An ongoing outbreak of monkeypox that started in the United Kingdom began on 29 April 2022 with the presentation of monkeypox symptoms in a British resident who had travelled to Nigeria, where the disease is endemic. The individual subsequently returned to the United Kingdom on 4 May, importing the index case of the outbreak into the country.

The source of several of the cases of monkeypox in the United Kingdom is unknown; however, it appears that community transmission is taking place in the London area as of mid-May. Cases of the virus have also been reported in North East England as well as outside the UK: one in Portugal, two in the United States and five in Canada as of 18 May. While the disease appears to be sexually transmissible there is yet further research needed to confirm that.

It is the sudden and rapid spread of this disease out of its African breeding ground that is cause for concern. On May 18 in Portugal, 14 cases of Monkeypox were reported by health authorities out of total of 20 suspected cases, with 2 samples still awaiting for test results. In Spain, there are 7 confirmed cases as of May 18. On the same day, the United States confirmed its first 2022 case of Monkeypox and Canada reported 13 suspected cases.

The symptoms of monkeypox are similar to but milder than smallpox. Infected people develop flu-like symptoms — fever, body aches, chills — but also swollen lymph nodes. With one to three days of the onset of fever, a distinctive rash appears, often starting on the face.