Each year, the flu vaccine undergoes a meticulous process to ensure its efficacy in combating the influenza virus. With numerous strains of influenza circulating, it is important to accurately predict which strains will dominate each flu season. The effectiveness of the vaccine hinges on the accuracy, as it aims to either prevent individuals from contracting the flu or decrease the severity of illness if infection does occur.
To achieve this level of precision, scientists use multiple approaches. One such method is epidemiologic data analysis, which involves tracking the spread and prevalence of different flu strains across populations. By monitoring patterns of infection and transmission, researchers can identify trends and anticipate which strains are likely to predominate in the upcoming season.
Genetic data also plays a crucial role in the forecasting process. Laboratories worldwide conduct genetic sequencing on viral samples obtained from infected individuals, enabling scientists to analyze the genetic makeup of different flu strains. By comparing the genetic sequences of these strains, researchers can discern patterns of mutation and evolution, providing insights into how the virus may evolve over time and which strains are most likely to circulate in the future.
Furthermore, scientists examine the antigenic properties of flu viruses to assess their similarity to previous strains and predict their potential impact on vaccine effectiveness. Antigens, found on the surface of viruses, stimulate the production of antibodies in the body's immune system. By studying these antigens, researchers can see how well the current vaccine will combat circulating flu strains.
Human serology studies also contribute valuable data to the forecasting process. These studies involve analyzing blood samples from individuals exposed to different flu strains to measure their immune response. By assessing levels of antibodies specific to various flu viruses, researchers can gauge population immunity and susceptibility to different strains, aiding in the prediction of which viruses are likely to cause outbreaks in the future.
Global surveillance efforts coordinated by organizations like the World Health Organization (WHO) further enhance the accuracy of flu forecasting. Through year-round monitoring of flu activity worldwide, including peak seasons in both the northern and southern hemispheres, epidemiologists can identify emerging strains and assess their potential threat to global public health. This global perspective enables researchers to anticipate how flu viruses may spread and evolve, informing vaccination strategies and pandemic preparedness efforts.
In addition to these methods, evolutionary analysis plays a critical role in flu forecasting. By examining the evolutionary dynamics of flu viruses, researchers can predict how different strains may compete with one another and evolve to evade immune detection. This understanding of viral evolution helps inform the development of vaccines that target the most prevalent and virulent flu strains, maximizing their effectiveness in protecting against seasonal influenza.
Olivia Khangi is a participant in the Niagara County NYS Public Health Corps Fellowship program at Mount St. Mary's and Lockport Memorial hospitals. The Right Way to Care by Catholic Health is produced by the hospitals' public relations and marketing department.
This article is an installment of Future Explored, a weekly guide to world-changing technology. You can get stories like this one straight to your inbox every Thursday morning bysubscribing here.
On April 5, the CDC issued a health alert informing the public and the medical community that a person in the US had contracted avian flu something that had only happened once before. Less than a week earlier, the virus had been spotted in herds of dairy cows in the US.
So, how worrying is it that bird flu jumped to a person and what can we do to stop the virus from becoming a bigger problem in the future?
There are four types of influenza viruses: A, B, C, and D. Type A and B viruses regularly infect people, and certain type A viruses can infect birds, pigs, dogs, and several other species, too.
Usually, a subtype of influenza that infects one species doesnt readily infect another, but as the virus spreads, it can mutate or recombine with other flu viruses in ways that allow it to make the jump to a new species. In March 2024, the USDA reported that a strain of avian flu H5N1 2.3.4.4b had infected herds of dairy cows in five states, and chicken producers across the country are also culling millions of birds in efforts to control outbreaks in poultry.
A person working on a dairy farm with infected cows in Texas soon tested positive for the avian flu, leading experts to suspect he contracted the virus from a cow.
This is the first time avian flu has been detected in US livestock and the first time a human has seemingly contracted the virus from a mammal (and not from exposure to an infected bird), but that doesnt necessarily mean were on the brink of a new pandemic.
The chance of you getting sick from the milk of an infected cow is extremely low.
Even though these are the first reported cases of avian flu in cows, H5N1 has been detected in more than 30 mammal species previously, so the virus making the leap into one more isnt entirely surprising.
