Julie Steenhuisen and Jennifer Rigby
CHICAGO/LONDON (Reuters) – The United States and Europe are taking steps to acquire or produce H5N1 avian flu vaccines that could be used to protect at-risk poultry and dairy workers, veterinarians and laboratory technicians, government officials said, making steps flu experts say could curb the pandemic threat.
U.S. officials last week said they were converting the bulk vaccine from CSL (OTC:) Seqirus, which closely matches the current virus, into off-the-shelf shots that could provide 4.8 million vaccine doses. European health officials told Reuters they are in talks to acquire CSL’s pre-pandemic vaccine.
Canadian health officials said they met with GSK, Canada’s seasonal flu shot maker, to discuss purchasing and producing a vaccine against pre-pandemic avian flu once its seasonal flu production capacity is freed up.
Other countries, including Britain, are discussing how to proceed with pre-pandemic vaccines, scientists say.
These actions follow the explosive spread of a new strain of bird flu that emerged in late 2020 and has caused unprecedented numbers of deaths in wild and domestic birds and has also begun to infect many mammal species.
In March, U.S. officials reported the first outbreak of the virus in dairy cattle, affecting dozens of herds in nine states and two dairy farm workers. The U.S. Food and Drug Administration estimates that 20% of the U.S. milk supply shows signs of the virus, indicating the possibility of wider spread.
Human exposure to the virus in poultry and dairy plants may increase the risk that the virus will mutate and become capable of spreading easily among people.
“All of our efforts should be focused on preventing events like this from happening,” said Matthew Miller, co-director of the Canadian Center for Pandemic Preparedness at McMaster University. “Once we get widespread infection among people, we will have big problems.”
Dr. Angela Rasmussen, a virologist at the University of Saskatchewan, said she has been in discussions with U.S. and Canadian officials about using vaccines to protect workers after the virus spreads to new mammal species.
Dawn O’Connell of the US Strategic Preparedness and Response Administration said the government is “closely looking” at vaccinating farmworkers and others in close contact with the virus.
The U.S. has contracts with CSL and GSK to test pre-pandemic vaccines that more closely match the circulating virus than older H5N1 vaccines in stockpile. The US is moving forward with its rollout of the CSL vaccine, a Department of Health and Human Services spokesperson confirmed.
Discussions about the use of a pre-pandemic vaccine continue at government levels and among scientists in a number of places, including Britain, said Wendy Barclay, head of influenza virology at University College London, who also researches bird flu for the UK’s Health Security Agency.
If it were strategically applied to dairy farmers, health care workers and those in close contact with infected animals, “that would put an end to the virus,” she said, although she said it was unclear whether that step was necessary.
The UK government has not commented on the situation but said it is monitoring the situation in the US.
In Europe, the European Commission’s Health Emergency Preparedness and Response Directorate is working on a joint procurement of the CSL Seqirus vaccine to “potentially prevent a pandemic” caused by people exposed to infected birds and animals, spokesman Stefan De Keersmaeker told Reuters.
A spokeswoman for CSL, which has contracts to supply pandemic flu vaccines with governments in 30 countries, said the company is in talks with several governments to purchase vaccines from 2022. Those requests have accelerated since the outbreak in the United States, she said.
PRE-PANDEMIC STOCK
The United States has a stockpile of pre-pandemic vaccine candidates and a mass vaccine against multiple influenza strains, and is conducting clinical trials to support emergency use authorization or FDA licensure in the event of a pandemic.
Manufacturers of seasonal influenza vaccines, including Sanofi (NASDAQ:), may also be asked to move into the production of pandemic influenza vaccines.
The US is negotiating with mRNA vaccine manufacturers Pfizer (New York Stock Exchange:) and Moderna (NASDAQ:) about potential 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 situation in dairy cattle merits the use of a vaccine.
“When we look at the level of exposure that some of these farmers are exposed to, it is high,” Webby said.
The decision on how and when to use the vaccine will depend on data on increased transmission, the severity of the disease, cases in people not associated with dairy farms, and mutations in the virus, said Nirav, principal deputy director of the US Centers for Disease Control and Prevention. Shah. said.
Dutch influenza virologist Ron Fouchier of Erasmus MC in Rotterdam, who carried out experiments mapping the changes needed for bird flu to cause a pandemic, said Europe’s plan is to purchase the CSL vaccine for people with occupational exposure to the virus.
His lab may well be eligible to participate in the program if a vaccine becomes available, he said, adding, “I would definitely take it.”