A federal vaccine panel entirely hand-selected by health secretary and anti-vaccine activist Robert F. Kennedy Jr. gathered for its first meeting Wednesday—and immediately announced that it would re-evaluate the entire childhood vaccination schedule, as well as the one for adults.
The meeting overall was packed with anti-vaccine talking points and arguments from the new panel members, confirming public health experts’ fears that the once-revered panel is now critically corrupted and that Kennedy’s controversial picks will only work to fulfill his long-standing anti-vaccine agenda.
Controversial committee
An hour before the meeting began, the American Academy of Pediatrics came out swinging against the new panel, saying that the panel’s work is “no longer a credible process.” The organization shunned the meeting, refusing to send a liaison to the panel’s meeting, which it has done for decades.
“We won’t lend our name or our expertise to a system that is being politicized at the expense of children’s health,” AAP President Susan Kressly said in a video posted on social media.
The panel in question, the Advisory Committee on Immunization Practices (ACIP), has for more than 60 years provided rigorous public scientific review, discussion, and trusted recommendations to the Centers for Disease Control and Prevention on how vaccines should be used in the US after they’ve earned approval from the Food and Drug Administration. The CDC typically adopts ACIP’s recommendations, and once that happens, insurance providers are required to cover the cost of the recommended shots.
The system is highly regarded globally. But, on June 9, Kennedy unilaterally and summarily fired all 17 esteemed ACIP members and, two days later, replaced them with eight new people. Some have clear anti-vaccine views, others have controversial and contrarian public health views, and several have little to no expertise in the fields relevant to vaccines.
Last night, it came to light that one of the eight new appointees—Michael Ross, an obstetrics and gynecology physician—had withdrawn from the committee during a financial holdings review that ACIP members are required to complete before beginning work on the panel.
The Department of Health and Human Services—under the control of anti-vaccine advocate Robert F. Kennedy Jr.—has canceled millions of dollars in federal funding awarded to Moderna to produce an mRNA vaccine against influenza viruses with pandemic potential, including the H5N1 bird flu currently sweeping US poultry and dairy cows.
Last July, the Biden administration’s HHS awarded Moderna $176 million to “accelerate the development of mRNA-based pandemic influenza vaccines.” In the administration’s final days in January, HHS awarded the vaccine maker an additional $590 million to support “late-stage development and licensure of pre-pandemic mRNA-based vaccines.” The funding would also go to the development of five additional subtypes of pandemic influenza.
On Wednesday, as news broke that the Trump administration was reneging on the contract, Moderna reported positive results from an early trial of a vaccine targeting H5 influenza viruses. In a preliminary trial of 300 healthy adults, the vaccine candidate appeared safe and boosted antibody levels against the virus by 44.5-fold.
An HHS spokesperson said that the decision to cancel the funding—which would support thorough safety and efficacy testing of the vaccines—was because the vaccines needed more testing.
“This is not simply about efficacy—it’s about safety, integrity, and trust.” HHS spokesperson Andrew Nixon told The Washington Post. “The reality is that mRNA technology remains under-tested.”
Nixon went on to claim that the Trump administration wouldn’t repeat the “mistakes of the last administration, which concealed legitimate safety concerns.” The accusation refers to mRNA-based COVID-19 vaccines, which were developed and initially released under the first Trump administration. They have since been proven safe and effective against the deadly virus.
The milk-related risk of H5N1 is only from raw milk; pasteurized milk does not contain live virus and is safe to drink. Pasteurization, which heats milk to a specific temperature for a specified amount of time, kills a variety of bacteria and viruses, including bird flu. Influenza viruses, generally, are considered susceptible to heat treatments because they have an outer layer called an envelope, which can be destabilized by heat. Studies that have specifically looked at the effectiveness of heat-killing treatments against H5N1 have repeatedly found that pasteurization effectively inactivates the virus.
The advent of pasteurization is considered a public health triumph. Its adoption of a safe milk supply contributed to a dramatic reduction in infant deaths in the early 20th century. Before that, milkborne infections—including human and bovine tuberculosis, brucellosis, salmonellosis, streptococcal infections, diphtheria, and “summer diarrhea”—were common killers of infants.
