Amy Maxmen, KFF Health News

Sonya Stokes, an emergency room physician in the San Francisco Bay Area, braces herself for a daily deluge of patients sick with coughs, soreness, fevers, vomiting, and other flu-like symptoms.

She’s desperate for information, but the Centers for Disease Control and Prevention, a critical source of urgent analyses of the flu and other public health threats, has gone quiet in the weeks since President Donald Trump took office.

“Without more information, we are blind,” she said.

Flu has been brutal this season. The CDC estimates at least 24 million illnesses, 310,000 hospitalizations, and 13,000 deaths from the flu since the start of October. At the same time, the bird flu outbreak continues to infect cattle and farmworkers. But CDC analyses that would inform people about these situations are delayed, and the CDC has cut off communication with doctors, researchers, and the World Health Organization, say doctors and public health experts.

“CDC right now is not reporting influenza data through the WHO global platforms, FluNet [and] FluID, that they’ve been providing information [on] for many, many years,” Maria Van Kerkhove, interim director of epidemic and pandemic preparedness at the WHO, said at a Feb. 12 press briefing.

“We are communicating with them,” she added, “but we haven’t heard anything back.”

On his first day in office, President Donald Trump announced the U.S. would withdraw from the WHO.

A critical analysis of the seasonal flu selected for distribution through the CDC’s Health Alert Network has stalled, according to people close to the CDC. They asked not to be identified because of fears of retaliation. The network, abbreviated as HAN, is the CDC’s main method of sharing urgent public health information with health officials, doctors, and, sometimes, the public.

A chart from that analysis, reviewed by KFF Health News, suggests that flu may be at a record high. About 7.7% of patients who visited clinics and hospitals without being admitted had flu-like symptoms in early February, a ratio higher than in four other flu seasons depicted in the graph. That includes 2003-04, when an atypical strain of flu fueled a particularly treacherous season that killed at least 153 children.

Without a complete analysis, however, it’s unclear whether this tidal wave of sickness foreshadows a spike in hospitalizations and deaths that hospitals, pharmacies, and schools must prepare for. Specifically, other data could relay how many of the flu-like illnesses are caused by flu viruses — or which flu strain is infecting people. A deeper report might also reveal whether the flu is more severe or contagious than usual.

“I need to know if we are dealing with a more virulent strain or a coinfection with another virus that is making my patients sicker, and what to look for so that I know if my patients are in danger,” Stokes said. “Delays in data create dangerous situations on the front line.”

Although the CDC’s flu dashboard shows a surge of influenza, it doesn’t include all data needed to interpret the situation. Nor does it offer the tailored advice found in HAN alerts that tells health care workers how to protect patients and the public. In 2023, for example, a report urged clinics to test patients with respiratory symptoms rather than assume cases are the flu, since other viruses were causing similar issues that year.

“This is incredibly disturbing,” said Rachel Hardeman, a member of the Advisory Committee to the Director of the CDC. On Feb. 10, Hardeman and other committee members wrote to acting CDC Director Susan Monarez asking the agency to explain missing data, delayed studies, and potentially severe staff cuts. “The CDC is vital to our nation’s security,” the letter said.

Several studies have also been delayed or remain missing from the CDC’s preeminent scientific publication, the Morbidity and Mortality Weekly Report. Anne Schuchat, a former principal deputy director at the CDC, said she would be concerned if there was political oversight of scientific material: “Suppressing information is potentially confusing, possibly dangerous, and it can backfire.”

CDC spokesperson Melissa Dibble declined to comment on delayed or missing analyses. “It is not unexpected to see flu activity elevated and increasing at this time of the year,” she said.

A draft of one unpublished study, reviewed by KFF Health News, that has been withheld from the MMWR for three weeks describes how a milk hauler and a dairy worker in Michigan may have spread bird flu to their pet cats. The indoor cats became severely sick and died. Although the workers weren’t tested, the study says that one of them had irritated eyes before the cat fell ill — a common bird flu symptom. That person told researchers that the pet “would roll in their work clothes.”

