Jennifer Nuzzo is a nationally and globally recognized leader on global health security, public health preparedness and response, and health systems resilience. Together with colleagues from the Nuclear Threat Initiative and Economist Impact, she co-leads the development of the first-ever Global Health Security Index, which benchmarks 195 countries’ public health and healthcare capacities and capabilities, their commitment to international norms and global health security financing, and socioeconomic, political, and environmental risk environments.
In addition to her scholarly work, Nuzzo regularly advises national governments and for-profit and nonprofit organizations on pandemic preparedness and response, including during the COVID-19 pandemic. She is a pandemic advisor for Impact Assets’ Stop the Spread Campaign. She is currently a member of the National Academies of Sciences, Engineering and Medicine’s (NASEM) Standing Committee for the Centers for Disease Control and Prevention (CDC) Center for Preparedness and Response.
Her articles have appeared in The New York Times, The Washington Post, USA Today, Fox News, Politico, The Hill, and The Boston Globe. She was featured in Debunking Borat, a television series on Amazon Prime Video, and her work was featured on Last Week Tonight with John Oliver. She served as COVID Advisor for the Borat Subsequent Moviefilm.
Bird flu's unprecedented spread among livestock and other mammals in the U.S. has raised fears that another pandemic could be in store.
The incoming Trump administration will have to prepare for this risk. As H5N1 spills into more people and animals, scientists warn it could evolve to better infect humans and become more dangerous.
Trump and his picks to helm federal health agencies have largely been silent on bird flu. The messaging so far — and the track record of those Trump has chosen to oversee a potential bird flu crisis — is "worrisome," says Dr. Andrew Pavia, professor of medicine at the University of Utah who's worked on influenza pandemic preparedness for more than two decades.
The transition team did not respond to NPR's request for comment on its plans.
Trump's choice to lead the Department of Health and Human Services, Robert F Kennedy Jr., has an extensive history of making inaccurate and misleading statements on vaccines and infectious diseases. He's a lawyer who for years led an advocacy group that is a major player in the anti-vaccine movement, promoting the long-debunked idea that vaccines lead to autism, among other false claims.
Kennedy denies spreading misinformation, though his criticism of vaccines is well known.
He's also made specific comments undermining trust in the bird flu vaccines. In an online post last summer, he claimed there's "no evidence" the licensed shots for the national stockpile will work and that they "appear dangerous."
And he suggested in another post that "someone" might bioengineer a dangerous form of the virus to profit off the vaccine.
Scientists who study the vaccines are deeply troubled by these statements.
"They are false, baseless and inaccurate," says Dr. Paul Offit, director of the Vaccine Education Center at the Children's Hospital of Philadelphia.
Kennedy has also discussed having the National Institutes of Health take a break from infectious disease research for eight years, and replacing hundreds of employees there.
Trump himself suggested last spring that he'd like to disband an office in the executive branch that handles pandemics.
If confirmed as health secretary, Kennedy would have broad powers. He could declare a public health emergency, control and direct funding, and influence key decisions at the Centers for Disease Control and Prevention, the Food and Drug Administration, and NIH, all of which are overseen by HHS.
"At every step, he can certainly play a role in hampering or being a barrier," says Syra Madad, director of the special pathogens program at NYC Health + Hospitals.
This could be of huge consequence for how prepared the country is to face an escalating crisis. Still, some scientists point to the first Trump administration's speedy work on a COVID-19 vaccine with Operation Warp Speed, and say they think that ultimately Kennedy would need to listen to Trump if he called for a similar effort.
"If the president tells him to do something, I would hope that would be the case," says Dr. Carlos del Rio, a professor of medicine at Emory University. "And let's be honest, there has been a lot of failure in the current response."
An urgent need to prepare
Bird flu currently doesn't pose an imminent threat to the American public — most of the 67 human cases since last April have only led to mild illness and were caused by direct exposure to infected animals.
But, scientists caution, things could change quickly.
"This is like some brush burning around your house," says Dr. Jesse Goodman, an infectious disease physician at Georgetown University and a former FDA official.
"You better pay attention because it could turn into something else."
