Rising Monkeypox Cases and Decreased Smallpox Immunity Raise Concerns of Potential Pandemic

Monkeypox can spread rapidly among humans. Over 10,000 new Monkeypox virus(MPV) cases were reported between May 4 and July 12, 2022. It is transmitted through contact with infected animals, respiratory droplets, and shared items. Symptoms are similar to smallpox but milder. Smallpox is caused by variola virus (VAV). The halt in smallpox vaccinations has left 70% of the world unvaccinated against related viruses.  Preliminary genetic data shows differences between VAV and MPV. Though their core genomic regions are nearly identical, the end genomic regions exhibit significant differences in factors like virulence and host domain. Immunity against VAV also protects against MPV; the smallpox vaccine offers strong resistance to MPV in around 85% of individuals. However, immunity against smallpox has decreased over the years, leading to increased susceptibility to monkeypox in unvaccinated adults aged 21 to 40, and indicating a risk of MPV transmission and higher illness prevalence in older populations. The increase in monkeypox cases, changing transmission patterns, the decreased immunity against smallpox, and the potential for bioterrorism are all reasons to monitor the situation closely and implement measures to contain these viruses.