US Cuts Bird Flu Vaccine Amid Rising Cases

Since the start of 2025, twelve human cases of the lethal H5N1 bird flu strain have been reported in seven countries, including the United States. Most of the cases were hospitalized, and half have died. These deaths make 2025 the deadliest year since H5N1 began a global resurgence in 2020.

Countries worldwide are ramping up their response to bird flu—Finland has already begun vaccinating at-risk farm workers—but the US seems to be taking a different approach. The government canceled a $700 million bird flu vaccine contract in its latest move. The funding had been intended to support the development of mRNA vaccines for H5N1 and five other subtypes of bird flu. While bird flu is generally thought of as affecting food prices, these viruses were deemed to have pandemic potential. The contract was made to have a vaccine ready as soon as a pandemic emerged.

It’s only the latest in a slew of changes implemented by the new Trump administration targeting bird flu control and prevention programs. Previously, the administration fired over 140 people from the Center for Veterinary Medicine, a Food and Drug Administration subdivision combating various animal diseases like bird flu. These workers had become increasingly important with the arrival of H5N1 in the US in 2022. The FDA was responsible for recalling pet food, a vector for the virus to infect household pets.

Before that, the Trump Administration had also cut workers at the Department of Agriculture (USDA) focused on H5N1 in farmed animals. At the time, bird flu was wreaking havoc on dairy and poultry farms, leading to mass quarantines of dairy cows and record-high egg prices. The USDA firings were almost immediately reversed. However, many other cuts, such as to the FDA, CDC, and other agencies working on bird flu, have yet to be rescinded.

Why is this cancellation significant?

Experts have long warned that bird flu viruses like H5N1 are the most likely cause of the next global pandemic—after all, as many as 26 such pandemics have occurred since the 16th century. It’s difficult to predict what such a pandemic would look like today, but “mild” pandemics like the 2009 pandemic can kill hundreds of thousands, while a severe pandemic like the 1918 flu could kill hundreds of millions.

It’s impossible to predict the exact flu strain that causes the next pandemic, but the H5N1 virus has long raised eyebrows among experts. The virus has already infected hundreds of people in the last few decades, many of them fatally, with clinical signs reminiscent of the 1918 flu. Some cases experience few or no symptoms, making them difficult to diagnose, while others suffer pneumonia and organ failure. The virus also tends to hit those usually thought of as least susceptible to the flu: young adults.

Even more concerningly, H5N1 has demonstrated a robust host range in the last four years, expanding into new animals each year. Previously mainly confined to birds, the virus began to cause massive mammal outbreaks, from mink in Spain and seals in South America to cows in the US. This has worried scientists, who fear that humans could follow suit. If this were to occur, the world would likely be caught unprepared.

The last flu pandemic in 2009 was relatively mild because large segments of the population had cross-immunity that protected them from severe disease. Even so, it increased mortality in young people and revealed shortfalls in the US’s ability to respond. Most notably, even though developing a new vaccine relied on existing flu shot platforms—allowing for a faster vaccine than with COVID—vaccines were only available after the peak of the pandemic, drastically limiting their usefulness.

Vaccines arrived too late during the last flu pandemic, an issue that the Moderna vaccine contract could have addressed. Source

Hoping to avoid a repeat of 2009 with a potentially far deadlier virus, US health officials turned to the pharmaceutical company Moderna for an mRNA H5N1 vaccine.

Without requiring live virus cultures grown in labs, mRNA allows for vaccines to be researched and manufactured more quickly. This aided the COVID-19 response and likely would have helped during the 2009 pandemic when egg-based vaccine manufacturing fell short. The technology also proved to be unexpectedly effective, initially preventing COVID with 90% or greater efficacy. Later, even as effectiveness waned, mRNA vaccines still prevented most cases of severe disease.

Research indicates that preparing even a modestly effective vaccine before the next pandemic could save many lives. Having an mRNA vaccine that is both ready for use and able to be produced faster than other vaccines could have even more benefits.

The cancellation of the Moderna vaccine contract has drawn widespread criticism. Rick Bright, former director of the US Biomedical Advanced Research and Development Authority, emphasized that only mRNA vaccine technology could "come close to matching the need for speed and scale in a pandemic response." Dr. Ashish Jha of Brown University warned that if a pandemic occurred, "we will come to regret this as the day we decided to put the lives of the American people at grave risk."

Should we doubt mRNA?

Unfortunately, there have been many controversies over the use of mRNA vaccines during the COVID-19 pandemic. Recipients reported rare but significant side effects like heart inflammation and blood clots. Combined with the novelty of mRNA technology, which had never been used in vaccines prior to COVID, these complications made people wonder if the vaccines had been safely tested. As immunity waned, the public also began to doubt the usefulness of the vaccines.

However, much of the distrust of mRNA vaccines can be traced to factors other than mRNA technology itself. Many in the US lost faith in vaccines due to vaccine mandates and messaging that either downplayed the side effects of vaccines or oversold their effectiveness. However, these were political messaging and policy issues, not just the result of mRNA technology. Additionally, some criticisms of mRNA technology, such as changing human DNA, were false.

A protest against COVID vaccines and restrictions. Source

Many non-mRNA vaccines had similar issues with side effects while being less effective. In one sense, mRNA vaccines were a more convenient focus of conversation because the technology was newer, and other types of vaccines were not as heavily used in developed countries. However, mRNA technology wasn’t necessarily less safe or effective than other vaccines. It was subject to the same approval process and had an advantage in speed and efficacy.

Even so, the US is limiting the use of mRNA. Since the arrival of the Trump administration, scientists have been told to remove any mention of mRNA technology from grant applications. This can affect the use of mRNA beyond COVID-19, including cancer therapies. In state legislatures, people have even introduced legislation to ban mRNA. In this context, the cancellation of Moderna’s H5N1 vaccine is part of a larger anti-mRNA vaccine trend.

For now, the government could argue that these actions were taken with a healthy dose of skepticism. For now, US leadership sees the Moderna vaccine as an expensive bet. For now, an H5N1 pandemic that kills millions—perhaps even tens or hundreds of millions—is hypothetical. However, one thing is sure: the next global pandemic is not a question of if, but when. Preparing vaccines for a future pandemic is a gambit worth hundreds of millions of dollars, but so is doing the opposite—with countless lives hanging in the balance.