To prepare for this threat, the U.S. must strengthen the pipeline of vaccines and treatments for bird flu, says Pavia. The Trump administration will need to help bolster supplies of the existing shots and support development of new ones.
"We are fooling ourselves that we have enough vaccine capacity and the ability to respond quickly," he warns.
Already under the Biden administration, scientists have criticized the federal government for the slow pace of its response.
"There's a lot of work that still needs to be done," says Jennifer Nuzzo, who directs the Pandemic Center at Brown University School of Public Health, adding that it's not like "handing over the keys to the car with the engine running."
Two weeks ago — more than nine months after the outbreak was first detected in cattle — health officials announced an investment of more than $300 million into pandemic readiness for bird flu. It wasn't until December that the federal government took key steps to track the spread in dairy cattle.
"We're flying blind just like we did during COVID-19," says Madad.
Alongside vaccines, public health experts have outlined a list of urgent tasks to battle bird flu, including: working with the industry to improve biosecurity measures and testing on farms; coordinating with state and local authorities on the ground; and planning for contingencies.
There are gaps in disease surveillance efforts on farms. And ultimately public health agencies have limited authority in this area, says Dr. Luciana Borio who served as the FDA's chief acting scientist from 2015 to 2017 and is now a fellow at the Council on Foreign Relations.
"That means we have to put even more effort into developing new vaccines and therapeutics more quickly," she says. "We can't just hope that this is going to go away."
Casting doubt on vaccines
Kennedy has grabbed headlines for promoting raw milk despite the public health warnings that it can harbor the bird flu virus. His views on vaccines could be even more consequential.
The Health Secretary could influence the rollout of a vaccine campaign and communication with the public. While it's rare to do so, he could even override FDA decisions on vaccine approvals and authorizations, and how the CDC comes up with recommendations, notes James Hodge, a law professor at Arizona State University.
"There's much he could do to disrupt vaccine programs in this country," says Offit. "I have little doubt that were he to pass his confirmation hearing, that's exactly what he'll do."
Last year, Kennedy took direct aim at bird flu vaccines in several posts on X.
He cited the pharmaceutical industry's financial interest in developing bird flu vaccines and he raised a conspiracy theory, suggesting that the government's work on bird flu vaccines may be in anticipation of a "lab-derived pandemic."
In June, he wrote: "With so much money on the table, is it conceivable that someone might deliberately release a bioengineered bird flu?"
Dr. Andrew Pekosz calls the idea "preposterous," and points out that developing vaccines ahead of time is exactly what needs to be done, in case a crisis emerges in the future.
"This is the planning and preparedness that public health officials and scientists do to be ready to respond," says Pekosz, a professor of microbiology at Johns Hopkins Bloomberg School of Public Health. "Those vaccines could be the primary way we protect our population from a potential H5N1 pandemic."
And contrary to Kennedy's statement raising a safety concern, the existing bird flu vaccines, as with the seasonal influenza shots, "have shown a safety record," he says. "They're not dangerous."
Those vaccines were developed to target older strains of bird flu and approved based on clinical data that looked at their safety and the immune response the vaccines elicited in participants.
The federal government is now having manufacturers update these shots to more closely target the strain of bird flu in circulation — similar to what's done with seasonal influenza every year — and is gathering more data based on new studies, which aren't yet published.
It's expected there will be about 10 million doses stockpiled by the spring.
Kennedy's claim there's "no evidence" the vaccines will work is misleading because their effectiveness can only be determined in human trials once a bird flu virus is actually spreading between people, says Michael Osterholm, director of the Center for Infectious Disease Research and Policy.
"There's no way we could know because we don't have the virus that's going to cause the next pandemic yet," he says.
However, health officials have noted that the newer vaccines, ordered by the federal government for the national stockpile, appear well-matched against the virus circulating in animals, according to lab research on the immune response they generate.
There is also separate data published last July showing the originally licensed vaccines induce antibodies "that likely would be protective" against the current strain, says Offit, though you can't know for sure without vaccine effectiveness studies.
If the virus changes significantly and begins spreading among people, it's entirely possible the vaccine will need to be updated further. That's why the federal government is not preemptively manufacturing hundreds of millions of doses right now, according to David Boucher, a senior official with the Administration for Strategic Preparedness and Response.
