After introduction of universal masking and despite loosening the isolation criteria, none of the exposed HCWs developed COVID-19. Conclusions Relatively short exposures of HCWs, even if only either the worker or the patient wore a mask, probably poses a very low risk for infection. This allows us to perform strict follow-up of exposed HCWs in these exposures, combined with repeated testing, instead of suspension from work.