[BMJ, 14 March 2023]

Global reports of highly pathogenic avian influenza A(H5N1) in birds are increasing, with cases reported from every region except Australasia and Antarctica since 2020.1 The global spread of these avian influenza outbreaks is unprecedented, exacting large economic losses to poultry industries and tourism, and posing a substantial threat to global health security and animal ecology.

In Europe, 2520 H5N1 outbreaks were reported in poultry between October 2021 and September 2022, and the virus was also detected in 3867 dead wild birds.2 The US reported 131 mammalian H5N1 infections among bears, foxes, raccoons, skunks, and seals between May 2022 and February 2023.3 In October 2022, an H5N1 outbreak among Spanish farmed minks was reported for the first time,4 triggering concerns that the virus might soon become transmissible between humans (mink are physiologically similar to ferrets, the animal model used to study transmissibility of influenza viruses among humans).5

On 24 February 2023, an 11 year old girl died from an H5N1 avian flu infection in Cambodia and…