'A swift response'
In the event of a bird flu pandemic, Nuzzo says she expects Americans will "demand" vaccines, given just how deadly this virus might be.
"What I am worried about is whether any ideological opposition, or perhaps lack of understanding of science, gets in the way of a swift response," she says.
If the virus started spreading among humans, the country would not be able to manufacture all the needed shots in a rapid timeframe.
It would take about six months to churn out 150 million doses, and even longer if the virus had changed enough to warrant another update, says Boucher. And that's still not nearly enough to protect the entire U.S. population of more than 330 million people.
These concerns have prompted the federal government to invest in mRNA vaccine technology for bird flu as was done for COVID-19. These shots could be manufactured in a much faster timeframe.
Borio believes the government's work to accelerate development on new bird flu vaccines will continue under Trump, based on her experience working under the first Trump administration.
"No president or Congress wants to see people dying needlessly of an influenza pandemic," she says.
For his part, Trump's pick to lead the FDA, Dr. Marty Makary, has pushed back on concerns that Kennedy's stance on vaccines should disqualify him from being secretary.
But this transition period is a delicate moment, when the country could be caught off guard if the situation suddenly changes, says Goodman, who recommends the Biden administration share its pandemic playbook so incoming officials can game out different pandemic scenarios and assess readiness. He also cautions that Trump's team needs to preserve the federal workforce, including the career scientists, who have the knowledge on bird flu and pandemics.
"You want to keep the best people, not scare them away," with "extreme rhetoric," he says.
As Trump brings in new people, Pavia hopes he taps those with bird flu expertise, saying there are plenty of "conservative choices," with backgrounds in biodefense and the military. After all, it was President George W. Bush who emphasized the threat of bird flu 20 years ago.
"What you can't do is bring in novices. You can't bring in people who don't have any experience with the diseases or with the complexities of a response," he says. "Mother Nature doesn't care what your politics or your policies are."
NEW YORK (AP) — The Biden administration on Tuesday released a “roadmap” for maintaining government defenses against infectious diseases, just as President-elect Donald Trump pledges to dismantle some of them.
The 16-page report recaps steps taken in the last four years against COVID-19, mpox and other diseases, including vaccination efforts and the use of wastewater and other measures to spot signs of erupting disease outbreaks. It’s a public version of a roughly 300-page pandemic-prevention playbook that Biden officials say they are providing to the incoming administration.
Biden officials touted the steps they took to halt or prevent disease threats, but some public heath researchers offer a more mixed assessment of the administration’s efforts. Several experts, for example, said not nearly enough has been done to make sure an expanding bird flu pandemic in animals doesn’t turn into a global health catastrophe for people.
“Overwhelmingly you’ve heard a lot of frustration by outside experts that we’ve been under-reacting to what we see as really serious threat,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health.
Public health experts worry the next administration could do less
Trump and his team plan to slash government spending, and Trump has endorsed prominent vaccine detractors for top government health posts. During the campaign last year, Trump told Time magazine that he would disband the White House office focused on pandemic preparedness, calling it “a very expensive solution to something that won’t work.”
Public health researchers also point to Trump’s first administration, when the White House in 2018 dismantled a National Security Council pandemic unit. When COVID-19 hit two years later, the government’s disjointed response prompted some experts to argue that the unit could have helped a faster and more uniform response.
In 2020, during the pandemic, Trump officials moved to pull the U.S. out of the World Health Organization. President Joe Biden reversed the decision, but Trump’s team is expected to do it again. Experts say such a move would, among other things, hurt the ability to gain information about emerging new outbreaks before they comes to U.S. shores.
Officials with the Trump transition team did not respond to emails requesting information about its pandemic planning.
Many public health experts praise Trump for “ Operation Warp Speed, ” which helped spur the rapid development of COVID-19 vaccines. But several also noted that decades of planning and research under previous administrations laid the groundwork for it.
What do Biden officials say they accomplished?
COVID-19 vaccines did not start to trickle out to the public until after Biden defeated Trump in the 2020 election, and it was the Biden administration that stood up what it describes as the largest free vaccination program in U.S. history.