After one cat became sick, the investigation reports, an adolescent in the household developed a cough. But the report says this young person tested negative for the flu, and positive for a cold-causing virus.

Corresponding CDC documents summarizing the cat study and another as-yet unpublished bird flu analysis said the reports were scheduled to be published Jan. 23. These were reviewed by KFF Health News. The briefing on cats advises dairy farmworkers to “remove clothing and footwear, and rinse off any animal biproduct residue before entering the household to protect others in the household, including potentially indoor-only cats.”

The second summary refers to “the most comprehensive” analysis of bird flu virus detected in wastewater in the United States.

Jennifer Nuzzo, director of the Pandemic Center at Brown University, said delays of bird flu reports are upsetting because they’re needed to inform the public about a worsening situation with many unknown elements. Citing “insufficient data” and “high uncertainty,” the United Kingdom raised its assessment of the risk posed by the U.S. outbreak on dairies.

“Missing and delayed data causes uncertainty,” Nuzzo said. “It also potentially makes us react in ways that are counterproductive.”

Another bird flu study slated for January publication showed up in the MMWR on Feb. 13, three weeks after it was expected. It revealed that three cattle veterinarians had been unknowingly infected last year, based on the discovery of antibodies against the bird flu virus in their blood. One of the veterinarians worked in Georgia and South Carolina, states that haven’t reported outbreaks on dairy farms.

The study provides further evidence that the United States is not adequately detecting cases in cows and people. Nuzzo said it also highlights how data can supply reassuring news. Only three of 150 cattle veterinarians had signs of prior infections, suggesting that the virus doesn’t easily spread from the animals into people. More than 40 dairy workers have been infected, but they generally have had more sustained contact with sick cattle and their virus-laden milk than veterinarians.

Instead, recently released reports have been about wildfires in California and Hawaii.

“Interesting but not urgent,” Nuzzo said, considering the acute fire emergencies have ended. The bird flu outbreak, she said, is an ongoing “urgent health threat for which we need up-to-the-minute information to know how to protect people.”

“The American public is at greater risk when we don’t have information on a timely basis,” Schuchat said.

This week, a federal judge ordered the CDC and other health agencies to “restore” datasets and websites that the organization Doctors for America had identified in a lawsuit as having been altered. Further, the judge ordered the agencies to “identify any other resources that DFA members rely on to provide medical care” and restore them by Feb. 14.

In their letter, CDC advisory committee members requested an investigation into missing data and delayed reports. Hardeman, an adviser who is a health policy expert at the University of Minnesota, said the group didn’t know why data and scientific findings were being withheld or removed. Still, she added, “I hold accountable the acting director of the CDC, the head of HHS, and the White House.”

Hardeman said the Trump administration has the power to disband the advisory committee. She said the group expects that to happen but proceeded with its demands regardless.

“We want to safeguard the rigor of the work at the CDC because we care deeply about public health,” she said. “We aren’t here to be silent.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.

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This article first appeared on KFF Health News and is republished here under a Creative Commons license.

It’s been nearly three months since the U.S. government announced an outbreak of the bird flu virus on dairy farms. The World Health Organization considers the virus a public health concern because of its potential to cause a pandemic, yet the U.S. has tested only about 45 people across the country.

“We’re flying blind,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health. With so few tests run, she said, it’s impossible to know how many farmworkers have been infected, or how serious the disease is. A lack of testing means the country might not notice if the virus begins to spread between people — the gateway to another pandemic.

“We’d like to be doing more testing. There’s no doubt about that,” said Nirav Shah, principal deputy director of the Centers for Disease Control and Prevention. The CDC’s bird flu test is the only one the Food and Drug Administration has authorized for use right now. Shah said the agency has distributed these tests to about 100 public health labs in states. “We’ve got roughly a million available now,” he said, “and expect 1.2 million more in the next two months.”

