To examine the appropriateness of the decision to quarantine healthcare workers (HCWs) exposed to coronavirus disease 2019 (COVID-19).

Retrospective cohort study.

A tertiary-care medical center in Israel.

HCWs exposed to a coworker infected with severe acute respiratory coronavirus virus 2 (SARS-CoV-2).

Quarantined and nonquarantined HCWs were followed for up to 1 month following exposure and their COVID-19 status was determined. The validity of the decision to quarantine was assessed.

In total, 2,595 HCWs exposed to 419 confirmed index cases were studied. Of the contact cases, 752 HCWs were quarantined and 1,843 HCWs were not. Of those quarantined, 36 became SARS-CoV-2 positive (4.7%). Among those who were not quarantined, only 13 (0.7%) became SARS-CoV-2 positive, which translated to a sensitivity of 73.5% and a specificity of 71.9% for the decision to quarantine (positive and negative predictive values: 4.7% and 99.3%, respectively). Controlling for confounders, the decision to quarantine the HCW by the Israeli Ministry of Health guidelines was associated with a significant risk of becoming SARS-CoV-2 positive (RR, 3.83; 95% CI, 1.98–7.36; P = .001). If a nonselective policy was used, 11,700 working days would have been lost (902 working days lost per positive case).

An efficient and tight system of HCW contact investigations served its purpose in our hospital during the COVID-19 pandemic. This study was based on HCW reports and reported adherence to safety regulations, and these findings are relevant to the massive pandemic waves due to the SARS-CoV-2 α (alpha) variant. These Methods demonstrate an effective way of handling risk without causing damage due to arbitrary risk-control measures.