Travel‐related control measures to contain the COVID‐19 pandemic: a rapid review

Cochrane published a rapid review in September 2020 where the effectiveness of travel‐related control measures during the COVID‐19 pandemic on infectious disease and screening‐related outcomes were assessed.

The evidence current up to 26 June 2020 found 25 studies on COVID‐19, 10 on SARS and one on both SARS and MERS. Studies took place across the world except for Africa and the eastern Mediterranean.

Twelve studies (11 modelling studies, 1 observational study) on COVID‐19 found that restricting cross‐border travel at the beginning of an outbreak may reduce new cases by a minimum of 26% to a maximum of 90%, may reduce the number of deaths, may reduce the time to an outbreak by between 2 to 26 days, and may reduce the spread and risk of an outbreak. There was also a reduction in imported or exported cases and in growth of the epidemic.

The study found 12 studies (6 modelling studies, 6 observational studies) on entry or exit screening, with and without quarantine, to contain the spread of COVID‐19. Based on data from three modelling studies, there may be a delay in the time to an outbreak, and between 10% to 53% of infected travellers would be detected. However, the results from the observational studies varied considerably, and were uncertain about the proportion of people identified accurately as having COVID‐19 from these studies.

Only one modelling study examined quarantine measures for COVID‐19. It found fewer new cases due to imported cases where 14‐day quarantine was in place.

The confidence in these results is limited for several reasons. Most studies were not based on real‐life epidemics but on mathematical predictions. Their results depended on the assumptions that they made, not on real‐life data. Also, the studies were very different from each other and their results would probably vary according to the stage of the epidemic, the amount of cross‐border travel, other measures undertaken locally, and the extent of implementation and enforcement. Results of entry and exit screening studies might vary according to the screening method used and the level of infection among travellers. Also, some studies were published as ‘preprints’, which means they did not undergo the rigorous checks of most peer‐reviewed studies.

Overall, travel‐related control measures may help to limit the spread of disease across national borders. Cross‐border travel restrictions are probably more effective than entry and exit screening. Screening is likely to be more effective if combined with other measures, such as quarantine and observation. The review found very little information on travel‐related quarantine as a stand‐alone measure and no information on costs or negative effects.

The review can be accessed at https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013717/full