But Nuzzo and other researchers are concerned because the CDC and public health labs aren’t generally where doctors order tests from. That job tends to be done by major clinical laboratories run by companies and universities, which lack authorization for bird flu testing.

As the outbreak grows — with at least 114 herds infected in 12 states as of June 18 — researchers said the CDC and FDA are not moving fast enough to remove barriers that block clinical labs from testing. In one case, the diagnostics company Neelyx Labs was on hold with a query for more than a month.

“Clinical labs are part of the nation’s public health system,” said Alex Greninger, assistant director of the University of Washington Medicine Clinical Virology Laboratory. “Pull us into the game. We’re stuck on the bench.”

The CDC recognized the need for clinical labs in a June 10 memo. It calls on industry to develop tests for the H5 strain of bird flu virus, the one circulating among dairy cattle. “The limited availability and accessibility of diagnostic tests for Influenza A(H5) poses several pain points,” the CDC wrote. The points include a shortage of tests if demand spikes.

Researchers, including former CDC director Tom Frieden and Anthony Fauci, who led the nation’s response to covid, cite testing failures as a key reason the U.S. fared so poorly with covid. Had covid tests been widely available in early 2020, they say, the U.S. could have detected many cases before they turned into outbreaks that prompted business shutdowns and cost lives.

In an article published this month, Nuzzo and a group of colleagues noted that the problem wasn’t testing capability but a failure to deploy that capability swiftly. The U.S. reported excess mortality eight times as high as other countries with advanced labs and other technological advantages.

A covid test vetted by the WHO was available by mid-January 2020. Rather than use it, the United States stuck to its own multistage process, which took several months. Namely, the CDC develops its own test then sends it to local public health labs. Eventually, the FDA authorizes tests from clinical diagnostic labs that serve hospital systems, which must then scale up their operations. That took time, and people died amid outbreaks at nursing homes and prisons, waiting on test results.

In contrast, South Korea immediately rolled out testing through private sector laboratories, allowing it to keep schools and businesses open. “They said, ‘Gear up, guys; we’re going to need a ton of tests,’” said Frieden, now president of the public health organization Resolve to Save Lives. “You need to get commercials in the game.”

Nuzzo and her colleagues describe a step-by-step strategy for rolling out testing in health emergencies, in response to mistakes made obvious by covid. But in this bird flu outbreak, the U.S. is weeks behind that playbook.

Ample testing is critical for two reasons. First, people need to know if they’re infected so that they can be quickly treated, Nuzzo said. Over the past two decades, roughly half of about 900 people around the globe known to have gotten the bird flu died from it.

Although the three farmworkers diagnosed with the disease this year in the United States had only mild symptoms, like a runny nose and inflamed eyes, others may not be so lucky. The flu treatment Tamiflu works only when given soon after symptoms start.

The CDC and local health departments have tried to boost bird flu testing among farmworkers, asking them to be tested if they feel sick. Farmworker advocates list several reasons why their outreach efforts are failing. The outreach might not be in the languages the farmworkers speak, for example, or address such concerns as a loss of employment.

If people who live and work around farms simply see a doctor when they or their children fall ill, those cases could be missed if the doctors send samples to their usual clinical laboratories. The CDC has asked doctors to send samples from people with flu symptoms who have exposure to livestock or poultry to public health labs. “If you work on a farm with an outbreak and you’re worried about your welfare, you can get tested,” Shah said. But sending samples to public health departments requires knowledge, time, and effort.

“I really worry about a testing scheme in which busy clinicians need to figure this out,” Nuzzo said.

The other reason to involve clinical laboratories is so the nation can ramp up testing if the bird flu is suddenly detected among people who didn’t catch it from cattle. There’s no evidence the virus has started to spread among people, but that could change in coming months as it evolves.

The fastest way to get clinical labs involved, Greninger said, is to allow them to use a test the FDA has already authorized: the CDC’s bird flu test. On April 16 the CDC opened up that possibility by offering royalty-free licenses for components of its bird flu tests to accredited labs.

