What is Mpox?
Mpox (formerly known as monkeypox) is a rare disease caused by infection with the mpox virus. Monkeypox virus is part of the same family of viruses as variola virus, the virus that causes smallpox. Mpox symptoms are similar to smallpox symptoms, but milder, and mpox is rarely fatal. Mpox is not related to chickenpox.
Mpox was discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research. Despite being named “Monkeypox virus,” the source of the disease remains unknown. However, African rodents and non-human primates (like monkeys) might harbor the virus and infect people.
The first human case of mpox was recorded in 1970. Before the 2022 outbreak, mpox had been reported in people in several central and western African countries. Previously, almost all mpox cases in people outside of Africa were linked to international travel to countries where the disease commonly occurs or through imported animals. These cases occurred on multiple continents.
There are two types of mpox virus: Clade I and Clade II. The Clade I type of mpox virus has a fatality rate around 10%.
Infections in the 2022–2023 outbreak are from Clade II, or more specifically, Clade IIb.
Infections with Clade IIb are rarely fatal. More than 99% of people who get this form of the disease are likely to survive. However, people with severely weakened immune systems, children younger than 1 year of age, people with a history of eczema, and people who are pregnant or breastfeeding may be more likely to get seriously ill or die.