As such, public health officials have long advised people against consuming raw milk, which has no evidence-based health benefits. Raw milk consumption, meanwhile, is linked to higher rates of outbreaks from pathogens including Salmonella, Listeria monocytogenes, toxin-producing E. coli, Brucella, Campylobacter, and many other bacteria.
Risky drinking
Since H5N1 was found spreading among dairy cows in March, health experts have warned about the additional risk of consuming raw milk. Still, consumption of raw milk has continued, and surprisingly increased, as supporters of the dangerous practice have accused health officials of “fearmongering.”
When the retail sampling of Raw Farm’s milk came back positive, the California Department of Food and Agriculture (CDFA) conducted testing at the company’s locations, which were negative for the virus. The CDFA will now begin testing Raw Farm’s milk for bird flu twice a week.
The recalled milk has lot code 20241109 and a “best by” date of November 27, 2024, printed on the packaging.
“Drinking or accidentally inhaling raw milk containing bird flu virus may lead to illness,” California’s public health department said. “In addition, touching your eyes, nose, or mouth with unwashed hands after touching raw milk with bird flu virus may also lead to infection.”
Some US dairy workers who contracted the virus from infected cows reported having had milk splash in their eyes and face. A common symptom of H5N1 infections in humans during the dairy outbreak has been conjunctivitis, aka eye inflammation.
So, in all, Missouri’s case count in the H5N1 outbreak will stay at one for now, and there remains no evidence of human-to-human transmission. Though both the household contact and the index case had evidence of an exposure, their identical blood test results and simultaneous symptom development suggest that they were exposed at the same time by a single source—what that source was, we may never know.
California and Washington
While the virus seems to have hit a dead end in Missouri, it’s still running rampant in California. Since state officials announced the first dairy herd infections at the end of August, the state has now tallied 137 infected herds and at least 13 infected dairy farm workers. California, the country’s largest dairy producer, now has the most herd infections and human cases in the outbreak, which was first confirmed in March.
In the briefing Thursday, officials announced another front in the bird flu fight. A chicken farm in Washington state with about 800,000 birds became infected with a different strain of H5 bird flu than the one circulating among dairy farms. This strain likely came from wild birds. While the chickens on the infected farms were being culled, the virus spread to farmworkers. So far, two workers have been confirmed to be infected, and five others are presumed to be positive.
As of publication time, at least 31 humans have been confirmed infected with H5 bird flu this year.
With the spread of bird flu in dairies and the fall bird migration underway, the virus will continue to have opportunities to jump to mammals and gain access to people. Officials have also expressed anxiety as seasonal flu ramps up, given influenza’s penchant for swapping genetic fragments to generate new viral combinations. The reassortment and exposure to humans increases the risk of the virus adapting to spread from human to human and spark an outbreak.
Enlarge/ A warning sign outside a laboratory testing the H5N1 bird flu virus at The Pirbright Institute in Woking, UK, on Monday, March 13, 2023.
More than a month after a person in Missouri mysteriously fell ill with H5-type bird flu, investigators in the state are still identifying people who became ill after contact with the patient, raising questions about the diligence of the ongoing health investigation.
On September 6, Missouri’s health department reported the state’s first human case of H5-type bird flu, one that appears closely related to the H5N1 bird flu currently causing a nationwide outbreak among dairy cows. But the infected person had no known contact with infected animals—unlike all of the other 13 human cases identified amid the dairy outbreak this year. Those previous cases have all occurred in dairy- or poultry-farm workers. In fact, Missouri has not reported bird flu in its dairy herds nor recent poultry outbreaks.
Given the unexplained source of infection, health investigators in the state have been working to track the virus both backward in time—to try to identify the source—and forward—to identify any potential onward spread. The bird flu patient was initially hospitalized on August 22 but recovered and had been released by the time the state publicly reported the case.
In an update Friday, September 27, the Centers for Disease Control and Prevention relayed that Missouri officials have now identified four more health care workers who experienced mild respiratory illnesses after caring for the person with bird flu. None of the four workers were tested for flu at the time of their illnesses and all have since recovered.
