DOI: 10.2807/1560-7917.es.2026.31.30.2600604 ISSN: 1560-7917
A rapidly developing outbreak of clade Ib mpox among gay, bisexual and other men who have sex with men associated with severe proctitis, Northern Ireland, June 2026
Abbie Harrison, Catherine Burns, Corey Magee, Monica Sloan, Joy Murphy, Laura McCartney, Maeve Middleton, Emma McCarty, Eoin Walker, John White, Melissa Perry, Nuala Cavanagh, Bill Gibson, Stephen Megarity, Kathy Li, Susan Feeney, Declan Bradley, Peter Naughton, Rachel CoyleWe describe a rapidly expanding clade Ib mpox outbreak among gay, bisexual and other men who have sex with men in Northern Ireland. Following 12 months with no detected mpox cases, 22 confirmed cases were notified between 6 and 30 June 2026. Cases had a median age of 41 years; 19 had not travelled outside the United Kingdom or Ireland in the 21 days before symptom onset. The outbreak is characterised by severe anorectal disease and presentation to non-sexual health settings, including secondary care.