“President Biden came to office amidst the worst public health crisis in more than a century,” said Dr. Paul Friedrichs, director of the White House Office of Pandemic Preparedness and Response Policy, in a statement. “He partnered with stakeholders across the nation and turned it around, ending the pandemic and saving countless lives.”
Friedrichs’s office was established by Congress in 2022. He said the administration has “laid the foundation for faster and more effective responses to save lives now and in the future.”
What has been done to prepare for bird flu and other threats?
The pandemic office, which released the report Tuesday, said it has taken steps to fight bird flu, which has been spreading among animal species in scores of countries in the last few years.
The virus was detected in U.S. dairy herds in March. At least 66 people in the U.S. have been diagnosed with infections, the vast majority of them dairy or poultry workers who had mild infections. But that count includes an elderly Louisiana man who died.
Among other steps, the administration is stockpiling 10 million doses of vaccine that is considered effective against the strain that’s been circulating in U.S. cattle, and spent $176 million to develop mRNA vaccines that could quickly be adapted to mutations in the virus, with late stage trials “beginning shortly,” the document says.
READ MORE: Louisiana patient is the first to die of bird flu in the U.S., health officials say
Having measures in place to quickly develop and mass produce new vaccines is crucial, said Michael Osterholm, a University of Minnesota expert on infectious diseases.
“We don’t really have any understanding of what influenza virus will emerge one day to cause the next pandemic,” Osterholm said. “It sure isn’t this (bird flu strain), or it would be causing it (a pandemic) right now.”
The U.S. should maintain collaborations that train disease investigators in other countries to detect emerging infections, public health experts say.
“We have to continue to invest in surveillance in areas where we think these infectious agents are likely to emerge,” said Ian Lipkin, an infectious diseases researcher at New York’s Columbia University.
“I’m hoping that the Trump administration — as they are concerned about people coming across the border who may be infected with this or that or the other thing — will see the wisdom in trying to make sure that we do surveillance in areas where we think there’s a large risk,” he said.
The Biden administration has been pumping money out the door to fund bird flu preparedness programs before the Trump team takes over, leaving public health officials grateful even as they insist the incoming president will need to do more once he’s in office.
“This is a good down payment on funding for what is currently a limited number of human cases acquired directly from infected animals. It is not adequate funding for preparing for a potential pandemic,” said Jennifer Nuzzo, director of the Pandemic Center at Brown University School of Public Health.
The Department of Health and Human Services announced in early January it would be awarding over $300 million in funding for bird flu response efforts, including $186 million through the Administration for Strategic Preparedness and Response for preparedness efforts like training for hospital staff, special units for infectious diseases and personal protective equipment stockpiles.
David Boucher, ASPR’s director of infectious disease preparedness and response, told NOTUS that the incoming Trump administration’s potential views on H5N1 were not considered when deciding which programs to allocate funds to and when. But he said that almost all of the recently announced funding has already been obligated to specific contracts and grants.
“Where we are focusing on the transition is to make sure that it’s smooth, so that our response to H5N1 carries through and we don’t have any disruptions,” he said. “We want a seamless transition to make sure that we’re giving the best response possible to the American public.”
The current H5N1 outbreak began in early 2024. Cases have been detected in wild birds, poultry and cattle — along with over 60 confirmed human cases, mostly in agricultural workers. One person with severe H5N1 died in early January.
A health care lobbyist, who asked to remain anonymous in order to remain on good terms with the incoming Trump administration, said public health advocacy groups involved in the bird flu response are waiting to see how HHS secretary nominee Robert F. Kennedy Jr. may influence public health policy. Kennedy has repeatedly implied that bird flu was created in a lab, potentially with the knowledge of the government, a theory that is not supported by evidence.
Kennedy and the Trump transition team did not respond to requests for comment.
“I think there’s a lot of question marks about the stance that the administration is going to take. [Trump’s first administration] obviously presided over a wildly successful program in Operation Warp Speed, but that has caused some friction within the Republican caucus and the Republican Party,” the lobbyist said. “It’s hard to know who will be calling the shots on the response and what they will want to do. So I think there’s definitely concern, but certainly hope that they will continue preparing in the same way that the Biden administration has.”
