What you need to know

• Although bird flu continues to spread in wild birds, livestock, and humans, the risk to the public remains low.
• The majority of U.S. bird flu cases have been reported in farm workers who had direct contact with infected birds and cattle. Health officials are working to monitor the spread of the virus and improve protections for those most at risk.
• Recent data suggests that mutations in bird flu viruses could make them more dangerous to humans and potentially increase the risk of a pandemic.
• On January 6, Louisiana health officials confirmed the first U.S. death from bird flu.

Throughout 2024, dozens of human cases of H5N1 bird flu were detected as the virus spreads rapidly in livestock. The current risk to humans is low but not nonexistent. Here’s everything you need to know about the current status and future outlook of H5 bird flu in the United States.

Current U.S. bird flu status (as of January 6, 2025)

As of January 6, 66 human bird flu cases have been reported in eight states. Over half of all cases are in California. The state’s governor declared a state of emergency as a “proactive” action against bird flu on December 18. 

On January 6, the Louisiana Department of Health reported the first U.S. bird flu death. The patient, a man over age 65, was previously confirmed to be the first severe bird flu case in the U.S. and the first case linked to backyard flocks. The department emphasized that the risk to the public is low and that no new cases or evidence of human transmission have been detected in the state.

All but two human bird flu cases this year were in farm workers who were exposed to infected livestock. The exposure source of the remaining cases—one in California and one in Missouri—is unknown. 

The CDC reported on November 22 that a child in California tested positive for bird flu, the first known pediatric bird flu case in the U.S. However, it is unclear how the child contracted the virus, as they had no known contact with infected animals. 

To date, there have been no reports of human transmission of bird flu during the current outbreak. Additionally, most human cases have not been severe, and no deaths have been reported. For these reasons, experts are confident that the bird flu risk to humans remains low. 

“In the short term, there is very little threat,” Dr. Scott Roberts, an infectious diseases specialist with Yale Medicine said. “The risk for the general public is so low,” he emphasized to Yale Medicine.

How the U.S. is monitoring bird flu 

The CDC continues to monitor the circulation of bird flu in humans as part of its year-round flu monitoring. The agency is also working to improve protections for farm workers, who are at the highest risk of contracting bird flu.

In November 2024, the CDC also announced expanded actions and updated guidance for farm workers, including improved access to and training for using personal protective equipment (such as N95 face masks), more rigorous testing procedures, and increased outreach. These updates followed a CDC report finding that 7 percent of participating dairy workers had signs of a recent bird flu infection. A second CDC study, also released in November, found inadequate use of personal protective equipment among dairy workers on farms with bird flu outbreaks. 

After the H5N1 virus was found in raw milk being sold in California, the U.S. Department of Agriculture announced on December 6 that unpasteurized milk must be tested for bird flu. The USDA order also requires dairy farms with positive bird flu cases to cooperate with health officials in disease surveillance. 

Is a bird flu pandemic possible?

In early November, a Canadian teen was hospitalized with bird flu caused by a virus that’s closely related to the H5N1 virus circulating in the U.S. The case has troubled experts for a few reasons. 

First, it is Canada’s first human bird flu case where the patient was not infected while traveling, and the source of exposure is unknown. Second, the teen experienced severe symptoms and developed a lung infection requiring critical care, raising concern that bird flu infections may be more severe in younger people. 

The final and biggest concern about the case is that genetic analysis revealed several changes in the virus’s DNA sequence, called mutations, that could potentially make the virus better able to infect humans. Researchers say that two of those mutations could make it easier for the virus to infect humans, and another one may make it easier for the virus to replicate after infecting a human. However, it’s unclear if the changes occurred before or after the teen was infected.

Scott Hensley, a professor of microbiology at the University of Pennsylvania, told Nature that “this should serve as a warning: this virus has the capacity to switch very quickly into a form that can cause severe disease.”

Notably, even in this more severe case, there is still no evidence of human transmission, which is necessary for a potential bird flu pandemic. However, the case underscores the risk of new and potentially dangerous mutations emerging as the H5N1 virus continues to spread and multiply. 

A study published in Science on December 5 found that a genetic change on a protein on the surface of the virus could make it easier for the virus to attach to and infect human cells. But none of the mutations observed in the Canadian case are those identified in the study. 

Importantly, the researchers stressed that the ability of the virus to attach to a specific part of human cells “is not the only [factor] required for human-to-human transmission of influenza viruses.” 

How to stay safe

Most people are not at high risk of being exposed to bird flu. The virus is spreading between animals and from animals to humans through direct contact. The CDC recommends avoiding the consumption of raw milk products and direct contact with wild birds and potentially infected livestock. 

“Pasteurization kills the bird flu virus and other harmful germs that can be found in raw milk,” says a November 24 California Department of Public Health press release. “CDPH advises consumers not to drink raw milk or eat raw milk products due to the risk of foodborne illnesses.”

Additionally, although the annual flu shot does not protect against bird flu, getting vaccinated helps prevent infection with seasonal flu and bird flu at the same time. In very rare instances, getting infected by two influenza viruses at the same time can result in a combination of genetic material that produces a new virus. 

This phenomenon, known as antigenic shift, triggered the 2009 swine flu pandemic.

Learn more about how to protect yourself and your loved ones against bird flu.

For more information, talk to your health care provider.

This article first appeared on Public Good News and is republished here under a Creative Commons license.