Supplementary information for "Simulating the international clade IIb mpox spread patterns in Asia, 2023 and onwards"

This repository contains the supplementary information for the paper "Simulating the international clade IIb mpox spread patterns in Asia, 2023 and onwards". Abstract: Objective: The global mpox outbreak of clade IIb affected many Asian countries in 2023, following a sustained local transmission in Japan. Given the large population sizes and limited vaccine rollout in Asia, the ongoing transmission of mpox in Asia is of global health concern. We aimed to understand and project the international spread patterns of mpox considering the heterogeneity in sexual activity levels among men who have sex with men (MSM). Methods: We constructed a mathematical model incorporating heterogeneous MSM sexual networks and international travel volume, calibrated to incidence data in Japan. We used this model to simulate the pattern of international spread of mpox across 42 Asian countries and territories, assuming Japan as the origin of the spread. Findings: Our simulations highlighted countries and territories at a high risk of mpox introduction, many of which were low- and middle-income countries (LMICs) in South-eastern Asia. The focus of simulated importation risk showed a gradual shift over time from Eastern Asia to South-eastern Asia, and subsequently to Central, Southern and Western Asia, which roughly coincided with the observed spread patterns in 2023–2024. Conclusion: Our multi-country mpox outbreak model can help project the possible trajectory of international spread in Asia. Global cooperation and support to contain mpox outbreaks of clade IIb are warranted, especially for LMICs with an elevated risk of introduction, to minimise the risk of continued circulation in Asia and beyond. Keywords: Mpox, men who have sex with men, Asia, international spread, heavy-tailed distribution, sexual contact