June 3, 2024

 

US, Europe consider vaccinating workers exposed to H5N1 bird flu

Efforts to secure H5N1 bird flu vaccines are underway in the US and Europe, targeting protection for at-risk poultry and dairy workers, veterinarians, and lab technicians, Reuters reported.

 

Government officials and influenza experts said these steps could help prevent a potential pandemic.

 

Last week, US officials announced the transition of bulk vaccine from CSL Seqirus into finished shots, capable of yielding 4.8 million doses. European health officials disclosed ongoing discussions to acquire CSL's pre-pandemic vaccine. Meanwhile, Canadian health officials have engaged with GSK, the manufacturer of Canada's seasonal flu shots, to explore acquiring and producing a pre-pandemic bird flu vaccine once seasonal flu production is complete.

 

The UK and other countries are also deliberating on pre-pandemic vaccine strategies, according to scientists.

 

The moves follow the spread of a new bird flu strain that emerged in late 2020, causing unprecedented deaths among wild birds and domestic poultry, and recently infecting various mammal species. In March, US officials reported the first outbreak in dairy cattle, affecting herds in nine states and infecting two dairy workers. The US Food and Drug Administration estimates that 20% of the U.S. milk supply shows signs of the virus, suggesting a broader spread.

 

Experts warn that human exposure to the virus in poultry and dairy operations could increase the risk of the virus mutating and becoming easily transmissible among 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.

 

Dr Angela Rasmussen, a virologist at the University of Saskatchewan, confirmed discussions with US and Canadian officials on using vaccines to protect workers following the virus's spread to new mammal species. Dawn O'Connell of the US Administration for Strategic Preparedness and Response stated that the government is considering vaccinating farm workers and others in close contact with the virus.

 

The US has existing contracts with CSL and GSK to test pre-pandemic vaccines that match the current virus more closely than older stockpiled H5N1 vaccines. The US is advancing with the CSL vaccine, according to a Department of Health and Human Services official.

 

Wendy Barclay, chair in influenza virology at University College London, noted ongoing discussions among scientists and government officials in the UK about pre-pandemic vaccine use. If strategically deployed to dairy farmers, healthcare workers, and others in close contact with infected animals, "it would put a pin in the virus," she said, although the necessity of this step remains under evaluation.

 

In Europe, the European Commission's Health Emergency Preparedness and Response Authority is pursuing joint procurement of CSL Seqirus's vaccine to prevent a potential pandemic from exposure to infected birds and animals, according to spokesman Stefan De Keersmaecker.

 

A spokeswoman for CSL revealed the company has been in talks with multiple governments about procuring vaccines since 2022, with increased urgency following the US outbreak.

 

The US maintains a stockpile of pre-pandemic vaccine candidates and bulk vaccines for various influenza strains, conducting clinical trials to support emergency use authorization or FDA licensing in a pandemic scenario. Seasonal flu vaccine manufacturers, including Sanofi, might also be called upon to produce pandemic flu vaccines. Additionally, the US is in discussions with mRNA vaccine makers Pfizer and Moderna about potential pandemic vaccines.

 

Dr Richard Webby, a virologist at St. Jude Children's Research Hospital, emphasized the high exposure levels of farmers, suggesting the situation in dairy cattle merits vaccine use. Decisions on vaccine deployment will depend on evidence of increased transmission, disease severity, cases in people without dairy farm links, and virus mutations, according to US Centres for Disease Control and Prevention Principal Deputy Director Nirav Shah.

 

Dutch flu virologist Ron Fouchier of Erasmus MC in Rotterdam, who has studied bird flu's pandemic potential, indicated that Europe's plan includes procuring the CSL vaccine for those occupationally exposed. He expressed willingness to receive the vaccine if available.

 

-      Reuters