The fact that these are dairy cows and therefore in the human food chain does make this more noteworthy than, say, when the virus was spotted in tigers for the first time, but the chance of you getting sick from the milk of an infected cow is extremely low, thanks to pasteurization.
Farmers are also being directed to destroy milk from any cows they know are infected.
H5N1 virus particles (gold) grown in canine kidney cells (green)
It isnt entirely clear how the virus is spreading in cattle it could be spreading through the air, through contaminated milking equipment, or some other vector. While mammals usually contract H5N1 from a bird and then either recover or die without spreading the virus to other mammals, mammal-to-mammal transmission isnt entirely unheard of.
In 2022 and 2023, the virus appeared to spread between farmed minks, and some people whove contracted the virus in the past had no known contact with infected birds before getting sick, suggesting that they might have gotten it from another person or mammal, too.
That makes the spread of the virus between cows rare, but not unprecedented, and thankfully, the virus isnt making the animals too sick they have mild fevers, decreased appetites, and decreased milk production, but recover fairly quickly.
The farmer who caught the virus from a cow, meanwhile, only had one symptom conjunctivitis (pink eye) and is now recovering after treatment with an antiviral medication.
The US has been studying H5N1 for years and has stockpiled avian flu vaccines.
While the CDC notes that the current risk to the public remains low, the more opportunities the avian flu virus has to spread, the more chances it gets to mutate into something that is dangerous.
Thankfully, the US has been studying H5N1 for years and has stockpiled avian flu vaccines and treatments just in case the virus becomes more contagious or starts to cause more severe infections. Other ways to protect humans and livestock from the virus are in the works, too.
The fact that weve already developed avian flu vaccines means that, if a threatening strain of bird flu emerges, we should be in a better place than we were at the start of the COVID-19 pandemic, when we didnt have any coronavirus vaccines.
However, the vaccines we have for bird flu might not be as effective as they were when they were first developed.
By the time a targeted shot was designed and manufactured, the virus could be widespread.
Flu viruses mutate readily, and because a vaccine that works great against one strain might not be effective against another, developers of human flu vaccines tweak their shots every year to target the handful of strains they think will dominate the upcoming flu season.
Unfortunately, because it takes a long time to manufacture large quantities of flu vaccine using the traditional method growing the virus in chicken eggs and then inactivating it they need to pick a target 6-9 months in advance, and that long lead time can make it hard to choose the best one.
We could face this same problem with avian flu vaccines.
The strain that infected the Texas farmer was closely related to the ones used for existing avian flu shots, according to the CDC, but not an exact match. A strain that was able to spread from person to person could be significantly different, and by the time a targeted shot was designed and manufactured, the virus could be widespread.
Even if a potential epidemic strain wasnt radically different, though, a bird flu outbreak could actually kill a lot of the chickens that we need to lay the eggs to make a vaccine and the more the virus spreads, the more chances it has to mutate and dodge our immune defenses.
A lab worker injecting a human flu virus into eggs during the manufacturing process
mRNA vaccines the kind approved for COVID-19 can be designed and manufactured more quickly than traditional flu shots, and they dont require any birds or eggs, which could make them a better option in the event of a future avian flu outbreak.
Several vaccine makers are already developing the shots, too, including Moderna in March 2023, it announced that it was working on an mRNA-based avian flu vaccine, which it said it planned to test in humans before mid-year (though there hasnt been an update on the shot since).
Researchers at the University of Pennsylvania, meanwhile, published a paper in 2022 detailing a promising mRNA-based vaccine that targets 20 strains of flu, including H5N1, and in 2023, they shared a preprint of a study that found a version targeting H5N1 2.3.4.4b, specifically, was effective in animals.
More research is needed to get any mRNA shot for bird flu across the finish line, but developing them now before a threatening strain is already spreading means we have a better chance of having one ready if we need it.
Because the avian flu starts in birds, stopping them from getting infected in the first place could be an even better way to prevent a pandemic, not to mention save the lives of potentially millions of birds and protect the global supply of eggs and poultry.
Avian flu vaccines for birds could be one way to do that.
