US and some EU states consider building stocks of bird flu vaccines for at-risk dairy and poultry workers

Canadian health officials said they had met with GSK, maker of Canada’s seasonal flu shots, to discuss acquiring and manufacturing a pre-pandemic bird flu vaccine once its seasonal flu production capacity is freed up.

Other countries, including the UK, are discussing how to proceed on pre-pandemic vaccines, scientists said.

The actions follow the explosive spread of a new strain of bird flu that emerged in late 2020 and has caused unprecedented numbers of deaths among wild birds and domestic poultry and has begun infecting many mammal species.

In March, US officials reported the first outbreak of the virus in dairy cattle, which has infected dozens of herds in nine states and two dairy workers. 

The US Food and Drug Administration has estimated 20% of the US milk supply shows signs of the virus, indicating a wider spread is likely.

Human exposures to the virus in poultry and dairy operations could increase the risk the virus will mutate and gain the ability to spread easily in people.

“All of our efforts need to be focused on preventing those events from happening,” said Matthew Miller, co-director of the Canadian Pandemic Preparedness Hub at McMaster University. 

Once we have widespread infections of humans, we’re in big trouble.

Dr Angela Rasmussen, a virologist at the University of Saskatchewan, said she had been in discussions with US and Canadian officials about using vaccines to protect workers following the virus’s spread into new mammal species.

The US has contracts with CSL and GSK to test pre-pandemic vaccines that more closely match the circulating virus than older H5N1 vaccines in the stockpile. The US is moving forward with the CSL vaccine, a Department of Health and Human Services official confirmed.

Discussions about pre-pandemic vaccine use are going on at government levels and among scientists in a number of places, including in the UK, said Wendy Barclay, chair in influenza virology at University College London, who also researches avian flu for the UK Health Security Agency.

If deployed strategically to dairy farmers, healthcare workers and those in close contact with infected animals, “it would put a pin in the virus,” she said, although she said it was not clear if this step was necessary yet.

In Europe, the European Commission’s Health Emergency Preparedness and Response Authority is working on a joint procurement of CSL Seqirus’s vaccine to “potentially prevent a pandemic” sparked by individuals exposed to infected birds and animals, spokesman Stefan De Keersmaecker told Reuters.

A spokeswoman for CSL, which has contracts for pandemic influenza vaccines with 30 governments, said the company has been in talks with several governments about procuring vaccines since 2022. Those requests have accelerated with the US outbreak, she said.

– Reuters