Estimating the importation risk of mpox virus in 2022 to Hong Kong, China

Abstract

International air travel has been recognized as a crucial factor in the cross-regional transmission of monkeypox (now known as mpox) since this disease rapidly spread across the globe in May 2022. On September 6, 2022, Hong Kong SAR (HK) reported its first imported mpox case with travel history of the United States (US), Canada, and the Philippines. In this study, we estimated the importation risk to HK from 25 international departures from May 1 to September 6, 2022, based on the prevalence of pre-symptomatic mpox cases in the study regions, and time-varying flight mobility evaluated by aggregating multiple open-access air travel datasets (e.g., OpenSky, Aviation Edge). The result indicated that the US had the most significant importation risk of 0.63 (95% CI: 0.32, 0.95) during the study period, followed by the United Kingdom (UK) and Canada with a risk of 0.29 (95% CI: 0.10, 0.63) and 0.17 (95% CI: 0.08, 0.32), respectively. Our study demonstrated that the importation risk of mpox from the US and Canada was substantially higher than other regions, which was aligned with the travel history of the first reported case in HK. Our study provided a simplified computational method for estimating the importation risk of mpox virus based on air travel mobility and disease prevalence. Estimating the international importation risk of mpox is essential for appropriately designing and timely adjusting emergency public health strategies and inbound measures.