Researchers warn of risks of letting bird flu spread in poultry in the US

Weeks ago, U.S. Health and Human Services Secretary Robert Kennedy Jr. proposed that, to address the avian flu epidemic his country is experiencing, it would be a good idea to let the virus spread in poultry to identify resistant animals. At that moment, all of us who work in the field of animal health and have experience with this virus were shocked by the enormous health, ethical, and economic implications that such a decision could have.

In this article, renowned experts in the fields of human and animal health in the U.S. explain in detail and exhaustively all the reasons why the Health and Human Services Secretary's proposal is unethical, irresponsible, and even dangerous.

Let's remember that, since 2021, we have been experiencing the most serious avian flu epidemic in history, with every continent affected except Oceania. One of the hotspots of the epidemic is precisely the United States, where the virus has caused devastating outbreaks not only in poultry (more than 170 million birds have died or had to be euthanised), but also in wildlife, dairy cows (with more than 1,000 farms affected), and humans with at least 71 confirmed cases.

The strategy of allowing a highly pathogenic virus with pandemic potential like H5N1 to spread unchecked among US livestock species has no scientific or technical basis and no international health authority has endorsed it. This proposal adds to the long list of controversial and dangerous public health measures the US administration has taken in the last year.

Since the massive outbreaks in poultry in the US began in 2022, we have already seen that the virus that kills chickens and turkeys does not remain on poultry farms, but jumps to new hosts, establishing complex and dangerous chains of transmission. From these farms, the virus has spread to dairy cows, wild birds, various mammal species, including cats, and, of course, people. Although most human cases have been mild, we must remember that four have people required hospitalisation and one person died. Furthermore, the most severe cases have occurred precisely through contact with infected poultry.

In contrast to the "natural selection" strategy, the scientific community and the veterinary profession propose acting against the virus on multiple fronts to minimise the impact on human and animal health. Among the available tools, mass vaccination of poultry against H5 stands out as a priority. Other countries, such as China and France, have implemented avian influenza prevention and control plans based on scientific evidence, focusing on mass vaccination programs, active surveillance, and improvements in farm biosecurity. Both countries have achieved very satisfactory results, not only in animal welfare and health, but also in drastically reducing the risk to human health.

These comprehensive prevention and control programs are costly both financially and logistically, but they are much more cost-effective than the strategy of allowing a zoonotic pathogen like H5N1 avian influenza to spread unchecked among animals, causing catastrophic effects on livestock production, food security, biodiversity, and human health.