Testing new cases for antibodies to H5N1
The four newly identified cases bring the total number of health care workers who fell ill after contact to six. Missouri investigators had previously identified two other health care workers who developed mild respiratory symptoms. One of those workers was tested for flu around the time of their illness—and tested negative. But the other, like the four newly identified cases, was not tested. That person has since submitted a blood sample to test for bird flu antibodies, which would indicate a previous infection.
In addition, a household contact of the bird flu patient also fell ill at the same time as the patient, suggesting a possible common source of the infection.
The illnesses are concerning, given the fear that H5N1 bird flu could begin spreading from human to human and spark a widespread outbreak or even a pandemic. However, it can’t be overlooked that a plethora of other respiratory viruses are around—and SARS-CoV-2 transmission was relatively high in Missouri at the time—it’s impossible to draw any conclusions at this point about whether the illnesses were bird flu infections.
But, the illnesses do clearly raise concern about the health investigation, which is being conducted by Missouri officials. “The slow trickle of info is the most concerning part,” infectious disease expert Krutika Kuppalli wrote on social media Friday. The CDC can get involved at the request of a state, but such a request has not been made. For now, the CDC is only providing technical assistance from Atlanta.
In its update today, the CDC emphasized that “to date, only one case of influenza A(H5N1) has been detected in Missouri. No contacts of that case have tested positive for influenza A(H5N1).” The agency added that blood testing results for H5 antibodies are pending.
MDHSS reported that the person, who has underlying medical conditions, was hospitalized on August 22 and tested positive for an influenza A virus. Further testing at the state’s public health laboratory indicated that the influenza A virus was an H5-type bird flu. The Centers for Disease Control and Prevention has now confirmed that finding and is carrying out further testing to determine if it is the H5N1 strain currently causing a widespread outbreak among US dairy cows.
It remains unclear if the person’s bird flu infection was the cause of the hospitalization or if the infection was discovered incidentally. The person has since recovered and was discharged from the hospital. In its announcement, MDHSS said no other information about the patient will be released to protect the person’s privacy.
The report marks the 15th human case of an H5-type bird flu infection in the country since 2022. But, the case stands out—and is quickly generating alarm online—because the man reported no contact with animals. All 14 of the previous cases occurred in farmworkers who had contact with either dairy cows or poultry that were known to be infected with H5N1.
The finding in a person without such an exposure raises the possibility that the H5N1 virus is spreading from person to person, undetected, or is spreading via an undetected animal source.
But, while the case raises concern, some infectious disease experts are cautious not to sound the alarm without more data on the case and potential exposures.
“[U]ntil such data is collected and analyzed, my level of alarm is only mildly heightened,” Caitlin Rivers, a senior scholar at the Johns Hopkins Center for Health Security and founding associate director of the Center for Forecasting and Outbreak Analytics at the CDC, said online.
“I am encouraged that this case was detected through existing surveillance systems, which bodes well for our ability to identify any additional cases in the future,” she added. “Federal, state, and local health officials maintained flu surveillance through the summer months in response to the H5 situation, and that was definitely the right move.”
But Rivers, like many of her colleagues, has long worried about H5N1’s potential to jump to humans and spark a pandemic.
The highly pathogenic avian influenza H5N1 virus that spilled from wild birds into US dairy cows late last year may have recently seeped from a dairy farm in Colorado to a nearby poultry farm, where it then infected five workers tasked with culling the infected chickens
In a press briefing Tuesday, federal officials reported that four of the avian influenza cases have been confirmed by the Centers for Disease Control and Prevention, while the fifth remains a presumptive positive awaiting CDC confirmation.
All five people have shown mild illnesses, though they experienced variable symptoms. Some of the cases involved conjunctivitis, as was seen in other human cases linked to the H5N1 outbreak in dairy cows. Others in the cluster of five had respiratory and typical flu-like symptoms, including fever, chills, sore throat, runny nose, and cough. None of the five cases required hospitalization.
