Is U.S. Prepared for Bird Flu’s Spread in Humans? One Expert Has Concerns

THURSDAY, Feb. 6, 2025 (HealthDay News) — When it comes to the potential of H5N1 avian flu, otherwise known as bird flu, picking up mutations that might lead to human-to-human spread, that “train has already left the station,” warns one infectious disease expert.

If and when bird flu — already widespread in cattle, cats and other mammals — gains the ability to transmit between people, the best Americans can hope for is to “control the speed of the train” with vaccines, masks and treatment, said Dr. Peter Chin-Hong. He”s a professor of medicine at the University of San Francisco.

Speaking with HealthDay, Chin-Hong stressed that both rapid surveillance and reporting on any new cases of H5N1 that arise are crucial. So the recent silencing of communications from the U.S. Centers for Disease Control and Prevention (CDC) by the Trump administration is worrisome.

“It”s not that people won”t get the information eventually if it”s serious, it”s the rapidity of information that I”m worried about,” Chin-Hong said.

He compared the recent CDC gag order to a dysfunctional smoke alarm.

“You hope the fire isn”t going to come, but if it comes, there will be a delay before you feel it,” Chin-Hong said. “Time means lives when we”re talking about infectious diseases that really don”t know any borders.”

As the UCSF expert explained, the current strain of bird flu has been circulating through avian species for about 30 years. It has only occasionally infected people — usually those who”ve had extended close contact with birds, such as poultry farm workers.

However, viruses are built to mutate and find new hosts.

That”s what”s been happening with alarming rapidity in recent years, with more cases of mammals — such as seals, cattle, cats, dogs and pigs — coming down with bird flu.

Just one mutation

Over the past year, especially, there”s been an uptick of cases among American people, including the recent death of an already frail patient in Louisiana.

In most human cases, H5N1 was thought to have been contracted from close contact with an infected animal.

Unfortunately, human-to-human transmission may only require a few new genetic tweaks by the virus, Chin-Hong warned.

“I think the length of the road before [we see] a mutation that allows easier entry into our lungs is much shorter than people think,” he said.

One recent study “looked at the amount of mutations needed before that can occur, and it was very, very short, just one mutation,” Chin-Hong noted. “[That] doesn”t mean that this mutation will be picked up, but what it means to me is that it”s not that far away.”

He explained that H5N1 can also interact with “regular” seasonal flu viruses.

“We have a lot of influenza going around and influenza is engineered to really swap genes with each other and they can pick up tricks,” Chin-Hong told HealthDay. “And some of those tricks include getting the combination to enter our bodies, which it is not so great at doing right now.”