He noted that bird flu can cause “significant mortality” when it infects humans.
Former Centers for Disease Control and Prevention (CDC) Director Robert Redfield predicts the next pandemic may be caused by bird flu, but it’s just a matter of when. Specifically, Redfield spoke on a news program about growing concerns about bird flu as the virus continues to spread among US cattle herds.
“I really think it’s very likely that we will have an avian flu pandemic at some point. It’s not a question of if, but when,” Redfield said.
He also noted that bird flu has a “significantly higher mortality rate” when it infects humans compared with COVID-19.
While the coronavirus has a mortality rate of 0.6%, Redfield said the mortality rate for bird flu is probably “between 25 and 50 percent.”
Last month, U.S. officials reported the third case of bird flu in the country linked to an ongoing outbreak of the virus in dairy cows. Worldwide, doctors have detected 15 human infections with the H5N1 strain of bird flu.
While there is no evidence yet that the virus can spread from person to person, Redfield explained that five amino acids must be present for bird flu to acquire the ability to bind to human receptors and become “human-to-human” like the new coronavirus.
“If the virus attaches to human receptors and gains the ability to transmit from human to human, a pandemic will occur. I think it’s just a matter of time,” he added.
It’s unclear how long it would take for the five amino acids to change, but Redfield said he was concerned because the changes have been detected in cattle herds across the U.S.
“We know exactly which amino acids have to be changed because in 2012, against my advice, the scientists who carried out these experiments published their results, which means the way to make bird flu highly infectious for humans already exists,” he said.
Over the past few years, highly pathogenic avian influenza viruses have infected more than 50 animal species and, since March, have infected dairy cows in the United States.
Unlike in Europe, American farmers are allowed to feed cows ground-up chicken manure, which some scientists say may be a risk factor for bird flu, though the feed industry disputes the claim and U.S. officials believe wild birds are the ones that spread it to cattle.