But New York State Health Commissioner James McDonald told NOTUS that the every-other-week phone calls he’s had with HHS throughout the current bird flu outbreaks aren’t currently scheduled to continue past Jan. 20.
“They’re waiting for the new administration to see what they want to do,” McDonald said.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota and a former member of HHS’ COVID-19 advisory committee, said that while the Biden funding was “a start,” it wasn’t enough. What the U.S. really needs to be prepared for a future pandemic, Osterholm said, is sustained investment in vaccine development and manufacturing — because once a serious outbreak actually starts, it’s already too late.
“When you have a pandemic begin, it’ll happen real fast, and it’s like falling off a cliff,” Osterholm said. “Imagine you’ve just walked miles and miles on a perfectly flat piece of ground, and then you take one more step and you’re 24 inches off the edge of the cliff, and it’s five miles straight down. That’s where we’re at. We don’t know how close we are to the edge of that cliff.”
But the U.S.’s vaccine manufacturing capacity is far below what would be needed to adequately protect the population should H5N1 become a widespread pandemic, Osterholm said — and the 60 million doses of antiviral drug Tamiflu the U.S. has stockpiled won’t be enough if H5N1 becomes widely transmitted between humans.
“That won’t stop transmission. At best, it will reduce serious illness and deaths, but it won’t stop the pandemic, and of course, it won’t even begin to address what’s happening globally,” Osterholm said.
The chances of the incoming administration making a large investment in vaccines may be slim. Kennedy, a longtime vaccine skeptic, has said he would give infectious disease research a “break.” And Trump has said he would support efforts by Kennedy to investigate if vaccines cause autism, a claim that has been debunked.
“I worry about the fact that a lot of people who will be in health decision making positions will be new to the job,” Nuzzo said. “We lost a lot of experienced people due to political attacks and general attrition during COVID-19.”
But regardless of staffing challenges, Nuzzo said she believes the incoming administration will be forced to act on H5N1 — if not because of the public health risk, then because of the threat it poses to the economy. Nuzzo pointed to egg shortages and the loss of income to dairy farmers as examples of H5N1’s economic impacts.
“For an administration that was elected in part because of the cost of grocery bills, I don’t see a scenario in which they can ignore H5N1 and still answer the political mill that is hoping for a safe, healthy and inexpensive food supply,” Nuzzo said.
—
Margaret Manto is a NOTUS reporter and an Allbritton Journalism Institute fellow.
Yesterday, health officials in Louisiana announced that a patient who was hospitalized with severe bird flu in December has died. The individual contracted bird flu after exposure to a backyard flock and wild birds. It is the first death recorded in the United States attributed to H5N1, or avian influenza.
The person was over the age of 65 and reportedly had underlying medical conditions. The Louisiana Health Department has not released any more details about the patient.
A total of 66 people in the US tested positive for bird flu in 2024, according to the Centers for Disease Control and Prevention. In all of the other cases, people developed mild symptoms and made a full recovery. But the Louisiana case is a stark reminder that avian flu can be dangerous. And as the number of human infections rises, health experts worry about more cases of severe illness—and potentially more deaths.
“This is an ongoing game of Russian roulette,” says physician Nahid Bhadelia, founding director of the Center on Emerging Infectious Diseases at Boston University. “The more virus there is in our environ
ment, the more chances there are for it to come into contact with humans.” It was only a matter of time before bird flu turned deadly, she says.
The US is in the middle of an H5N1 outbreak that shows no signs of stopping. The virus has infected more than 130 million birds, including commercial poultry, since January 2022. In April 2024 it spilled into dairy cows for the first time. Though not fatal for cows, the virus has sickened more than 900 dairy herds in 16 states.
Most people who come down with bird flu are farm workers or others who have direct contact with sick animals. Of the 66 confirmed infections in the US last year, 40 had exposure to dairy cows, while 23 had exposure to poultry and culling operations. In the three other cases, the exact source of exposure is unknown.
