a not downgraded for indirectness because one of the two studies was on COVID-19
Abbreviations: COVID-19: coronavirus disease 2019; NA: not applicable; SARS: severe acute respiratory syndrome

3.1.3 Comparative effectiveness of different types of quarantine (KQ 1a)

A prospective cohort study from Korea followed 116 hemodialysis patients who had to be quarantined because they were exposed to individuals with confirmed MERS infections.27 For a mean of 15 days, they underwent different types of quarantine: single-room quarantine (n=54), cohort quarantine (n=46), and self-imposed quarantine (n=16). None of the patients developed MERS symptoms, and no secondary transmission occurred. Because of the study’s small sample size, no conclusions about the comparative effectiveness of the different quarantine types can be drawn.

3.2 Effectiveness of quarantine for individuals traveling from a country with a declared COVID-19 outbreak (KQ 2)

3.2.1 Effectiveness of quarantine

We did not identify any study on quarantine for individuals traveling from a country with a declared COVID-19 outbreak, but did identify three SARS studies on the subject.
A retrospective cohort study28 and three modeling studies addressed the effectiveness of quarantine to reduce transmissions from individuals who traveled from regions with high transmission rates.36,43 Hsieh et al. used data from the 2003 SARS outbreak in Taiwan during which the Taiwanese government home-quarantined more than 95 000 travelers arriving at the borders from affected regions. Most quarantined people were confined to their homes for 10–14 days. The authors employed a SIR model with an estimated case fatality rate of 14·1%; the mean times of symptom onset to diagnosis were 1·20 days for the quarantined individuals and 2·89 days for those unquarantined. The results of the model showed that in the hypothetical scenario in which no one had been quarantined after arrival from a high transmission region, 511 additional SARS cases with 70 additional deaths would have occurred in Taiwan. In the database, 17 unquarantined imported cases could be traced (missed cases and cases before the quarantine’s implementation). If all 17 unquarantined imported cases would have been quarantined, 280 SARS cases and 48 deaths could have been averted. Of the more than 95 000 quarantined people, only two developed SARS. If these two individuals had not been quarantined, 29 additional cases and five deaths would have occurred. The authors acknowledge that caution should be exercised when viewing the numbers because the model did not account for the super-spreading events that occurred in Taiwan.
Using data from Taiwan, the second study employed a back-projection model without providing effect estimates for quarantine.43 The authors state that the model confirms the effectiveness of quarantine measures in Taiwan, including the implementation of quarantine for travelers from regions with high transmission rates. Table 4 presents the certainty of evidence ratings.
Table 4: Certainty of evidence ratings for the effectiveness of quarantine for travelers from regions with high transmission rates