The virus infecting the five people is closely related to the virus infecting the chickens on the poultry farm, which, in turn, is closely related to virus seen in infected dairy herds and in other human cases that have been linked to the dairy outbreak. The affected poultry farm is in Colorado’s northern county of Weld, which has also reported about two dozen outbreaks of avian influenza in dairy herds.
Dairy to poultry hypothesis
In one fell swoop, Colorado’s poultry farm outbreak has more than doubled the number of human avian influenza cases linked to the dairy cow spillover, bringing the previous tally of four cases to nine. While officials have previously noted instances where it appeared that H5N1 on dairy farms had moved to nearby poultry farms, this appears to be the first time such spread has led to documented human infections.
The link between the poultry farm cases and neighboring dairy farms is still just a hypothesis, however, Nirav Shah, the principal deputy director at the CDC, emphasized to reporters Tuesday. “It is a hypothesis that needs and requires a full investigation. But that is a hypothesis at this point,” he said of the link between the dairy farms and the poultry farm. So far, there is no direct evidence of a specific source of the poultry farm’s infection, and the route of infection is also unclear.
Throughout the outbreak of H5N1 on dairy farms, officials have noted that the primary way the virus appears to spread to new farms is via the movement of cows, people, and machinery between those facilities. There remains no evidence of human-to-human transmission. But milk from infected cows has been found to be brimming with high levels of infectious virus, and milk-contaminated equipment is a prime suspect in the spread.
In the press briefing Tuesday, Eric Deeble, acting senior advisor for H5N1 response with the US Department of Agriculture, noted the poultry are very susceptible to avian influenza and are easily infected. “It does not take much to introduce this into a flock,” Deeble said. The USDA is now working on a “trace-back” investigation on how the Colorado poultry farm was infected.
Searing spread
As for how the farm workers specifically became infected with the virus, health officials pointed to high temperatures that prevented workers from donning protective gear. The poultry farm is a commercial egg layer operation with around 1.8 million birds. Given the presence of bird flu on the premises, all 1.8 million birds need to be culled, aka “depopulated.” This is being carried out using mobile carts with carbon dioxide gas chambers, a common culling method. Workers are tasked with placing the birds in the chambers, which only hold a few dozen birds at a time. In all, the method requires workers to have a high degree of contact with the infected birds, going from bird to bird and batch to batch with the carts.
Amid this grim task, temperatures in the area reached over 100° Fahrenheit, and massive industrial fans were turned on in the facility to try to cool things down. Between the heat and the fans, the approximately 160 people involved in the culling struggled to use personal protective equipment (PPE). The required PPE for the depopulation involves a full Tyvek suit, boots, gloves, goggles, and an N95 respirator.
“The difficulty with wearing all that gear in that kind of heat, you can imagine,” said Julie Gauthier, executive director for field operations at the USDA’s Animal and Plant Health Inspection Service (APHIS). The industrial fans blowing large amounts of air made it yet more difficult for workers to keep goggles and respirators on their faces, she said.
The CDC and the USDA are both involved in further investigations of the poultry farm outbreak. CDC’s Shah noted that the team the agency deployed to Colorado included an industrial hygienist, who can work on strategies to prevent further transmission.
To date, at least 161 herds in 13 states have tested positive for avian influenza since the dairy outbreak was confirmed in March. Since January 2022, when US birds first tested positive for the H5N1 virus, 99 million birds in the US have been affected in 48 states, which involved 1,165 individual outbreaks.
The US government will pay Moderna $176 million to develop an mRNA vaccine against a pandemic influenza—an award given as the highly pathogenic bird flu virus H5N1 continues to spread widely among US dairy cattle.
The funding flows through BARDA, the Biomedical Advanced Research and Development Authority, as part of a new Rapid Response Partnership Vehicle (RRPV) Consortium. The program is intended to set up partnerships with industry to help the country better prepare for pandemic threats and develop medical countermeasures, the Department of Health and Human Services said in a press announcement Tuesday.
