Speaker
Description
The WHO declared mpox a public health emergency of international concern on July 23, 2022. It is still unclear to what extent international travel contributed to the sustained spread of mpox and the degree to which national vaccination campaigns were responsible for controlling the epidemic. We employ phylogeographic and phylodynamic models to jointly analyze mpox genomes from viruses sampled between March 2022 and January 2023 from five global regions together with air traffic and epidemiological data to analyze the global and regional spread of mpox.
We find extensive community transmission prior to detection by public health surveillance. Through the development of novel methods to estimate mpox transmission intensity that account for changes in case-detection, we challenge prior estimates of mpox transmission rate and allow for more accurate evaluation of the impact of population-wide interventions. Our analyses show that after initial seeding, viral introductions played a negligible role in prolonging regional epidemics. As such, we estimate that a complete travel ban after initial seeding would have only prevented less than 10% of all cases. Finally, in contrast to widespread belief, we show that the North American epidemic began to decline before even 10% of the population at high risk for mpox in the US had any vaccine-induced immunity, suggesting that behavioral modifications among men who have sex with men, not vaccination campaigns, had a dominant impact in stopping early transmission.
Despite continued global efforts in improving disease surveillance, we show a high degree of underdetection in the early stages of the epidemic which contributed to rapid community spread. Given that cases quickly declined after detection most likely due to community behavioral modifications and not medical countermeasures, our findings highlight the importance of broader routine specimen screening surveillance and of joint integration of genomic and epidemiological information for early outbreak control.
