There’s a risk that 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, Switzerland.
“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 said.
Avian 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 that 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 Centers for Disease Control and Prevention (CDC) stated this month.
However, the change has been detected before, with no evidence that the influenza has then spread onward among people, according to the agency.
“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,” the CDC stated.
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.
Ready to Respond
If the flu starts transmitting between humans, then health officials must ensure that they are “in a position to immediately respond with access, equitably, to vaccines, therapeutics, and diagnostics,” according to Mr. Farrar.The CDC has said that the strain currently circulating is closely related to several vaccine candidates that are available for production.
Dr. Mandy Cohen, director of the CDC, 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 Food and Drug Administration (FDA) said 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, 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 program] works closely with industry partners to make and test updated vaccines that match new strains of influenza viruses with pandemic potential as they emerge, while at the same time, supporting manufacturing capacity to allow for large-scale vaccine production if needed,” he said. “Vaccine candidates being developed and tested under this preparedness program, in close coordination with manufacturers are expected to match the current strain.”
The Department of Agriculture stated last week that it is looking into developing a poultry vaccine against H5N1 “to stock and use in an emergency.”
