CHICAGO/LONDON – The United States and Europe are taking steps to acquire or produce an H5N1 avian flu vaccine that could be used to protect at-risk poultry and dairy workers, veterinarians and lab technicians, government officials said, a move that flu experts say could curb the threat of a pandemic.
U.S. officials said last week they were transferring a large amount of a vaccine from CSL Sequilas (CSL.AX) that is highly matched to the current virus into a finished product that could provide 4.8 million doses, and European health authorities told Reuters they were in talks to acquire CSL’s pre-pandemic vaccine.
Canadian health officials said they have met with seasonal influenza vaccine maker GSK (GSK.L) to discuss acquiring and producing pre-pandemic avian flu vaccines once there is spare seasonal flu production capacity.
Scientists say other countries, including Britain, are debating how to proceed with pre-pandemic vaccine development.
The measures come in the wake of the explosive spread of a new strain of avian influenza that emerged in late 2020 and caused unprecedented numbers of deaths among wild and poultry birds and began infecting many mammal species.
In March, U.S. officials reported the first cases of the virus in dairy cows, infecting dozens of cows and two dairy farmers in nine states. The Food and Drug Administration estimates that 20% of the U.S. milk supply shows signs of the virus and that it’s likely to spread further.
Human exposure to the virus in poultry and dairy farming settings may increase the risk that the virus will mutate and gain the ability to easily infect humans.
“We need to do everything we can to prevent this from happening,” said Matthew Miller, co-director of the Canadian Centre for Pandemic Preparedness at McMaster University. “If it spreads between humans, it would be devastating.”
Dr. Angela Rasmussen, a virologist at the University of Saskatchewan, said she is in discussions with U.S. and Canadian officials about using the vaccine to protect workers after the virus spread to new mammal species.
Dawn O’Connell, from the Office of Strategic Preparedness and Response, said the government was “carefully considering” the possibility of vaccinating farmworkers and others who have had close contact with the virus.
The United States has contracted with CSL and GSK to test a pre-pandemic vaccine that is closer to the circulating virus than the older H5N1 vaccine in its stockpile. A Department of Health and Human Services official confirmed that the United States is moving forward with the CSL vaccine.
Wendy Barclay, professor of influenza virology at University College London, who also works on avian flu for the UK Health Security Agency, said discussions about using pre-pandemic vaccines were taking place at government level and among scientists in many places, including in the UK.
If deployed strategically among dairy farmers, health care workers and people who come into close contact with infected animals, “it could stop the virus,” she said, but noted it was not yet clear whether the measure was necessary.
The British government did not comment but said it was monitoring the situation in the US.
In Europe, the European Commission’s health emergency preparedness and response agency is working to jointly procure the CSL Sequilas vaccine as it has the “potential to prevent pandemics” caused by people coming into contact with infected birds or animals, spokesman Stefan De Keersmaeker told Reuters.
A spokesman for CSL, which has pandemic flu vaccine contracts with governments in 30 countries, said the company is in discussions with multiple governments about procuring vaccines from 2022 onwards, and that the U.S. outbreak has accelerated those requests.
Pre-pandemic stockpiling
The United States maintains a stockpile of pre-pandemic vaccine candidates and bulk vaccines against a range of influenza strains and is conducting clinical trials to obtain emergency use authorization or FDA licensure in the event of a pandemic.
Seasonal flu vaccine makers, including Sanofi (SASY.PA) (opens in new tab), may also be asked to shift to producing pandemic flu vaccines.
The U.S. is in talks with mRNA vaccine makers Pfizer (PFE.N) (opens in a new tab) and Moderna (MRNA.O) (opens in a new tab) about a potential pandemic vaccine.
Dr. Richard Webby, a virologist at St. Jude Children’s Research Hospital who studies animal and bird influenza for the World Health Organization, said the situation in dairy cows merits the use of a vaccine.
“If you look at the levels of exposure that some farmers are receiving, you can see that the levels are high,” Webby said.
Nirav Shah, principal deputy director of the US Centers for Disease Control and Prevention (CDC), said decisions about how and when to use the vaccine will depend on evidence of spread, the severity of the disease, infections in people not associated with dairy farms and mutations of the virus.
Ron Fouchier, a Dutch influenza virologist at Erasmus MC in Rotterdam who has been running experiments mapping the changes bird flu needs to make to cause a pandemic, said Europe’s plan is to procure the CSL vaccine for people occupationally exposed to the virus.
He added that once a vaccine becomes available, his lab may be eligible to receive it, “and I would definitely get it.”