Since 2003, more than 850 human cases of H5N1 bird flu have been reported outside the United States, and about half of those have resulted in death. In a statement released Monday, the CDC said a death from H5N1 bird flu “is not unexpected because of the known potential for infection with these viruses to cause severe illness and death.” Federal health officials say the risk of getting bird flu remains low for the general public, and there is no evidence that the virus is spreading from person to person anywhere in the country.
One of the puzzling aspects of the current US outbreak is why all the human infections until now have resulted in mild illness. “It could be that they're young, healthy people,” says Jennifer Nuzzo, director of the Pandemic Center and a professor of epidemiology at Brown University. “It could be that the way they're being exposed is different from how we've historically seen people get infected. There are a number of hypotheses, but at this point they're all just guesses.”
Nuzzo says it’s very possible that the Louisiana patient’s preexisting health conditions contributed to the severity of their illness, but also points to the case of a teenager in Canada who was hospitalized with bird flu in November.
The 13-year-old girl was initially seen at an emergency department in British Columbia for a fever and conjunctivitis in both eyes. She was discharged home without treatment and later developed a cough, vomiting, and diarrhea. She wound up back in the emergency department in respiratory distress a few days later. She was admitted to the pediatric intensive care unit and went into respiratory failure but eventually recovered after treatment. According to a case report published in the New England Journal of Medicine, the girl had a history of mild asthma and an elevated body-mass index. It’s unknown how she caught the virus.
“What that tells us is that we have no idea who is going to develop mild illness and who is going to develop severe illness, and because of that we have to take these infections very seriously,” Nuzzo says. “We should not assume that all future infections will be mild.”
There’s another clue that could explain the severity of the Louisiana and British Columbia cases. Virus samples from both patients showed some similarities. For one, both were infected with the same subtype of H5N1 called D1.1, which is the same kind of virus found in wild birds and poultry. It’s different from the B3.13 subtype, which is dominant in dairy cows.
“Right now, the question is, is this a more severe strain than the dairy cattle strain?” says Benjamin Anderson, assistant professor of environmental and global health at the University of Florida. So far, scientists don’t have enough data to know for sure. A handful of poultry farm workers in Washington have tested positive for the D1.1 subtype, but those individuals had mild symptoms and did not require hospitalization.
“In the case of the Louisiana infection, we know that person had comorbidities. We know that person was an older individual. These are factors that contribute to more severe outcomes already when it comes to respiratory infections,” Anderson says.
In the Louisiana and British Columbia cases, there’s evidence that the virus may have evolved in both patients to produce more severe illness.
A CDC report from late December found genetic mutations in the virus taken from the Louisiana patient that may have allowed it to enhance its ability to infect the upper airways of humans. The report says the changes observed were likely generated by replication of the virus throughout the patient’s illness rather than transmitted at the time of infection, meaning that the mutations weren’t present in the birds the person was exposed to.
Writing in the New England Journal of Medicine, the team that cared for the Canadian teen also described “worrisome” mutations found in her viral samples. These changes could have allowed the virus to more easily bind to and enter cells in the human respiratory tract.
In the past, bird flu has rarely been transmitted from person to person, but scientists worry about a scenario where the virus would acquire mutations that would make human transmission more likely.
For now, people who work with birds, poultry, or cows, or have recreational exposure to them, are at higher risk of getting bird flu. To prevent illness, health officials recommend avoiding direct contact with wild birds and other animals infected with or suspected to be infected with bird flu viruses.
Emily Mullin is a staff writer at WIRED, covering biotechnology. Previously, she was an MIT Knight Science Journalism project fellow and a staff writer covering biotechnology at Medium's OneZero. Before that, she served as an associate editor at MIT Technology Review, where she wrote about biomedicine. Her stories have also... Read more
Bird flu continues to spread widely in cattle and wild birds. What challenges does the incoming Trump administration face in tackling the outbreak and preparing for a possible pandemic?
The first confirmed death from the H5N1 bird flu in the U.S., reported Monday by officials in Louisiana, comes amid growing concerns that the world could be stumbling into another pandemic.
The bad news around the H5N1 outbreak has been mounting: Nearly a thousand U.S. dairy herds infected since last March, nearly 20 million domestic poultry destroyed due to infections in December, 66 human infections in the U.S., and now one death.