In 1994, Mexico became the first nation to vaccinate chickens against a strain of bird flu, and more than a dozen others have since followed suit, with China relying heavily on vaccination to protect its flocks.
US farmers have avoided avian flu vaccines for livestock due to issues with exporting poultry and eggs from vaccinated birds. Instead, as in many countries, they rely on culling to stop outbreaks if one bird tests positive, the entire flock is killed.
That could change, though.
Maybe its time to discuss vaccination.
In April 2023, the USDA began trialing several vaccines to protect birds against H5N1 2.3.4.4b, and the following month, the World Organisation for Animal Health an intergovernmental group focused on animal disease control suggested that vaccines should be considered.
Since almost every country that does international trade has now been infected, maybe its time to discuss vaccination, in addition to systematic culling which remains the main tool (to control the disease), Monique Eloit, WOAHs director general, told Reuters.
Vaccine development is slow going, though, with US Agriculture Secretary Tom Vilsack telling Congress in February 2024 that the USDA is probably 18 months or so away from identifying a vaccine that would be effective against the strain of avian flu thats currently spreading.
Even if the USDA does develop an effective vaccine for this strain, it then needs to work out the logistics of manufacturing and distributing the shots and then go through the process again for future strains.
Gene-editing offers a promising route towards permanent disease resistance.
A more radical idea for protecting poultry from avian flu is taking shape in the UK, where scientists are trying to use CRISPR to genetically engineer chickens that cannot catch the flu at all.
In 2023, the team announced that editing one gene stopped chickens from producing a protein that the avian flu virus uses to replicate itself inside cells. When intentionally exposed to the virus, just one out of 10 gene-edited birds was infected, and that one didnt spread the virus to any others.
The UK researchers suspect theyd need to make two more edits to the chickens to confer total immunity, and more research is needed to see how that might affect the health of the birds. If it proves safe and effective, though, the CRISPR approach could be a lasting solution to the bird flu problem in chickens.
Gene-editing offers a promising route towards permanent disease resistance, which could be passed down through generations, protecting poultry and reducing the risks to humans and wild birds, said Mike McGrew, the studys principal investigator, in October 2023.
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With growing concern among biologists about the spread of the so-called bird flu to cattle in the U.S., the worry now is that more humans could catch the virus.
AUSTIN, Texas Microbiologists say that the recent discovery that avian flu has spread from birds to cattle came as a surprise. Texas was one of the first states to report that H5N1 had spread to dairy cattle in the state.
Last week, Texas health officials confirmed that avian flu spread to a farm worker in Texas who tended to cattle. Although theres been no indication that avian flu can spread from person to person, just in case the virus mutates, researchers are preparing.
The Texas Biomedical Research Institute (Texas Biomed) in San Antonio recently received U.S. government approval to begin looking into developing potential vaccines and antivirals that could combat avian influenza.
I think there is no cause for immediate alarm here. Weve been tracking this virus," Dr. Larry Schlesinger, president and CEO of Texas Biomed, said. But the future could indicate that the virus could continue to change in a way that might cause it to be more of a problem in humans. And we have to be highly vigilant on this particular strain of virus.
Schlesinger said theres no reason for undue concern that the flu will become commonplace among humans. But he said its important for biomedical researchers to investigate developing a vaccine, just in case.
On Thursday, South Dakota became the eighth state to confirm that a type of the virus labeled H5N1 was found in dairy cattle. North Carolina reported Wednesday that the same virus made its way to some dairy cattle there.
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Introduction
Avian influenzaoften referred to as avian flu or bird fluis a virus that has circulated among the worlds migratory birds for at least a century. However, in recent decades, new, highly pathogenic strains of the virus have wreaked havoc on certain bird populations, particularly poultry livestock, and become a growing threat to humans and other mammals.
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Since 2020, cases have been rising in other birds and in mammals that were not previously susceptible. The global surge in outbreaks has forced agriculture companies to cull millions of poultry, the most consumed meat in the world, and threatened some endangered species. Meanwhile, drawing on the harsh lessons of the COVID-19 pandemic, scientists and policymakers are raising concerns about the prospect of avian flu morphing into the next zoonotic pandemic.
