Adaptive Changes in Sexual Behavior in the High-Risk Population in Response to Human Monkeypox Transmission in Canada Can Control the Outbreak: Insights from a Two-Group, Two-Route Epidemic Model

Abstract

Monkeypox, a zoonotic disease caused by the monkeypox virus, is emerging as a potential sexually transmitted disease (STD). Starting from the end of April 2022, a monkeypox outbreak is ongoing. Canada has become one of the most affected countries in the WHO Region of the Americas. Mathematical modeling plays a crucial role in monitoring, controlling, and forecasting infectious disease outbreaks, including those generated by STDs. Here, we devised a deterministic compartmental susceptibleexposed-infectious-quarantined-recovered/removed (SEIQR) model incorporating sexual behavior dynamics and stratifying the population into high- and low-risk groups. We explore and compare different intervention strategies targeting the high-risk population: i) a scenario of control strategies, implementing a policy geared towards use of condoms and/or sexual abstinence (robust control strategy); ii) a scenario of control strategies with risk compensation behavior change, assuming a compensation through conducting more sexual encounters for adopting protective behavioral strategies (risk compensation strategy); and, iii) a scenario of control strategies with behavior change in response to the doubling rate (adaptive control strategy). We estimated that the basic reproduction number of monkeypox is 1.464, 0.0066, and 1.461 in the high-risk, low-risk, and total populations, respectively, implying that members of the high-risk group are the major drivers of monkeypox spread in Canada, as confirmed by the sensitivity analysis. In the first scenario, policies of imposing only condom use or only sexual abstinence need to achieve a minimum compliance rate of more than 35% to successfully stop further monkeypox transmission, while a combination of both can curb the disease spread if there is 10% compliance to abstinence and 25% to condom use, suggesting a combination of control measures is the most efficient way to contain the outbreak. In the second scenario, the only effective option to control monkeypox transmission is to impose sexual abstinence by at least 35%. In the third scenario, the smaller the critical case doubling rate is, the earlier individuals in the high-risk group proactively reduce their daily sexual contact numbers as protective measures. We also found that adaptive control is more effective compared to the robust control where the daily sexual contact number is reduced proportionally and remains as a constant thereafter. In conclusion, the adaptive behavior changes among the high-risk group shorten the time to epidemic peak, lower the epidemic peak size, and facilitate the attenuation of the disease, playing a key role in controlling the current outbreak of monkeypox in Canada.

Note:
Funding Information: This research is funded by Canada’s International Development Research Centre (IDRC) and the Swedish International Development Cooperation Agency (SIDA) (Grant No. 109559- 001). NLB and JDK acknowledge support from IDRC (Grant No. 109981). JDK acknowl- edges support from New Frontier in Research Fund-Exploratory (Grant No. NFRFE-2021- 00879) and NSERC Discovery Grant (Grant No. RGPIN-2022-04559). XW acknowledges support from the NSERC of Canada (RGPIN-2020-06825 and DGECR-2020-00369).

Conflict of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.