Preventing Disease Emergence Following Eradication: Application to Mpox

Area of Science:

• Epidemiology
• Mathematical Modeling
• Virology

Background:

• Declining population immunity to poxviruses post-smallpox eradication.
• Reduced vaccinia immunization impacts immunity against related viruses like mpox.
• Increased mpox spillovers and human-to-human transmission are observed.

Purpose of the Study:

• To explore factors influencing mpox evolutionary emergence.
• To model the transition to sustained human-to-human transmission.
• To assess the impact of transmissibility versus spillover events on mpox emergence.

Main Methods:

• Utilized simple mathematical models.
• Simulated evolutionary dynamics of mpox.
• Analyzed factors affecting transmissibility and spillover.

Main Results:

• Increased human-to-human transmissibility significantly elevates mpox emergence probability.
• Zoonotic spillover frequency has a lesser impact on emergence compared to transmissibility.
• Mpox requires a reproductive number slightly above one to become endemic, with potential for further adaptation.

Conclusions:

• Enhanced human-to-human transmissibility is the primary driver for mpox evolutionary emergence.
• Post-emergence control requires substantially higher vaccination levels than pre-emergence prevention.
• Mathematical modeling provides insights into mpox pandemic potential and control strategies.