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First discovered in 1878, avian influenza is a viral disease that primarily infects birds, although some strains can spread to and kill mammals, including humans. The H5N1 strain, one of the most common today, was first identified in domestic waterfowl in 1996.
A curation of original analyses, data visualizations, and commentaries, examining the debates and efforts to improve health worldwide.Weekly.
Birds. The flu mainly spreads asymptomatically among wild aquatic birds, but domestic poultry are also susceptible and can become extremely ill and die. Twenty-five known subtypes of avian flu have been identified in birds. There are two main categories: low pathogenicity, which often causes little-to-no signs of disease, and high pathogenicity, strains that cause severe disease and poultry mortality. Highly pathogenic strains of avian influenza have a 90 to 100 percent mortality rate among poultry. Most infected livestock die within forty-eight hours.
Humans. Human cases of bird flu are extremely rare, but often deadly. Most people who have been infected have usually been directly exposed to infected poultry or contaminated environments by them. Human-to-human transmission is believed to have only occurred in a few isolated instances, but sustained transmission between humans has not yet been identified. The two strains of avian flu that have killed the most people are H5N1 and H7N9. The first human cases of H5N1 were detected in China in 1997, but the bulk of cases came between 2003 and 2015, with Egypt as a hot spot. To date, there have been 882 human cases, with 461 deaths across nearly two dozen countries, according to World Health Organization (WHO) data.
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H7N9 was also first reported in China in 2013, and it has killed more than six hundred people to date. Some non-fatal cases are asymptomatic, but common effects can include flu-like symptoms, conjunctivitis (pink eye), pneumonia, multi-organ failure, seizures, and neurological damage. Newer strains that later evolved, such as H5N6 and H5N8, are also infecting humans.
Other mammals. Since 2020, avian flu has been found in close to fifty mammal species across more than two dozen countries, considerably more widespread than past waves. The disease can often be deadly for mammals. There have been notable outbreaks in mink in Spain, seals in Peru, and even domestic cats and dogs in several countries. Most recently, at the beginning of 2024, H5N1 was found in seals in Antarctica for the first time.And as of March, avian flu wasreportedly worsening in marine mammals at rates that have prompted scientists to become concerned about mammal-to-mammal transmission, which would represent a much more dangerous threat to the affected ecosystems. In April, the virus was detected in U.S. cattle for the first time, affecting herds in several states. At least one farm worker, in Texas, was also infected.
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H5N1began circulatingin parts of Africa, Asia, and Europe in late 2021, but its reach has exploded since then: the virus has been recorded in more than eighty countries since 2022. There have been recent cases in all continents except for Australia.
In the current wave, relentless outbreaks in poultry have wracked U.S. agriculture nationwide as well. Avian flu has been recorded in forty-eight states and affected more than eighty-two million poultry, as of March 2024. European countries witnessed a similar pattern of surging infections, affecting some fifty million poultry across thirty-seven countries, though France suffered the brunt of these. Other countries, such as Japan and South Africa, experienced their worst avian flu outbreaks among farmed birds.
Avian flu outbreaks can cost farmers and consumers billions of dollars in lost profits and higher prices, and they disrupt important international trade. The ongoing avian flu outbreak in the United States, the worlds largest poultry meat producer and second-largest egg producer, caused economic losses around $2.53 billion by the end of 2023, and experts expect this cost will only rise amid new surges of the disease in 2024. Avian flu has led to the deaths or culling of more than eighty million poultry livestock. Per U.S. regulations, producers must cull all the birds in an infected flock, even if some of them do not have the disease. Amid the outbreak, the cost of a dozen eggs more than doubled to nearly five dollars in January 2023 before producers were able to restore their flocks. In recently infected cattle, U.S. farmers have reported reduced milk production, although it has had a limited effect on supplies thus far.
The reduction of poultry has exacerbated food security in some parts of the world, particularly in lower-income countries where poultry products are a major source of protein. South Africas poultry industry underwent major supply shortages in 2023 as its worst avian flu outbreak added to its chronic power outages, which further hampered poultry production. Studies in Egypt have recorded stunted growth in youth coinciding with past avian flu outbreaks.
