6 things to help decipher avian flu worries

U.S. health agencies are rapidly responding to avian influenza spreading among several dairy herds across multiple states and two large poultry facilities in recent weeks and infected one dairy worker in Texas.

Public health experts have worried for decades that avian influenza could pose a significant pandemic threat if the virus became capable of spreading from human to human because of how deadly it could be.

Between Jan. 1, 2003, and Feb. 26, 2024, there were 887 global cases of human H5N1 avian influenza, according to the World Health Organization. Of those, 462 cases were fatal.

The Texas dairy worker has experienced only mild symptoms — pink eye — and is expected to fully recover, according to the CDC.

Here’s what you need to know: 

What is the government doing?

White House spokesperson Karine Jean-Pierre said at a briefing this week that the Biden administration is monitoring avian influenza and is taking steps to ensure the risk to human health remains low.

“The White House and our Office of Pandemic Preparedness and Response Policy immediately stood up a response team with relevant agencies like CDC, FDA and USDA to ensure that we are doing everything in our power to ensure we keep communities healthy, safe and informed, ensure that our Nation’s food supply remains safe and monitor any and all trends to mitigate risk and prevent the spread of avian flu,” Jean-Pierre said.

Some state governments have introduced new limitations for cattle moving across state lines, such as testing and temporary quarantines. The USDA has launched standing weekly meetings about the outbreak with congressional staff focused on agriculture, according to a department spokesperson.

“This [highly pathogenic avian influenza] event is like a fire alarm,” said Taylor Sexton, a former senior adviser to Robert Kadlec, who was the assistant secretary of Health and Human Services for Preparedness and Response in the Trump administration. “We should treat it like it is real and an opportunity to practice U.S. capabilities.”

Why are public health experts concerned?

Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials, said the CDC is working to coordinate a public health response if “things take a turn to a more worrisome state.”

“I’m not hearing anybody say that we necessarily think that’s going to happen,” Plescia said. “But nobody is willing to say, ‘It will be okay, don’t worry about it.’”

Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health, agreed that the risk to the general public is low. But she said more needs to be done to protect dairy workers — including possibly rolling out targeted vaccines for the H5N1 strain of the virus identified in the Texas dairy worker.

“I don’t see any evidence that this is going to be spreading ... from human to human,” Nuzzo said. “But we should be doing surveillance, not just in dairy herds, but also dairy workers who are exposed to make sure they are not getting sick.”

Farmworker groups have warned that because most dairy workers have tenuous immigration and job status, they might be less likely to report illness out of fear of retaliation.

“There's also not enough information or any information being put out by the government on how farmworkers should be protecting themselves, if at all,” said Amy Tamayo, policy and advocacy director for Alianza Nacional de Campesinas, a national womens’ farmworkers organization.  

Is the food supply safe?

The food supply remains safe, federal officials and public health experts say. Milk must be pasteurized — or heated temporarily to kill bacteria and other harmful germs — before being sold across state lines. The vast majority of milk sold in grocery stores is pasteurized.

“We continue to feel for certain that pasteurized milk is perfectly fine for people to drink,” Plescia said. “We've always been worried about people drinking raw milk.”

The FDA has long discouraged drinking raw or unpasteurized milk, although several states have recently loosened regulations around its sale in grocery stores. Federal officials recommend dumping milk from livestock that have been exposed to the disease, even if they never showed symptoms. After a herd recovers from illness, the FDA recommends testing milk for the virus before resuming the selling of it.

Pasteurization regulations, which have been in place for decades, have “a number of requirements that we believe will ensure the safety of the milk supply,” FDA Deputy Commissioner for Human Foods Jim Jones said in a webinar Friday morning.

What do we know about vaccines for avian flu? 

Top FDA vaccine regulator Peter Marks said Monday at a global vaccine conference that the U.S. has a stockpile of vaccines for avian influenza.

“We believe that, if we needed to, they would be reasonably good matches,” Marks said. WHO officials also said earlier this week that avian flu vaccines — and antiviral medicines — would work for the virus currently spreading.

But Dr. Luciana Borio, a former FDA official and biodefense expert, questioned the effectiveness of the shots if they needed to be deployed.

The USDA has tested potential vaccines for poultry to prevent the spread of a disease that is lethal to birds. But a mass vaccination campaign for birds could have trade ramifications, and Agriculture Secretary Tom Vilsack told lawmakers last year that an effective vaccine was still “a long way away.”

What do we know about the Texas case? 

The CDC conducted a genomic analysis of the virus from a sample taken from the Texas dairy worker. The results did not change the agency’s assessment that the risk to humans remains low.

“While minor changes were identified in the virus sequence from the patient specimen compared to the viral sequences from cattle, both cattle and human sequences maintain primarily avian genetic characteristics and for the most part lack changes that would make them better adapted to infect mammals,” the CDC said.

How many animals have gotten sick?

The USDA has confirmed outbreaks in 15 herds across six states, and officials are expecting positive results from symptomatic herds in several other states.

Among these herds, an average of roughly 10 percent of the cows have become sick, with symptoms including low appetite, fever and reduced milk production. Most cows have recovered and the USDA does not require culling sick animals, unlike the protocol for poultry that contract avian flu.

A major egg producer in Texas — Cal-Maine Foods — recently euthanized more than 1 million birds after they tested positive for the virus.