The first human death from bird flu in the United States has intensified calls for the government to ramp up efforts to stave off the threat of another pandemic -- particularly ahead of Donald Trump's return to the White House.
Health experts around the world have for months been urging US authorities to increase surveillance and share more information about its bird flu outbreak after the virus started spreading among dairy cows for the first time.
On Monday, Louisiana health authorities reported that a patient aged over 60 was the country's first person to die from bird flu.
The patient, who contracted avian influenza after being exposed to infected birds, had underlying medical conditions, US health authorities said.
The World Health Organization has maintained that bird flu's risk to the general population is low, and there is no evidence that it has been transmitted between people.
However health experts have been sounding the alarm about the potential pandemic threat of bird flu, particularly as it has shown signs of mutating in mammals into a form that could spread more easily among humans.
The avian influenza variant H5N1 was first detected in 1996, but a record global outbreak since 2020 has resulted in hundreds of millions of poultry birds being culled -- and killed an unknown but massive number of wild birds.
In March, the virus started transmitting between dairy cows in the United States.
Since the start of last year, 66 bird flu cases have been recorded in humans in the United States, many of them among farm workers, according to the Centers for Disease Control and Prevention.
The US cases had been relatively mild until the Louisiana patient, though a Canadian teenager become severely ill. Nearly half of the 954 human cases of H5N1 recorded since 2003 have been fatal, according to the WHO.
Marion Koopmans, a virologist at the Erasmus University Medical Center in the Netherlands, emphasised that the public should not be unduly worried about another pandemic.
"The problem is that this is how it could start," she added.
Koopmans criticised that "there is not really an effort to contain" the bird flu outbreak among cattle in the United States.
Tom Peacock, a virologist at the Imperial College London, said he thought "the biggest error the US has made is its slow and weak response to the cattle outbreak".
The reason bird flu was affecting US cattle seemed to be a combination of this weak early response, poor biosecurity, "and the intensification of US dairy farming (which involves far more movement of animals than any European system)," he told AFP.
Peacock was a co-author of a preprint study released on Monday, which has not been peer-reviewed, describing how the mutations of H5N1 in cattle enhance its ability to infect other mammals -- including humans.
Rebecca Christofferson, a scientist at Louisiana State University, said there were signs that the deceased patient's virus mutated while they were infected -- but it was not transmitted to anyone else.
"The worry is, the more you let this sort of run wild... the more chances you have for this sort of mutation to not only occur, but to then get out and infect someone else, then you start a chain reaction," she told AFP.
WHO spokeswoman Margaret Harris said the United States "are doing a lot of surveillance" on bird flu. "That's why we're hearing about it," she added.
Last week, the US government awarded an additional $306 million to bolster H5N1 surveillance programs and research.
Peacock said that monitoring has increased for US cattle but warned "big gaps" remain.
Rick Bright, a former top US health official, has been among those calling for the department of agriculture to release more information about bird flu infections among animals.
"There are still just reams of data from this current administration that haven't been released," he told the Washington Post on Monday.
The United States has a stockpile of millions of H5N1 vaccine doses, which Bright said should be offered to at-risk people such as farm workers.
The Biden government has also been urged to encourage companies to develop rapid home tests as well as monitor wastewater for bird flu.
Several of the experts called on Biden to act quickly, before president-elect Trump replaces him in less than two weeks.
There are particular concerns about Trump's pick for health secretary, Robert F. Kennedy Jr.
Kennedy is a sceptic of vaccines, which would be among the most powerful weapons to fend off a potential new pandemic. He is also a known fan of raw milk, which has repeatedly been found to be contaminated with bird flu from infected dairy cows.
People at home have been advised to avoid infected animals -- and raw milk -- and to get a seasonal flu vaccine.
Christofferson said her "biggest worry" was that if someone was infected with both seasonal flu and H5N1, they could mix to become "something that's either more transmissible and or more dangerous to people".
NEW YORK (AP) — The first U.S. bird flu death has been reported — a person in Louisiana who had been hospitalized with severe respiratory symptoms.
State health officials announced the death on Monday, and the Centers for Disease Control and Prevention confirmed it was the nation’s first due to bird flu.