In an announcement of its own Tuesday, Moderna noted that it began a Phase 1/2 trial of a pandemic influenza virus vaccine last year, which included versions targeting H5 and H7 varieties of bird flu viruses. The company said it expects to release the results of that trial this year and that those results will direct the design of a Phase 3 trial, anticipated to begin in 2025.
The funding deal will support late-stage development of a “pre-pandemic vaccine against H5 influenza virus,” Moderna said. But, the deal also includes options for additional vaccine development in case other public health threats arise.
“mRNA vaccine technology offers advantages in efficacy, speed of development, and production scalability and reliability in addressing infectious disease outbreaks, as demonstrated during the COVID-19 pandemic,” Moderna CEO Stéphane Bancel said in the announcement. “We are pleased to continue our collaboration with BARDA to expedite our development efforts for mRNA-based pandemic influenza vaccines and support the global public health community in preparedness against potential outbreaks.”
US health officials have said previously that they were in talks with Moderna and Pfizer about the development of a pandemic bird flu vaccine. The future vaccine will be in addition to standard protein-based bird flu vaccines that are already developed. In recent weeks, the health department has said it is working to manufacture 4.8 million vials of H5 influenza vaccine in the coming months. The plans come three months into the H5N1 dairy outbreak, which is very far from the initial hopes of containment.
Botched response
The US is badly fumbling its response to the unprecedented outbreak, drawing criticism from US-based and international experts alike. Genetic analyses suggest that the virus has been spreading among the country’s dairy cattle since late last year. But, it wasn’t until months later, on March 25, that the US Department of Agriculture confirmed the first four infected herds in two states (Texas and Kansas). Since then, the outbreak has spread to around 140 herds in 12 states—at least.
Some farms are refusing to test, and experts expect that there is a significant number of undocumented herd infections, particularly given the widespread detection of inactivated H5N1 in the commercial milk supply. Further, of the 140 herds with documented infections, federal officials do not know how many are still actively infected rather than recovered. It is unclear if infected cows can become reinfected, and if so, how quickly after an infection.
While the risk to the general public is considered to be low currently, farm workers are at higher risk of contracting the infection. To date, there have been three confirmed infections among dairy farm workers—one in Texas and two in Michigan, which has had a uniquely robust response to the outbreak. Still, with hundreds to thousands of farm workers at risk of contracting the virus, only 53 people in the country to date have been tested for H5 influenza.
In a presentation in London last month, global health leader Seth Berkley said it was “shocking to watch the ineptitude” of the US response to the H5N1 outbreak. He, like other experts, questioned whether the US public health community has learned or improved from the failures of the COVID-19 pandemic.
Similar to problems during the pandemic, a key barrier to the H5N1 response is resistance from farmers and farm workers to partner with state and federal health officials. Federal agencies have limited authority within states, but they have announced an array of assistance programs for dairy farms, including compensatory funding and access to personal protective equipment for farm workers. They have also issued guidance and restrictions to tighten biosecurity measures. But there has been little voluntary participation on both fronts.
For instance, officials figured out early in the outbreak that movement of cattle, workers, and equipment between farms is the main way H5N1 is spreading among dairies. In April, the USDA required testing of a portion of cows prior to their movement across state lines. But movement within states is governed by states. In a survey last month, which captured data from 54 percent of affected farms at the time, more than 60 percent of farmers said they continued to move cattle off their infected farms after the onset of clinical signs of infection in their animals.
The more the virus expands its footprint across US dairy farms, adapts to its newfound mammalian host, and comes in contact with humans, the more and more chances it has to leap to humans and gain the ability to spread among us.
In HHS’s Tuesday announcement of the Moderna award, Dawn O’Connell, assistant secretary for Preparedness and Response, spoke to the growing concern that the H5N1 outbreak could spark another pandemic. “The award made today is part of our longstanding commitment to strengthen our preparedness for pandemic influenza,” O’Connell said. “Adding this technology to our pandemic flu toolkit enhances our ability to be nimble and quick against the circulating strains and their potential variants.”
The US government is nearing an agreement to bankroll a late-stage trial of Moderna’s mRNA pandemic bird flu vaccine, hoping to bolster its pandemic jab stockpile as an H5N1 outbreak spreads through egg farms and among cattle herds.
