World Health Organization Worried About Potential Spread of Bird Flu to Humans
H5N1 avian flu has recently infected cows and goats in the United States.
There’s a risk avian influenza, after spreading to several new mammal species, will begin to infect more humans, the chief scientist of the World Health Organization (WHO) said on April 18.
Highly pathogenic avian influenza A, or H5N1, has recently infected cows and goats in the United States, after spreading among chickens for years.
H5N1 has kept circulating to new species and has “become a global zoonotic animal pandemic,” Jeremy Farrar, the WHO’s chief scientist, told reporters in Geneva.
“The great concern, of course, is that in doing so, and infecting ducks and chickens but now increasingly mammals, that that virus now evolves and develops the ability to infect humans, and then critically the ability to go from human to human,” he added.
The influenza, commonly known as bird flu, has infected cattle in eight states, most recently in South Dakota. One person in Texas has been confirmed to have contracted the illness. Sequencing of a sample collected from that patient showed the virus had one change from earlier animal sequencing, and the change has been linked with making the virus more likely to infect animals, the U.S. Centers for Disease Control and Prevention (CDC) said this month.
However, the change has been detected before, with no evidence the influenza has then spread onward among people, the agency noted. “Further, there are no markers known to be associated with influenza antiviral resistance found in the virus sequences from the patient’s specimen and the virus is very closely related to two existing HPAI A(H5N1) candidate vaccine viruses that are already available to manufacturers, and which could be used to make vaccine if needed.”
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Since 2003, 889 humans have had confirmed infections, and 463 of those infected died, according to the WHO.
“We know that in the rare cases … so far in humans, the mortality rate is extremely high,” Mr. Farrar said. “So to me, this is a major concern.”
Crucial questions to answer include how the influenza is transmitted to cows and whether any additional people have contracted the flu from cattle.
Some previous influenza strains have adapted to start spreading among humans, including H1N1.
H5N1 viruses “have a distinct capacity to, in many cases infect several different species, but especially several different species of mammals including humans. And it has the capacity to not only infect and adapt but also to cause severe disease,” Marcela Uhart, a veterinarian who directs the Latin America Program at the University of California Davis’ school of veterinary medicine, said in a recent webinar. “So this is why we must [be] and we are on alert because of the continuous expansion and transmission of this H5N1, especially as it moves more and more and more into marine mammals and other types of mammals.”
Ready to Respond
If the flu starts transmitting between humans, then health officials must ensure they are “in a position to immediately respond with access, equitably, to vaccines, therapeutics, and diagnostics,” Mr. Farrar said.
The CDC has said that the strain currently circulating is closely related to several vaccine candidates that are available for production.
Dr. Mandy Cohen, the CDC’s director, told Politico that if certain developments take place, such as human-to-human transmission, then U.S. authorities would step up the response to the next level.
The CDC declined a request for comment but a spokesperson for the U.S. Food and Drug Administration said that the agency has already approved three H5N1 vaccines, from Sanofi Pasteur, the ID Biomedical Corporation of Quebec, and Seqirus, and is ready to act if needed.
“If it is determined that the U.S. population needs to be vaccinated to prevent H5N1 influenza, then the anticipated regulatory pathway would likely be for those manufacturers who have an approved H5N1 influenza vaccine to submit a manufacturing strain change supplement to FDA, as occurs for the seasonal influenza vaccines,” the spokesperson told The Epoch Times in an email.
Even with the prior approval, immunogenicity data from clinical trials with vaccines with updated strains would be needed, according to FDA guidance.
Dawn O’Connell, the assistant secretary for preparedness and response, told Politico that hundreds of thousands of doses would be ready to be administered within weeks if the FDA cleared the updated vaccines.
A spokesman for the Administration for Strategic Preparedness and Response, which Ms. O’Connell leads, told The Epoch Times that agencies across the government are monitoring the bird flu situation.
The U.S. Department of Agriculture said this week that it is looking into developing a poultry vaccine against H5N1 “to stock and use in an emergency.”