Several commercial labs asked for licenses. “We want to get prepared before things get crazy,” said Shyam Saladi, chief executive officer of the diagnostics company Neelyx Labs, which offered covid and mpox tests during shortages in those outbreaks. His experience over the past two months reveals the types of barriers that prevent labs from moving swiftly.

In email exchanges with the CDC, shared with KFF Health News, Saladi specifies the labs’ desire for licenses relevant to the CDC’s test, as well as a “right to reference” the CDC’s data in its application for FDA authorization.

That “right to reference” makes it easier for one company to use a test developed by another. It allows the new group to skip certain analyses conducted by the original maker, by telling the FDA to look at data in the original FDA application. This was commonplace with covid tests at the peak of the pandemic.

At first, the CDC appeared eager to cooperate. “A right of reference to the data should be available,” Jonathan Motley, a patent specialist at the CDC, wrote in an email to Saladi on April 24. Over the next few weeks, the CDC sent him information about transferring its licenses to the company, and about the test, which prompted Neelyx’s researchers to buy testing components and try out the CDC’s process on their equipment.

But Saladi grew increasingly anxious about the ability to reference the CDC’s data in the company’s FDA application. “Do you have an update with respect to the right of reference?” he asked the CDC on May 13. “If there are any potential sticking points with respect to this, would you mind letting us know please?”

He asked several more times in the following weeks, as the number of herds infected with the bird flu ticked upward and more cases among farmworkers were announced. “Given that it is May 24 and the outbreak has only expanded, can CDC provide a date by which it plans to respond?” Saladi wrote.

The CDC eventually signed a licensing agreement with Neelyx but informed Saladi that it would not, in fact, provide the reference. Without that, Saladi said, he could not move forward with the CDC’s test — at least not without more material from the agency. “It’s really frustrating,” he said. “We thought they really intended to support the development of these tests in case they are needed.”

Shah, from the CDC, said test manufacturers should generate their own data to prove that they’re using the CDC’s test correctly. “We don’t have a shortage such that we need to cut corners,” he said. “Quality reigns supreme.”

The CDC has given seven companies, including Neelyx, licenses for its tests — although none have been cleared to use them by the FDA. Only one of those companies asked for the right of reference, Shah said. The labs may be assisted by additional material that the agency is developing now, to allow them to complete the analyses — even without the reference.

“This should have happened sooner,” Saladi told KFF Health News when he was told about the CDC’s pending additional material. “There’s been no communication about this.”

Greninger said the delays and confusion are reminiscent of the early months of covid, when federal agencies prioritized caution over speed. Test accuracy is important, he said, but excessive vetting can cause harm in a fast-moving outbreak like this one. “The CDC should be trying to open this up to labs with national reach and a good reputation,” he said. “I fall on the side of allowing labs to get ready — that’s a no-brainer.”

Clinical laboratories have also begun to develop their own tests from scratch. But researchers said they’re moving cautiously because of a recent FDA rule that gives the agency more oversight of lab-developed tests, lengthening the pathway to approval. In an email to KFF Health News, FDA press officer Janell Goodwin said the rule’s enforcement will occur gradually.

However, Susan Van Meter, president of the American Clinical Laboratory Association, a trade group whose members include the nation’s largest commercial diagnostic labs, said companies need more clarity: “It’s slowing things down because it’s adding to the confusion about what is allowable.”

Creating tests for the bird flu is already a risky bet, because demand is uncertain. It’s not clear whether this outbreak in cattle will trigger an epidemic or fizzle out. In addition to issues with the CDC and FDA, clinical laboratories are trying to figure out whether health insurers or the government will pay for bird flu tests.

These wrinkles will be smoothed eventually. Until then, the vanishingly slim numbers of people tested, along with the lack of testing in cattle, may draw criticism from other parts of the world.

“Think about our judgment of China’s transparency at the start of covid,” Nuzzo said. “The current situation undermines America’s standing in the world.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF — an independent source of health policy research, polling, and journalism. Learn more about KFF. Subscribe to KFF Health News' free Morning Briefing.