At the start of 2025, health officials in Louisiana reported the first U.S. bird flu death and experts questioned whether highly pathogenic avian influenza A (H5N1) could lead to the next pandemic. A second death occurred in November. Here’s a look at what happened with bird flu during the rest of the year.
News that a person had died after being hospitalized with severe respiratory symptoms from H5N1 bird flu was alarming, though the CDC stated at the time in January that it was not entirely unexpected given the “known potential” of the virus “to cause severe illness and death,” AP reported. The agency also noted that the risk to the general public remained low.
The individual who died was older than 65, had underlying health conditions, and had been in contact with sick and dead birds in a backyard flock. A genetic analysis suggested the virus had mutated inside the person, potentially having led to more severe illness, according to AP.
In mid-January, amid heightened influenza activity, the CDC called for subtyping of influenza A viruses in all hospitalized patients on an accelerated timeline. The agency also released a Health Alert Network health advisory, recommending that clinicians collect an exposure history from hospitalized patients with suspected or confirmed influenza to capture any exposure to wild or domestic animals, animal products, or a symptomatic person with a possible or confirmed case of bird flu.
The second bird flu death — from a rare strain, H5N5 — also was reported in a Washington state resident in November, with state health officials noting that the person was an older adult with underlying health conditions who appeared to have contracted the virus from a backyard poultry flock that had contact with wild birds. Officials again said the risk to the public was low.
Since 2024, there have been 71 cases of bird flu, including the two deaths, according to CDC data. But there continues to be no known human-to-human transmission, and the public health risk is still categorized as low.
William Schaffner, MD, from Vanderbilt University Medical Center in Nashville, Tennessee, and a spokesperson for the Infectious Diseases Society of America, explained that starting around 2 years ago, everyone was “very concerned” because H5N1 was spreading in the bird population, and it had gotten into domestic poultry and mammalian hosts, such as dairy cows. There were also “sporadic human cases without obvious transmission to anyone else,” as well as positive serologic tests in people with no memory of a serious respiratory infection.
“However — and very fortunately — it has not exploded,” Schaffner said. “This virus still has not developed a genetic capacity to spread readily in the human population, from person to person.”
He cautioned that it remains “a potential threat, and we have to keep our surveillance systems active in order to track it and to make sure it does not develop that capacity, but I think the general level of concern has diminished somewhat.” He noted that at the beginning of 2025 there was some concern that it would cause a new pandemic, but thankfully “that has not been realized.”
Vigilance requires continued contact with the World Health Organization regarding its international surveillance and using available resources in the U.S. to monitor wild and domestic poultry, dairy cattle, and humans. It also calls for scrutiny of cases of influenza that may appear out of the ordinary, he said. “As always, the public health surveillance system is dependent on alert clinicians.”
There has also been work on a vaccine to protect against bird flu. In November, a phase I trial showed that an intranasal adjuvanted recombinant influenza vaccine appeared to safely prompt a robust response to a range of H5N1 clades.
New cases and outbreaks in animals continue. In December, hundreds of snow geese in Pennsylvania were found dead, believed to have succumbed to bird flu, and poultry owners in Kansas were urged to review safety measures as bird flu spread among avian species there. Additionally, officials in Wisconsin confirmed bird flu was found in a dairy herd there for the first time.
“Right now, we’re at the beginning of the seasonal influenza outbreak,” Schaffner said. “It’s going on concurrent with an increase in COVID, and RSV [respiratory syncytial virus] is just starting.”
He said the public doesn’t need to be concerned about bird flu. Rather, it is important to “focus on the illnesses that are right here and are going to get worse.” Nonetheless, he said, “this is something that remains important to those of us in public health and infectious diseases.”