The federal funding from the government’s Biomedical Advanced Research and Development Authority, known as BARDA, could come as early as next month, according to people close to the discussions.
It is expected to total several tens of millions of dollars and could be accompanied by a commitment to procure doses if the phase-three trials are successful, they said.
Talks between the government and Pfizer over supporting the development of its mRNA vaccine targeting the H5 family of viruses are also ongoing. Pfizer, like Moderna, played a pivotal role in supplying mRNA vaccines for Washington’s jab rollout during the COVID-19 pandemic.
Bird flu has been detected on poultry farms in 48 states and in dairy cow herds across nine states as part of one of the worst outbreaks in recent history, according to the US Centers for Disease Control and Prevention. The CDC has also reported two cases affecting dairy workers in recent months, adding to concerns of the virus spreading in human populations.
US health authorities continue to classify the public health risk from bird flu as low, but their efforts to build up and diversify the pandemic vaccine stockpile have gathered pace. Federal health officials said last week that the government was moving ahead with plans to fill 4.8 million vials from its existing portfolio of protein-based bird flu vaccines and was in discussions with Moderna and Pfizer.
The possibility of contributing to the US pandemic vaccine stockpile also represents a commercial opportunity for the mRNA vaccine makers, whose market valuations have fallen significantly from pandemic highs. Moderna’s share price is up nearly 37 percent since the start of April.
Moderna has completed dosing of a mid-stage trial of its H5 pandemic flu vaccine, with interim data expected soon. Pfizer said in a statement on Wednesday that it “would be prepared to deploy the company’s capabilities to develop a vaccine for strategic stockpiles,” confirming that it had launched a phase-one trial for a pandemic flu vaccine last December.
Applications for BARDA grant funding for an mRNA-based pandemic flu vaccine closed in December last year, according to a project proposal seen by the Financial Times. But the bird flu outbreak has increased the urgency of talks, with federal officials acknowledging that the speed with which mRNA vaccines were designed and deployed during the COVID-19 pandemic showed their value compared with more traditional vaccine technology.
The jabs from GSK, Sanofi, and CSL Seqirus, which make up the US government’s existing pandemic vaccine portfolio, provide immunity to the current strain of bird flu, according to laboratory testing, but rely on a more time-intensive manufacturing process using egg- and cell-based cultures.
The US health department, Moderna, and Pfizer declined to comment on the potential funding.
Enlarge/ Farm cats drinking from a trough of milk from cows that were just milked.
On March 16, cows on a Texas dairy farm began showing symptoms of a mysterious illness now known to be H5N1 bird flu. Their symptoms were nondescript, but their milk production dramatically dropped and turned thick and creamy yellow. The next day, cats on the farm that had consumed some of the raw milk from the sick cows also became ill. While the cows would go on to largely recover, the cats weren’t so lucky. They developed depressed mental states, stiff body movements, loss of coordination, circling, copious discharge from their eyes and noses, and blindness. By March 20, over half of the farm’s 24 or so cats died from the flu.
In a study published today in the journal Emerging Infectious Diseases, researchers in Iowa, Texas, and Kansas found that the cats had H5N1 not just in their lungs but also in their brains, hearts, and eyes. The findings are similar to those seen in cats that were experimentally infected with H5N1, aka highly pathogenic avian influenza virus (HPAI). But, on the Texas dairy farm, they present an ominous warning of the potential for transmission of this dangerous and evolving virus.
The contaminated milk was the most likely source of the cat’s fatal infections, the study authors concluded. Although it can’t be entirely ruled out that the cats got sick from eating infected wild birds, the milk they drank from the sick cows was brimming with virus particles, and genetic data shows almost exact matches between the cows, their milk, and the cats. “Therefore, our findings suggest cross-species mammal-to-mammal transmission of HPAI H5N1 virus and raise new concerns regarding the potential for virus spread within mammal populations,” wrote the authors, who are veterinary researchers from Iowa, Texas, and Kansas.
