Sufficient COVID-19 quarantine and testing on international travelers to forestall cross-border transmission after China's removal of the zero-COVID policy in early 2023.

ABSTRACT

BACKGROUND: Removal of zero-COVID restrictions in China led to a surge in COVID-19 cases. In response, countries imposed restrictions on Chinese travelers. However, border policies imposed may not have been informed by accurate data and may not have provided substantial benefits. METHODS: We analyzed quarantines sufficient to prevent additional in-country transmission for February 13-19, 2023 based on World Health Organization (WHO) and self-reported infections to estimate prevalence. RESULTS: We have shown that self-reported prevalence data indicated more stringent border restrictions compared to WHO-published prevalence statistics. No travel restrictions were required for Singapore, South Korea, and Japan so that infections would not be greater than with complete border closure. However, a 1-, 2-, and 3-day quarantine were indicated for England, Germany, and Scotland respectively. A 10-, 13-, and 14-day quarantine were required for Italy, France, and the Philippines, respectively, to prevent an increase in within-country infections due to travel. Vietnam and Thailand required a complete border shutdown. CONCLUSION: Our results demonstrated the necessity for accurate and timely reporting of pandemic statistics to prevent an increase in viral spread. Through the minimum quarantine analysis, countries can use science to determine policy, minimize international friction, and improve the cost-efficiency of interventions.