Mpox global health emergency: Insights into the virus, immune responses, and advancements in vaccines PART I: Insights into the virus and immune responses.

Mpox, the zoonotic disease caused by Monkeypox virus (MPXV), is currently a global health emergency. This review (Part I) aims to provide insights into the virus life cycle, epidemiology, host immune responses, and immune evasion mechanisms. Mpox symptoms is similar to smallpox but with lower mortality rates and lower transmissibility. In the past, the virus has been endemic in Central (Clade I) and West (Clade II) African countries. The first outbreak in outside Africa is reported in the United States in 2003. A multi-country outbreak across all continents occurred in 2022, predominantly driven by Clade II. Recently, the emergence of Clade Ib with sustained person-to-person transmission characteristic in the 2023-2024 outbreaks has raised significant public health concerns. Its apparent capacity for rapid spread and potential for causing severe disease highlight the need for enhanced surveillance, especially in regions not traditionally affected by Mpox. Immune responses induced by MPXV infection in humans and animal models provide the insights into the key step in which the host immune response recognizes and responds to the infection. The sophisticated immune evasion strategy by MPXV at both innate and adaptive arms also emerges that are useful for vaccine-based control measures. Taken together, understanding MPXV life cycle, epidemiology and immune response will facilitate better control, limit viral spread, and provide important insights for vaccine development.