The early outbreak data from the Texas farm suggests the virus is getting better and better at jumping to mammals, and data from elsewhere shows the virus is spreading widely in its newest host. On March 25, the US Department of Agriculture confirmed the presence of H5N1 in a dairy herd in Texas, marking the first time H5N1 had ever been known to cross over to cows. Since then, the USDA has tallied infections in at least 34 herds in nine states: Texas, Kansas, Michigan, New Mexico, Idaho, Ohio, South Dakota, North Carolina, and Colorado.
Cows are only the latest addition to H5N1’s surprisingly broad host range. Amid a global outbreak over the past several years that has devastated wild bird populations and poultry farms, researchers have documented unexpected and often deadly outbreaks in mammals. Since 2022, the USDA has found H5N1 in over 200 mammals, from big cats in zoos to harbor seals, mountain lions, raccoons, skunks, squirrels, polar bears, black bears, foxes, and bottlenose dolphins.
“The recurring nature of global HPAI H5N1 virus outbreaks and detection of spillover events in a broad host range is concerning and suggests increasing virus adaptation in mammals,” the authors wrote. “Surveillance of HPAI viruses in domestic production animals, including cattle, is needed to elucidate influenza virus evolution and ecology and prevent cross-species transmission.”
In the meantime, it’s definitely not the time to start drinking raw cow’s milk. While drinking raw milk is always dangerous because it carries the threat of various nasty bacterial infections, H5N1 also appears to be infectious in raw milk. And, unlike other influenza viruses, H5N1 has the potential to infect organs beyond the lungs and respiratory tract, as seen in the cats. The authors of the new study note that a 2019 consumer survey found that 4.4 percent of adults in the US consumed raw milk more than once in the previous year, suggesting more public awareness of the dangers of raw milk is necessary.
The Food and Drug Administration on Tuesday announced that genetic fragments from the highly-pathogenic avian influenza virus H5N1 have been detected in the pasteurized, commercial milk supply. However, the testing completed so far—using quantitative polymerase chain reaction (qPCR)—only detects the presence of viral genetic material and cannot tell whether the genetic material is from live and infectious viral particles or merely remnants of dead ones killed by the pasteurization process.
Testing is now ongoing to see if viable, infectious H5N1 can be identified in milk samples.
So far, the FDA still believes that the milk supply is safe. “To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the agency said in a lengthy explanation of the finding and ongoing testing.
H5N1 made its startling jump to US dairy cows recently, with the first ever documented cases in a Texas herd confirmed on March 25. It has spread widely since then with at least 32 herds in eight states now known to be infected. The unexpected spread to bovines has raised fears that the virus is evolving to infect mammals more efficiently, and so poses a heightened risk of spread to and among humans.
But amid the alarming outbreak among the country’s dairy herds, federal agencies have appeared confident that the virus poses little risk to no risk to the safety of the milk supply.
“At this time, there continues to be no concern that this circumstance poses a risk to consumer health, or that it affects the safety of the interstate commercial milk supply because products are pasteurized before entering the market” the FDA wrote in an FAQ published Friday. “Pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk.”
In the announcement Tuesday, the FDA also highlighted that multiple studies have shown that the pasteurization process for eggs, which uses lower temperatures than what is used for milk, is effective at inactivating H5N1.
Nevertheless, the FDA, along with the Centers for Disease Control and Prevention and the US Department of Agriculture, have continued to investigate potential risks, including establishing whether pasteurization can inactivate this specific virus. The FDA noted in its announcement Tuesday that, while pasteurization is expected to kill the virus, pasteurization is “different than complete sterilization.”
As such, it carried out the qPCR tests, expecting it might find some genetic fragments in the pasteurized milk because virus has been detected in raw milk. “Based on available information, pasteurization is likely to inactivate the virus, however the process is not expected to remove the presence of viral particles,” the FDA explained. “Therefore, some of the samples collected have indicated the presence of HPAI [Highly Pathogenic Avian Influenza] using quantitative polymerase chain reaction (qPCR) testing.”
The FDA did not indicate how many samples it has tested, where the samples were collected from, or the level of viral genetic material the samples contained.
