On 6 January 2022, the International Health Regulations (IHR) Focal Point of the United Kingdom of Great Britain and Northern Ireland notified WHO of the detection of a laboratory confirmed human case of avian influenza A(H5) from South West England.

The case lived with a large number of domestically kept birds which had onset of illness on 18 December 2021, and subsequently tested positive with Highly Pathogenic Avian Influenza (HPAI) A(H5N1) by the United Kingdom National Reference Laboratory at the Animal and Plant Health Agency (APHA) Weybridge laboratory.  As part of routine follow up of exposed persons to avian influenza cases, an upper respiratory swab was taken from the case on 24 December 2021 which tested positive for influenza A with subtyping H5. Further characterization of the virus is ongoing. This result was reproduced on two successive upper respiratory swabs collected during the following days. The case has remained clinically asymptomatic and is now considered to not be infectious.

Following successful virus isolation from samples collected from birds on the infected premises, APHA analyzed full genome sequence data for the HPAI A(H5N1) virus present in these birds. Genomic analysis demonstrated that the sequence generated contained no strong correlates for specific increased affinity for humans.

Public health response

All contacts have been identified and managed according to the national public health protocols. None of the contacts have reported symptoms and no evidence of secondary transmission has been identified to date. 

The infected premises were visited by APHA personnel who completed culling of all the birds. Several measures including complete decontamination and cleaning of the outside of the property have been completed.

A three-kilometer captive bird (monitoring) controlled zone was declared by the Department for Environment, Food and Rural Affairs around the infected premises. The zone will remain in place for at least 21 days following the completion of preliminary cleansing and disinfection and will not be lifted until surveillance activities including clinical inspections of all commercial premises in the zone have been undertaken.

WHO risk assessment

Since 2003, a total of 863 cases and 455 deaths of influenza A(H5N1) human infection have been reported worldwide, including this case in the United Kingdom. The most recently reported case in humans prior to the current case, was in October 2020 in Lao People's Democratic Republic in a one-year-old female who had exposure to backyard poultry (for more details, please see the Disease Outbreak News published on 17 November 2020).  

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