Avian flu and the perceptions around it can also harm the global trade of poultry products. Amid a 2004 outbreak in the United States, for example, U.S. poultry exports dipped more than 20 percent after several countries imposed embargoes on U.S. poultry products. These trade constrictions also reduce incomes for producers whose flocks never even contracted the virus, as well as for others involved in the poultry value chain. These economic concerns have rendered several countries wary of vaccinating poultry for avian flu, as they do not want to risk potential embargoes from their trading partners.
The global spread is due in part to bird migration patterns, allowing infected birds to carry the disease thousands of miles to sites along their flyways. At the same time, the virus is increasingly mutating as it encounters new host animals and new species.
Outbreaks in the past often subsided in the summer when bird migrations ceased, yet this was not the case in the recent H5N1 strain, which was some of the cause for scientists concern. The constant stream of outbreaks across the world in 2023 triggered concerns that avian flu could become a year-round threat. The reasoning for the viruss persistence is still not fully clear, although some research has indicated that climate change and human activities are contributing factors. Climate changerelated fluctuation in conditions such as temperature are altering the timing of some bird behaviors, including migration and breeding. Meanwhile, habitat destruction and urbanization are also affecting breeding site availability. The confluence of these factors drives birds from different parts of the world to come into contact with each other for the first time and interact with more habitats, both natural and urban. Such encounters expand the opportunities for the virus to spread and mutate.
The corporate consolidation of U.S. factory farms, where poultry livestock are typically held in close quarters, also contributes to the rapid spread of the virus and mass poultry deaths. The environmental nonprofit Food and Water Watch said in a 2020 study [PDF] that 96 percent of U.S. chickens are raised under a production contract by major corporations, such as Tyson Foods or Perdue Farms.
Human cases of avian flu are rare, and experts say the threat to public health is generally low. However, human cases have a high fatality rate, at more than 50 percent. (At its peak, for comparison, the global COVID-19 death rate was reported to be around 8 percent, though it is widely thought to be far higher.) Still, health experts are worried about the risks to farm workers who could be regularly exposed to infected animals.
For a virus to have pandemic potential, it needs to be able to pass easily from person-to-person. H5N1 does not have the ability to do so, but scientists fear it could develop this feature.
The bigger picture is that this virus is not cooling off, CFR Senior Fellow Jennifer Nuzzo toldPolitico. Weve been worrying about this virus for twenty years, more than twenty years. And in the last year, it has really been remarkable in how far across the globe it has been spreading, and how many species its been affecting.
The WHO warns that the recent surge in avian flu outbreaks among mammals could increase the viruss ability to circulate more easily among humans. As viruses quickly spread and evolve, they can more easily mutate and create new strains that are more effective at infecting people. In April 2024, the United States reported its second-ever case of H5N1, a human who became infectedvia sick dairy cattle in Texas, raising concerns of growing mammal-to-mammal transmission. Amid these latest outbreaks, the Centers for Disease Control and Prevention (CDC) is also recommending against the consumption of raw milk, which is sold legally in most states.
Countries such as Egypt and Indonesia experienced the brunt of human cases in the 2015 wave, and in the current wave, Cambodia and the United Kingdom have the highest numbers, which are much lower still than those seen in the prior outbreaks. Nonetheless, the ongoing bouts of avian flu in countries that have never experienced cases in mammals has evoked international attention.
The Food and Agriculture Organization (FAO), WHO, and World Organization for Animal Health (WOAH) are urging countries to work together across sectors to prevent both human and animal infections. Their recommendations include enhanced surveillance and information sharing; increased biosecurity measures, such as vaccinating livestock; restricted contact with other farms and equipment; and proper hygiene and disinfection of farm equipment and facilities.
There are avian flu vaccines for humans and birds, but there are a number of challenges and uncertainties with both. For instance, there is global hesitancy over the bird vaccine for trade reasons, and the existing human vaccines are derived from previous strains, so it could take a while to develop new ones and implement them on a mass scale. Some countries fear that importing vaccinated birds will make conducting surveillance more difficult, as it will be harder to determine if birds have been infected or vaccinated. To some degree, there are concerns that importing eggs or meat from birds that have been vaccinated could inadvertently spread the disease within the importing countrys borders, though there is no evidence to suggest this is possible.