The agency is now working on assessing whether it can identify if any virus particles are infectious using egg inoculation tests, which are considered a gold-standard for determining viral viability. It added that it will release results from those tests and others in “the next few days to weeks.”
“[W]e take this current situation and the safety of the milk supply very seriously. We recognize the importance of releasing further, actionable information,” the FDA said.
Meanwhile, the agency reported that the CDC’s food safety group has been closely monitoring emergency department data and flu testing data for any unusual trends in flu-like illness, flu, or conjunctivitis, which could indicate spread of H5N1 to people. “To date, surveillance systems do not show any unusual trends or activity,” the FDA said.
Enlarge/ Chicken eggs are disposed of at a quarantined farm with bird flu in Israel’s northern village of Margaliot on January 3, 2022.
The flare-up of highly pathogenic bird flu continues to widen in US livestock after federal officials confirmed last week that the virus has spread to US cows for the first time. The virus has now been detected in dairy cows in at least five states, a single person in Texas exposed to infected cows, and an egg farm in Texas, all spurring yet more intense monitoring and biosecurity vigilance as the situation continues to evolve.
As of Tuesday, seven dairy herds in Texas, two in Kansas, and one each in Idaho, Michigan, and New Mexico had tested positive for the virus. The affected dairy herd in Michigan had recently received cows from one of the infected herds in Texas. It remains unclear if there is cow-to-cow transmission of the flu virus.
The virus—a highly pathogenic H5N1 avian influenza or HPAI—has been devastating wild birds worldwide for the past several years. Throughout the devastating outbreak, the flu virus has spilled over to various species, including big cats in zoos, river otters, bears, dolphins, seals, squirrels, and foxes. While cows were an unexpected addition to the list, federal officials noted last week that affected dairy farms had found dead wild birds on their farms, suggesting that wild birds introduced the virus to the cows, not an intermediate host.
On Monday, the Centers for Disease Control and Protection reported that a person in Texas who had contact with infected dairy cows had tested positive for the HPAI. The person’s only symptom was eye redness. The CDC said the person was treated with an antiviral for flu and was recovering. It is the second case of HPAI found in a person in the US. The first case was in a person in Colorado who was directly exposed to poultry infected with the virus. In that case, the person’s only symptom was fatigue over a few days. The person recovered. The CDC considers the risk of HPAI to the general public to be low.
Low risk
Meanwhile, the virus continues to spread to less-surprising animals: chickens. On Tuesday, Cal-Maine Foods, Inc., the country’s largest producer of fresh eggs, reported that HPAI was detected in one of its facilities in Texas. The facility is located in Parmer County, which sits at the border of Texas and New Mexico. It’s unclear if the egg facility is close to any of the affected dairy herds. Cal-Maine, following the US Department of Agriculture biosecurity protocols, immediately shut down the facility. Approximately 1.6 million hens and 337,000 pullets—young hens—were culled. Cal-Maine said the hens represented about 3.6 percent of the company’s total flock.
Since the outbreak began in wild birds, the virus has led to the deaths of over 82 million commercial and backyard birds in the US, with 48 states affected and over 1,000 outbreaks reported. The infections have spurred increases in egg and poultry prices.
It’s unclear if the virus will have the same effect on milk or beef, but so far, it appears that it will not. In the infected herds, the virus appears to only be affecting a small percentage of animals, particularly older animals, and they generally recover. As the USDA puts it there’s “little to no associated mortality reported.” Milk from sick cows is always diverted from the milk supply, but even if milk contaminated with HPAI were to make it into the supply, the virus would be destroyed in the pasteurization process.
Still, the continued, widespread outbreak and spillovers of HPAI in various species highlight the ever-present risk that influenza viruses could mix together, combining genetic fragments of different strains (genetic reassortment) to create a new strain that could spark outbreaks or even a pandemic in humans. In the current outbreak among dairy cattle, federal researchers were quick to check the genetic sequence of the HPAI, finding that, so far, the strain lacks mutations in key genetic regions that would signal the virus has become more infectious to humans. For now, the USDA and the CDC report that the risk to the public is low.
