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