Mpox, previously known as monkeypox, is a viral illness caused by the monkeypox virus (MPXV).1 It causes a painful rash, enlarged lymph nodes, fever, headache, muscle ache, back pain and low energy or feeling sick. In most cases, the symptoms of mpox go away within a few weeks with supportive care. In some people, the illness can be severe or lead to complications and even death.