On May 30, 2023, the United Kingdom of Great Britain and Northern Ireland reported to the World Health Organization (WHO) the detection of avian influenza A(H5) virus in a poultry worker at a farm in England where poultry was infected with high pathogenicity avian influenza (HPAI) A(H5N1) viruses. Another detection was reported in a second individual performing culling operations on the farm.

Both detections were later confirmed by additional testing as A(H5N1). Both cases were asymptomatic and detected as part of an ongoing enhanced surveillance study of asymptomatic workers exposed to poultry infected with avian influenza.