In 1958, mpox (MPVX) was first discovered when two nonfatal outbreaks of a pox-like disease were reported in colonies of monkeys that were housed for research purposes in Copenhagen, Denmark. It was subsequently named “monkeypox” now known as mpox or MPVX.

The first human case of mpox was reported in 1970 in the Democratic Republic of the Congo (DRC) in a boy aged 9 months who was the only member of his family without a smallpox vaccination. Receiving a previous vaccination against smallpox was estimated to be 85% effective in preventing mpox, although the long-term efficacy of smallpox vaccination was unclear.

Following the first mpox reported in the DRC, mpox subsequently spread to other central and western African countries. Mpox is a zoonotic infection caused by the mpox virus, an orthopoxvirus closely related to the variola virus that causes smallpox.