Why bird flu isn’t the next pandemic — yet

Bird flu has been tearing through poultry for several years now, infecting birds and prompting the wholesale slaughter of flocks. Since 2022, in fact, more than 150 million poultry birds have been killed nationwide in an effort to combat the spread, according to the U.S. Department of Agriculture.

Now, the USDA reports, infections have been found in cattle in California and Nevada. The good news: So far, only a few dozen humans have been infected, the majority of whom worked with infected animals. Still, many people, nervous after the Covid-19 pandemic, fear that for humans, the consequences of bird flu might become more than just expensive and hard-to-find eggs.

RED asked David Merriam, Ph.D., an assistant professor of Biology at Metropolitan State University of Denver and an expert in vaccine safety and diseases that are passed from animals to humans, to weigh in on the risk and what we can do about it.

How worried should we be about the potential for a bird-flu epidemic or pandemic?

We don’t need to panic yet. Right now, the rate of transmission from bird to person or cow to person is very low. The major strain that is a concern, H5N1, has been around a long time — it was first identified in Asia in 1996.

We can worry about a lot of different diseases that are out there now, but the bird-flu virus requires a mutation to make it transmissible from human to human. Until that happens, the risk to most of us is very low.

Is it safe to eat eggs (assuming you can find and afford them) and chicken? Is milk safe?

Yes. Milk is safe as long as it’s pasteurized. And if you’re cooking eggs and cooking your chicken, then it’s safe. Heat is one of the best defenses against pathogens. The virus is not going to survive pasteurization or the cooking process. However, consumption of raw milk — unpasteurized milk — is a concern. It doesn’t go through that heating process.

Other than culling infected flocks and herds, what steps can or should be taken to try to curtail the spread?

Constant vigilance is a good thing. The sooner you catch something in a flock, the sooner you can stop it. This virus doesn’t have a long incubation period, so hopefully, separating the infected animals from the rest of the flock could prevent it from spreading.

If there are symptoms or birds in the area are infected, keep them isolated. And in general, it’s important to keep the cages up to date, functioning and clean. Good hygiene is important in animals just like in humans.

We have flu vaccines now, and millions get them every year. Will those vaccines protect us? Or at least increase our resistance to the virus?

It’s not likely. There is a lot of genetic variability in the flu virus, and every year the vaccine is made up based on the best guess about what strains will be circulating. Some years, the guess isn’t right — that is why some years the flu shot doesn’t seem very effective.

That said, it’s always possible the flu shot could provide some cross-protection, like how people who got the smallpox vaccine were somewhat protected against mpox, because although they are different viruses, they are in the same family.

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If the bird-flu virus does mutate so that it spreads from human to human, how effective do you think masks would be?

I would 100% say that masks are the first, best prevention tool. I mean, remember, surgeons are wearing masks in the operating room. Any time anyone is in a room where they’re really worried about keeping things sterile, they’re wearing a mask.

Are they perfect protection? No. But they are one way to lessen the chance of transmission. And if you’re a chicken farmer, you do probably want to wear a mask now.

Where are we in terms of formulating a vaccine to protect against bird flu?

I’m sure they’re looking into it. But I would caution that the strain that exists now doesn’t go to humans easily. It will only go from human to human easily if there is a major mutation in the virus. So a vaccine developed to combat the strain circulating now would not be very effective against the virus once it mutates into one that is transmitted from human to human.

If there is a major mutation (making human-to-human transmission more likely), I’m sure, even in this current environment, there would be a massive flood of money and resources into an effort to develop a vaccine.

As someone paying close attention to the bird flu situation, is there anything you have learned recently that might be of interest? 

A lot of the wild animals being caught and testing positive for avian flu have been cats. Generally, those have been barn cats on dairy farms and feral cats. Evidence suggests cats can be infected with the virus through exposure to infected birds and cattle, as well as by drinking unpasteurized milk. I don’t want to make anyone worry that kitty is infected, but if you live in an area with known infection, it’s a good idea to keep your cats indoors.