US, European countries consider vaccinating workers exposed to bird flu

Chicago/London: The United States and Europe are taking steps to acquire or manufacture H5N1 avian influenza vaccines that could be used to protect at-risk poultry and dairy workers, veterinarians and food technicians. laboratory, government officials said. threat of a pandemic.

U.S. officials said last week they were moving a bulk vaccine from CSL Seqirus, which closely matches the current virus, into finished shots that could provide 4.8 million vaccine doses. European health officials told Reuters they were in talks to acquire CSL’s pre-pandemic vaccine.

Canadian health officials said they met with GSK, maker of Canada’s seasonal flu vaccines, to discuss acquiring and manufacturing a pre-pandemic avian flu vaccine once its production capacity against seasonal flu will be released.

Other countries, including the United Kingdom, are discussing how to proceed with pre-pandemic vaccines, scientists said.

These actions follow the explosive spread of a new strain of avian flu that emerged in late 2020 and has caused an unprecedented number of deaths among wild birds and domestic poultry and has begun to infect many species of mammals.

In March, U.S. authorities reported the first outbreak of the virus in dairy cattle, which infected dozens of herds in nine states and two dairy workers. The U.S. Food and Drug Administration has estimated that 20 percent of the U.S. milk supply shows signs of the virus, indicating that wider spread is likely.

Human exposure to the virus on poultry and dairy farms could increase the risk that the virus will mutate and gain the ability to spread easily among humans.

“All of our efforts must be focused on preventing these events,” said Matthew Miller, co-director of the Canadian Center for Pandemic Preparedness at McMaster University. “Once we have widespread infections in humans, we are in big trouble. »

Dr. Angela Rasmussen, a virologist at the University of Saskatchewan, said she has had discussions with U.S. and Canadian officials about using vaccines to protect workers following the spread of the virus to new species of mammals.

Dawn O’Connell of the US Strategic Preparedness and Response Administration said the government was “closely studying” the possibility of vaccinating farmworkers and others in close contact with the virus.

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

Discussions about pre-pandemic use of a vaccine are underway at the government level and among scientists in several places, including the United Kingdom, said Wendy Barclay, chair of influenza virology at University College. of London, who also studies avian flu for the British Health Security Agency.

If deployed strategically to dairy farmers, health care workers and people in close contact with infected animals, “it would pin down the virus,” she said, although she said that It was not yet clear whether this measure was necessary.

The British government did not comment but said it was monitoring the situation in the United States.

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

A spokeswoman for CSL, which has contracts for pandemic flu vaccines with 30 governments, said the company has been in talks with several governments about purchasing vaccines since 2022. Those requests have accelerated with the epidemic in the United States, she said.

The United States maintains a stockpile of pre-pandemic vaccine candidates and bulk vaccines against a wide range of influenza strains and is conducting clinical trials to support an emergency use authorization or FDA pandemic license.

Manufacturers of seasonal flu vaccines, including Sanofi, may also be asked to turn to producing pandemic flu vaccines.

The United States is in talks with mRNA vaccine makers Pfizer and Moderna about possible pandemic vaccines.

Dr. Richard Webby, a virologist at St. Jude Children’s Research Hospital who studies influenza in animals and birds for the World Health Organization, said the dairy cattle situation merits the use of a vaccine.

“If we look at the exposure levels that some of these farmers are exposed to, they are high,” Webby said.

The decision on how and when to use the vaccine will depend on evidence of increased transmission, disease severity, cases in people unrelated to a dairy farm and mutations of the virus, said Nirav Shah, senior deputy director from the United States Centers for Disease Control and Prevention. said.

Dutch flu virologist Ron Fouchier of Erasmus MC in Rotterdam, who has carried out experiments mapping the changes needed for bird flu to trigger a pandemic, said the European plan was to provide the CSL vaccine to people professionally exposed to the virus.

His lab may well be eligible if a vaccine becomes available, he said, adding, “I would definitely take it.”