This systematic review showed that quarantine is important in reducing incidence and mortality with respect to COVID-19, and that early implementation it with other public health measures is important to ensure effectiveness.

The Cochrane Collaboration conducted a rapid review to assess the effects of quarantine of individuals who had contact with confirmed cases of COVID‐19, who arrived from countries with a declared outbreak, or who lived in regions of high transmission. They included cohort studies, case‐control‐studies, case series, time series, interrupted time series, and mathematical modeling studies. They also included studies on SARS and MERS as indirect evidence.

They included 29 studies: 10 modeling studies, 4 observational studies, and 15 modeling studies on SARS and MERS. The certainty of the evidence was low to very low.

Modeling studies consistently reported a benefit of quarantine measures with low‐certainty evidence. Very low‐certainty evidence suggests that the earlier measures are put into place, the greater the cost savings. Very low‐certainty evidence showed that quarantine of travelers from a country with a declared outbreak was small. When the models combined quarantine with other measures, like school closures, travel restrictions, and social distancing, the models demonstrated a larger effect than individual measures alone with low‐certainty evidence.