Health officials have said the person was older than 65, had underlying medical problems and had been in contact with sick and dead birds in a backyard flock. They also said a genetic analysis had suggested the bird flu virus had mutated inside the patient, which could have led to the more severe illness.
Few other details about the person have been disclosed.
Since March, 66 confirmed bird flu infections have been reported in the U.S., but previous illnesses have been mild and most have been detected among farmworkers exposed to sick poultry or dairy cows.
A bird flu death was not unexpected, virus experts said. There have been more than 950 confirmed bird flu infections globally since 2003, and more than 460 of those people died, according to the World Health Organization.
The bird flu virus “is a serious threat and it has historically been a deadly virus,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health. “This is just a tragic reminder of that.”
Nuzzo noted a Canadian teen became severely ill after being infected recently. Researchers are still trying to gauge the dangers of the current version of the virus and determine what causes it to hit some people harder than others, she said.
“Just because we have seen mild cases does not mean future cases will continue to be mild,” she added.
In a statement, CDC officials described the Louisiana death as tragic but also said “there are no concerning virologic changes actively spreading in wild birds, poultry or cows that would raise the risk to human health.”
In two of the recent U.S. cases — an adult in Missouri and a child in California — health officials have not determined how they caught the virus. The origin of the Louisiana person’s infection was not considered a mystery. But it was the first human case in the U.S. linked to exposure to backyard birds, according to the CDC.
Louisiana officials say they are not aware of any other cases in their state, and U.S. officials have said they do not have any evidence that the virus is spreading from person to person.
The H5N1 bird flu has been spreading widely among wild birds, poultry, cows and other animals. Its growing presence in the environment increases the chances that people will be exposed, and potentially catch it, officials have said.
Officials continue to urge people who have contact with sick or dead birds to take precautions, including wearing respiratory and eye protection and gloves when handling poultry.
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The patient, aged over 65, had been hospitalized in the southern state since at least mid-December, when the US Centers for Disease Control and Prevention (CDC) announced it as the country's first serious case of human infection from the H5N1 virus.
"While the current public health risk for the general public remains low, people who work with birds, poultry or cows, or have recreational exposure to them, are at higher risk," the Louisiana Department of Health said in a statement announcing the death.
It said the patient had "contracted H5N1 after exposure to a combination of a non-commercial backyard flock and wild birds," but had detected no further H5N1 infections nor evidence of person-to-person transmission in the state.
The news comes just days after the federal government awarded an additional $306 million to bolster H5N1 surveillance programs and research, amid some criticism for President Joe Biden's administration over its response to the simmering issue.
The amount of bird flu circulating among animals and humans has alarmed scientists over concerns it could mutate into a more transmissible form -- potentially triggering a deadly pandemic.
Since the beginning the 2024, the CDC has recorded 66 cases of bird flu in humans in the United States.
"We have a lot of data that shows that this virus can be lethal, more lethal than many viruses we worry about," Jennifer Nuzzo, a professor of epidemiology at Brown University, told AFP.
"For that reason, people have been quite alarmed about these outbreaks that have been occurring on farms and other places in the US and have really been shouting for the US government to do more," she said.
Death 'not unexpected'
The CDC said in December that genetic sequencing of the H5N1 virus from the Louisiana patient was different from the version detected in many dairy herds around the country.
And a small part of the virus in the patient had genetic modifications that suggested it could have mutated inside the body to adapt to the human respiratory tract.
However, such mutations are not the only thing that could make the virus more contagious or transmissible between humans, according to researchers interviewed by AFP.
H5N1 was first detected in 1996, but since 2020, the number of outbreaks among bird flocks has exploded, while a growing number of mammal species have been affected.
"While tragic, a death from H5N1 bird flu in the United States is not unexpected because of the known potential for infection with these viruses to cause severe illness and death," the CDC said in a statement.
The World Health Organization has recorded over 950 bird flu cases in humans since 2003 in 24 countries, including a large number in China and Vietnam.
Nuzzo said the announcement of the US death did not change her perspective, but underscored her "big worry about the relatively unchecked spread of this virus and the urgency of doing more to prevent people from being infected."
"This is a nasty virus that no one wants to get," she said.