The UK Health Security Agency (UKHSA) has found “no increasing risk” to human health from the Eurasian H5N1 avian influenza (bird flu) strain, according to its latest investigation.

However, the agency did caution that there has been an increase in confirmed cases of bird flu in the UK and while “there are no indicators of increasing risk to human health” this is a “low confidence assessment”.

According to UKHSA, since the start of the current reporting year (from October 1, 2022) there have been confirmed bird flu cases at 130 premises in England.

“Compared to the previous risk assessment of November 11, 2022, there are a reducing number of infected premises following the introduction of the national housing order for farmed poultry, but still high levels of detections in dead wild birds.

“Influenza A H5N1 is the predominant influenza virus subtype detected in wild birds and farmed flocks in the UK,” the agency added.

Increased levels of bird flu

It has warned that because of increased levels of bird flu there is the risk of an “increased interface between humans and infected birds”.

It said that because of the high number of wild birds and domestic flocks with “influenza A infection”, the likelihood of human exposures to the virus increases if personal protective equipment is not worn.

According to the Department for Environment, Food and Rural Affairs, since October 1, 2022, there have been:

  • 137 cases in England;
  • 14 cases in Scotland;
  • Three cases in Wales;
  • One case in Northern Ireland.

The UKHSA outlined that from October 2022 to December 15, 2022, health protection systems in the UK had recorded 2,085 human exposures – where a person was directly exposed to an infected bird.

However, it said there were no detections of bird flu viruses in humans in the UK during the current reporting year and only one human detection in the UK in the preceding reporting year (October 1, 2021 to September 30, 2022).

The agency detailed that the one human case in 2021, was confirmed in England, in an exposed person who remained asymptomatic throughout.

“This detection was in the context of close and prolonged exposure to infected poultry and contaminated material, without personal protective equipment PPE (personal protective equipment),” it added.

Outside of the UK three human cases of bird flu have been reported internationally by the World Health Organisation (WHO) between December 2021 and December 2022. This included one case from the United States and two cases from Spain.

No human-to-human transmission has been reported.