March 29, 2023

expert reaction to latest technical report on avian flu

The UK Health Security Agency (UKHSA) has published* a new technical report on the risk to human health from avian flu.

Prof Ian Jones, Virologist at the University of Reading, said:

“The latest technical briefing concludes that the risk of human infection by the current H5N1 virus has not increased. This is because, although there is still virus around, there is no evidence of the virus being any more adapted to human transmission now than was observed previously. Consistent with this, the number of avian flu infections in people remains low, with no indication of an upward trend. 

“The illustrative scenarios, while plausible, are still very speculative. Their usefulness is that they provide a chalking out which relates to planning, but as the actual numbers for R and the level of severity are not known they are no more than thinking aloud at the present time.  

“The biggest limitation for this work is that any new flu pandemic, as for those to date, is likely to initiate outside the UK, independent of the surveillance and considerations that are undertaken here.”

Prof James Wood, Head of Department of Veterinary Medicine, University of Cambridge, said:

“UKHSA rates the risk level to be generally the same as in the last quarter, although the rate of incursions of H5N1 virus into farmed poultry has decreased substantially, along with lower levels of exposure in humans. This is as expected for this time of year. The conclusions are limited by the low rates of surveillance, especially in wild birds where surveillance is particularly challenging. Some limited numbers of spillovers of infection from birds to wild mammals have been detected in the UK, but there is greater concern that these could be significant where, for example, mink are still farmed. Some mammalian adaptations of the virus have been found in these mammals, but no clear evidence of mammal to mammal transmission in the UK. Maintaining animal surveillance and, if possible, increasing wild bird surveillance remains an important priority to allow early detection and increased preventive measures.”

* Avian influenza (influenza A H5N1): technical briefings https://www.gov.uk/government/publications/avian-influenza-influenza-a-h5n1-technical-briefings/investigation-into-the-risk-to-human-health-of-avian-influenza-influenza-a-h5n1-in-england-technical-briefing-3

Declared interests

Prof Ian Jones: No conflicts

Prof James Wood: “I have current BBSRC funding to conduct research in avian influenza, focused on farm biosecurity.”