5. GRADE evidence profile for the effectiveness of quarantine for individuals travelling from a country with a declared COVID‐19 outbreak compared to no quarantine.
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Patient or population: individuals travelling from regions with a declared COVID‐19 outbreak Settings: travellers from China, UK, Spain, Turkey Intervention: quarantine of travellers Comparison: no quarantine of travellers | ||||||||
| Outcome | Number of studies | Risk of bias | Indirectness | Imprecision | Inconsistency | Other considerations | Summary effect size/outcome | Certainty of the evidence |
| Incidence | 4 observational studies (Arima 2020; Hsieh 2005; ; Lytras 2020; Wang 2007) | Seriousa | Indirectb | Precise | Inconsistentc | None |
COVID‐19 Arima 2020: from 566 travellers arriving in Japan from Hubei Province, 12 had COVID‐19 (2.1%). Seven of them were identified upon arrival by entry screening, but five were identified during 14‐day quarantine. Lytras 2020: from 357 travellers from the UK, 13 were SARS‐CoV‐2 positive (3.6%, 95% CI 2.0 to 6.1). From 394 travellers from Spain, 25 were positive (6.3, 95% CI 4.1 to 9.2), and two of 32 returnees from Turkey (6.3, 0.9 to 20.8). SARS Wang 2007 reported that 56 of 95,271 quarantined travellers developed SARS (0.0006%). Hsieh 2005 reported that 0 out of 95,828 quarantined travellers developed SARS (0%). |
Very low |
| 1 modelling study (Hsieh 2007) | Very seriousd | Indirecte | N/A | Inconsistentc | None | Hsieh 2007: if all 17 unquarantined imported cases had been quarantined, 280 SARS cases could have been averted. Based on their data source, out of the more than 95,000 quarantined people, only two developed SARS. If these two individuals had not been quarantined, 29 additional cases would have occurred. | Very low | |
| Onward transmission | No evidence | |||||||
| Mortality | 1 modelling study (Hsieh 2007) | Seriousd | Indirecte | N/A | Inconsistentc | None | Hsieh 2007: if all 17 unquarantined imported cases had been quarantine, 48 deaths could have been averted. Two people under quarantine developed SARS. By placing them under quarantine 5 additional deaths could be averted. | Very low |
| Costs | No evidence | |||||||
| CI: confidence interval; COVID‐19: coronavirus disease 2019; N/A: not applicable; SARS‐CoV‐2: severe acute respiratory syndrome coronavirus 2 | ||||||||
aDowngraded one step for risk of bias because three of the observational studies had a moderate risk of bias. bDowngraded one step for indirectness because observational studies did not report incidence of new cases or new cases averted but number of quarantined travellers who developed COVID‐19; two studies provided indirect evidence on SARS. cDowngraded one step because a retrospective study (Hsieh 2005), not specifically reporting incidence of new cases but number of quarantined travellers who developed SARS, reported 0 SARS cases within more than 95,000 quarantined travellers. This differs slightly from the data used by Hsieh 2007: 2 SARS cases out of more than 95,000 quarantined travellers. dDowngraded two steps for risk of bias: one because we had moderate concerns regarding quality and one because model parameters are accompanied by uncertainties. eDowngraded one step for indirectness because the study used SARS data, which does not reflect the presymptomatic infectiousness of COVID‐19.