Estimating the relative importance of epidemiological and behavioural parameters for epidemic mpox transmission: a modelling study

• Published in: BMC medicine Vol. 22; no. 1; pp. 297 - 11
• Main Authors: Chaturvedi, Madhav, Rodiah, Isti, Kretzschmar, Mirjam, Scholz, Stefan, Lange, Berit, Karch, André, Jaeger, Veronika K
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 18-07-2024; BioMed Central; BMC
• Subjects: Age groups; Analysis; Communicable diseases; Contact Tracing; Democratic Republic of the Congo - epidemiology; Disease Outbreaks; Disease transmission; Effectiveness; Epidemics; Epidemiology; Exposure; Female; Global sensitivity analysis; Homosexuality, Male; Humans; Immunity; Infections; Infectious disease modelling; Infectious diseases; Kindergarten; Male; Metapopulations; Modelling; Monkeypox; Mpox; Mpox (monkeypox) - epidemiology; Mpox (monkeypox) - transmission; Outbreaks; Parameter estimation; Parameter identification; Parameter sensitivity; Parameter uncertainty; Pharmaceuticals; Probability; Sensitivity analysis; Sexual Behavior; Sexual transmission; Smallpox; Smallpox vaccine; Stochasticity; Vaccination; Vaccines; Democratic Republic of the Congo; Germany; Infectious disease modelling; Global sensitivity analysis; Mpox
• ISSN: 1741-7015; 1741-7015
• DOI: 10.1186/s12916-024-03515-8

Many European countries experienced outbreaks of mpox in 2022, and there was an mpox outbreak in 2023 in the Democratic Republic of Congo. There were many apparent differences between these outbreaks and previous outbreaks of mpox; the recent outbreaks were observed in men who have sex with men after sexual encounters at common events, whereas earlier outbreaks were observed in a wider population with no identifiable link to sexual contacts. These apparent differences meant that data from previous outbreaks could not reliably be used to parametrise infectious disease models during the 2022 and 2023 mpox outbreaks, and modelling efforts were hampered by uncertainty around key transmission and immunity parameters.
We developed a stochastic, discrete-time metapopulation model for mpox that allowed for sexual and non-sexual transmission and the implementation of non-pharmaceutical interventions, specifically contact tracing and pre- and post-exposure vaccinations. We calibrated the model to case data from Berlin and used Sobol sensitivity analysis to identify parameters that mpox transmission is especially sensitive to. We also briefly analysed the sensitivity of the effectiveness of non-pharmaceutical interventions to various efficacy parameters.
We found that variance in the transmission probabilities due to both sexual and non-sexual transmission had a large effect on mpox transmission in the model, as did the level of immunity to mpox conferred by a previous smallpox vaccination. Furthermore, variance in the number of pre-exposure vaccinations offered was the dominant contributor to variance in mpox dynamics in men who have sex with men. If pre-exposure vaccinations were not available, both the accuracy and timeliness of contact tracing had a large impact on mpox transmission in the model.
Our results are valuable for guiding epidemiological studies for parameter ascertainment and identifying key factors for success of non-pharmaceutical interventions.