Global Health Expert Shares Insights on Bird Flu

Raj Panjabi, MD, MPH, describes the importance of vigilance, not panic, and precautions that can be taken now to prevent H5N1 avian influenza from spreading to humans

Avian influenza (H5N1), or bird flu, has been in the headlines this spring as reports have emerged of a third human case of infection associated with an ongoing outbreak among dairy cows in multiple states the U.S. The Centers for Disease Control and Prevention has requested that states continue surveillance programs over the summer that monitor for influenza cases. No cases of H5N1 spreading from human to human have been detected to date. But questions about H5N1 and what may happen over the summer are simmering.

Raj Panjabi, MD, MPH, is a faculty member of the Division of Global Health Equity at the Brigham, trained in internal medicine at Mass General, and saw patients for COVID-19 testing and vaccination clinics at MGH Chelsea, MGH and Mass General Brigham community vans from 2020 to 2021. He is also the former White House Senior Director and top pandemic official at the National Security Council under the Biden-Harris Administration (2021-2023). He played a pivotal role in responses to public health crises, including Mpox, influenza and Ebola, and in executing the 2022 National Biodefense and American Pandemic Preparedness Plans.

Panjabi answered questions about steps that can be taken now at the federal and local levels to prevent the spread of bird flu into humans.

Why is an outbreak of bird flu among U.S. dairy cows a potential concern for humans?

There have been cases of pandemic influenza that we know track back to spread into humans from another animal species. In 2009, when I was a resident in the Medical Intensive Care Unit at MGH, I can remember seeing young people present with cases of severe respiratory illness and even respiratory failure as a result of what we called swine flu—a strain of influenza that had spread from pigs into humans and then from human to human. We need to be very vigilant when it comes to influenza in animals. The more influenza that spreads among animal species, especially mammals, the greater the risk of mutations that could spark increased transmissibility from animals to humans, and then from humans to humans. Sustained transmission of infectious disease from human to human that is novel, in other words, when we don’t have prior immunity toward the virus, is what is the harbinger of a human pandemic.

What can be done to prevent an outbreak among people?

I think of it as a four-pronged strategy: Number one is ensuring that we keep communities healthy, safe and informed. Number two is ensuring that our nation’s food supply remains safe. Number three is that we need to safeguard American agriculture and the livelihood and wellbeing of American farmers. And number four is the need to keep monitoring all trends to mitigate risk and prevent the spread of H5N1 among both people and animals.

How does bird flu spread? How did H5N1 get into cows in the first place?

The science so far has shown that wild birds were the first to be infected with this virus. Those birds migrate in a seasonal pattern into the U.S. and descend on poultry farms and dairy farms, infecting local animals. Infection can come from contact with contaminated fluid or excrement. There have been several species of mammals, from seals to cows, that have had confirmed infection with H5N1. That doesn’t necessarily mean the virus is easily transmissible from animal to human, but it does mean that transmission is possible, so we need to lower risk.

Can H5N1 be transmitted from human to human?

While it’s important to remain vigilant, we do not have current evidence of human-to-human spread. That could change. But right now, there isn’t that evidence. The most recent case in Michigan, which occurred on May 30, is the second case of a dairy farmer in the state to test positive. The CDC believes it’s most likely that this was cow-to-human spread rather than human-to-human spread. However, it’s important to note that we still have more work to do to confirm those assumptions, including completing genetic analysis and doing more to enhance testing among exposed individuals.

How concerned should the public be right now?

The message is vigilance, not panic. There are a few important recommendations from the CDC for the public right now. The first is that the CDC discourages drinking raw milk. The second is to avoid exposure to sick or dead animals, including wild birds, poultry, or domesticated birds and other domesticated and wild animals such as cows, where possible. In general, avoid exposure to animal excrement and bedding or materials that have touched or been close to animals with suspected H5N1 infections. For those who have jobs that put them in touch with potentially infected poultry or cows, their risk is higher, and they should take additional precautions.

What can be done to mitigate risk for farmer workers specifically?

The federal government is doing a lot more to enhance testing among dairy farm workers and poultry farm workers who are at highest risk of exposure. Testing includes both antigen testing—which tells us if a person is infected right now—and preparing for serologic testing—which looks for signs in the blood that could indicate a previous infection from H5N1.

Remember, we have tracked H5N1 cases since 1997, as well as other strains around the world. In so many of those situations, it’s farm workers who are the most at risk and most likely to be patient zero. This means we must do a better job of engaging and partnering with them and ensuring that they have proper protective equipment and that sick farm workers get health care.

Many farm workers are uninsured and in the shadows of the healthcare system. Much like during the COVID-19 pandemic when Mass General Brigham worked with community organizations that had earned trust in the community, there needs to be community-oriented methods of partnering with local organizations that have built trust with farm workers to ensure their healthcare needs are met.

Half of migrant farm workers are undocumented and half of undocumented immigrants are uninsured. Of the current states with H5N1 detected on dairy farms, only one - Colorado - provides state-funded healthcare coverage for all adults regardless of immigration status. Limiting undocumented farm workers’ access to healthcare ties the hands of outbreak responders. If States with H5N1 on dairy farms expand Medicaid or other state-funded healthcare coverage to include undocumented immigrants they would reach more farm workers with influenza testing and treatment.

What would elevate concern?

When I was in the White House, there were a few key trends I would look for. First, is there any infection amongst people without links to farms. So far, all the humans we’ve confirmed infection amongst have had direct connections to farms. We also haven’t seen an uptake in flu-like symptoms or an uptick in people presenting with flu-like cases in hospitals.

There are additional ways that we can be on the lookout for spread. One way is through wastewater surveillance, which the federal government has invested in heavily and used for detection of COVID-19 and for Mpox.

We will also be on the lookout for spread from person to person and any sign of increased severity illness symptoms. In the most recent farmworker case, there were symptoms of a cough. However, we have not yet seen symptoms of severe lower respiratory infection such as shortness of breath. Those would be signs that this is changing into something we would be concerned about.