Border closure and travel restrictions to control the spread of COVID-19: an update to a Cochrane review

BackgroundCOVID-19 has proven to be more difficult to manage for many reasons including its high infectivity rate. One of the potential ways to limit its spread is by limiting free travel across borders, including via air travel. The objective of this systematic review is to identify, critically-appraise and summarize evidence on border closures and travel restrictions. MethodsThis review is based on the Cochrane review: "International travel-related control measures to contain the COVID-19 pandemic" and followed the same methodology. In brief, we searched for clinical and modelling studies in general health and COVID-19-specific bibliographic databases. The primary outcome categories were (i) cases avoided, (ii) cases detected, and (iii) a shift in epidemic development. Secondary outcomes were other infectious disease transmission outcomes, healthcare utilisation, resource requirements and adverse effects if identified in studies assessing at least one primary outcome. ResultsWe included 43, mostly modelling, studies that met our inclusion criteria. Fourteen new studies were identified in the updated search, as well as updated companions (e.g., peer-reviewed publications that were previously only available as pre-prints). Most studies were of moderate to high quality. The added studies did not change the main conclusions of the Cochrane review nor the quality of the evidence (very low to low certainty). However, it did add to the evidence base for most outcomes. ConclusionsWeak evidence supports the use of border closures to limit the spread of COVID-19 via air travel. Real-world studies are required to support these conclusions.