Impact of airline travel network on the global importation risk of monkeypox, 2022

Background As of 4 September 2020, a total of 53,996 monkeypox cases were confirmed globally. Currently, most monkeypox cases are concentrated in Europe and the Americas, while many countries outside these regions are also continuously observing imported cases. We aimed to estimate the potential global risk of monkeypox importation and consider hypothetical scenarios of travel restrictions by varying passenger volumes via airline travel network. Method Passenger volume data for the airline network, and the time of first confirmed monkeypox case for a total of 1680 airports in 176 countries (and territories) were extracted from publicly available data sources. A survival analysis technique in which the hazard function was a function of effective distance was utilized to estimate the importation risk. Scenarios which selectively reduced the passenger volume from/to countries with detected monkeypox cases and increased/decreased the global passenger volume to the level of 2019 (high volume) or 2021 (low volume) regardless of monkeypox detection were considered for travel restrictions. Results The arrival time ranged from 9 to 48 days since the first case was identified in the UK on 6 May 2022. The estimated risk of importation showed that regardless of the geographic region, most locations will have an intensified importation risk by 31 December 2022. Travel restrictions had a minor impact on the global airline importation risk against monkeypox. Conclusions Instead of preventing the importation of monkeypox cases via airline networks, high risk countries should enhance local capacities for the identification of monkeypox and prepare to carry out contact tracing and isolation.