Real-World Effectiveness of International Border Health Interventions in Mitigating the Spread of SARS-CoV-2 During the First Years of the COVID-19 Pandemic, 2020-2023: A Systematic Review

Many vaccine-related and nonpharmaceutical interventions, including travel-related measures, were established to mitigate the spread of SARS-CoV-2. Some countries began to impose measures on travelers from Wuhan, China, the location of the first identified COVID-19 cases, as early as December 31, 2019. The objective of this systematic review was to assess real-world effectiveness of travel-related measures in mitigating the international spread of SARS-CoV-2 during the declared public health emergency from 2020 to 2023. Inclusion criteria encompassed interventional and observational studies describing international travel-related mitigation measures and their effect on cases, hospitalizations, or deaths. Modeling studies were excluded. Electronic searches were performed using Embase (OVID), Global Health (OVID), CINAHL (EBSCOHost), Cochrane Library, Scopus, Medline (OVID), and World Health Organization COVID-19 Global Literature to identify studies published from January 1, 2020, through February 24, 2023. The ROBINS-I tool was used to assess risk of bias. A total of 37 observational studies met inclusion criteria for the review. Of these, 9 (24%) described quarantine-related interventions, 4 (11%) testing-only interventions, 6 (16%) border closures, 5 (14%) vaccination/immunity-based interventions, and 13 (35%) multiple interventions. Risk of bias was judged to be serious or critical for 14 (38%) of the studies. Comparison groups and outcomes were heterogeneous, but most described a positive effect on improving measured decreasing outcomes of interest. Although significant biases may be associated with these observational studies, international travel-related measures may have been effective in temporarily mitigating the spread of SARS-CoV-2 early in the pandemic. However, many measures became less effective as SARS-CoV-2 spread globally. In future pandemics, countries should consider designing evaluation strategies when measures are planned, before implementation.