Avian flu vaccines are mostly administered to birds in countries where the flu is endemic, and that have minimal poultry trade, such as Egypt, Indonesia, Mexico, and most recently, France. Commercial poultry in the United States receive other vaccinations, such as against fowlpox, but not yet for avian flu. The U.S. Department of Agriculture (USDA) is testing several bird vaccines but has not approved any, mostly over concerns that requiring a vaccine will harm trade. Despite this roadblock, experts have increasingly called for the U.S. government to launch a vaccination campaign for poultry, which they say would reduce the risk of spillover that could trigger a pandemic. Some poultry vaccines have proven to be as high as 94 percent effective.
There is also a lot of uncertainty around the prospects of an avian flu vaccine for humans. Several major companies that manufacture them have said they could expedite the production of millions of doses in the event of a pandemic. The United States has an emergency stockpile of H5N1 vaccines, but experts have said that they would be insufficient if this particular strain were to start infecting people at a larger scale. Further, the shots have only been administered in trials and were derived from strains that circulated in 2004 and 2005. Some companies are working on developing vaccines that better match the highly pathogenic subvariant that is causing havoc today, but experts say it is unclear whether a human vaccine could be manufactured at a global scale while staying ahead of the curve on the viruss rapid mutation.
We shouldnt be overconfident in our ability to make vaccines that are safe and effective for avian flu because weve encountered challenges in the past with that antigen, says CFR Fellow Luciana Borio. Clinical trials involving H5N1 in the past have yielded lackluster results.
And as with many diseases, there is a global equity issue: these vaccines, which are not even past the testing phase, are already slated to go to richer countries first, leaving lower-income countries at risk. We cant do a repeat of what happened with COVID, where countries that were vaccine-producing waited until there was no more interest in vaccines in their populations before they really worked to consider the needs of developing countries and non-vaccine-producing countries, Borio says.
The recent detection of H5N1 bird flu in U.S. cattle, coupled with reports of a dairy worker contracting the virus, demands a departure from the usual reassurances offered by federal health officials. While they emphasize theres no cause for alarm and assert diligent monitoring, its imperative we break from this familiar script.
H5N1, a strain of the flu virus known to infect bird species globally and several mammalian species in the U.S. since 2022, has now appeared to have breached a new barrier of inter-mammalian transmission, as exemplified by the expanding outbreak in dairy cows in several jurisdictions linked to an initial outbreak in Texas. Over time, continued transmission among cattle is likely to yield mutations that will further increase the efficiency of mammal-to-mammal transmission.
As the Centers for Disease Control continues to investigate, this evolutionary leap, if confirmed, underscores the adaptability of the H5N1 virus and raises concerns about the next step required for a pandemic: its potential to further evolve for efficient human transmission. Because humans have no natural immunity to H5N1, the virus can be particularly lethal to them. Despite assertions of an overall low risk of H5N1 infection to the general population, the reality is that the understanding of this risk is limited, and its evolving alongside the virus. The situation could change very quickly, so it is important to be prepared.
Comparisons to seasonal flu management underestimate the unique challenges posed by H5N1. Unlike its seasonal counterparts, vaccines produced and stockpiled to tackle bird flu were not designed to match this particular strain and are available in such limited quantities that they could not make a dent in averting or mitigating a pandemic, even if deployed in the early stages to dairy workers. The FDA-approved H5N1 vaccines licensed in 2013, 2017, and 2020 do not elicit a protective immune response after just one dose. Even after two doses, it is unknown whether the elicited immune response is sufficient to protect against infection or severe disease, as these vaccines were licensed based on their ability to generate an immune response thought to be helpful in preventing the flu.
Early studies done by mRNA vaccine companies on seasonal flu are promising, which could be good news here since mRNA vaccines can be made more quickly than vaccines using eggs or cells. Congressional funding is needed to catalyze rapid vaccine development and production.
While FDA-approved antiviral drugs like Tamiflu and Xofluza could be an important line of defense against H5N1, logistical barriers impede their timely administration, as they work best when given as early as possible within 48 hours of the onset of symptoms. Most Americans would find it challenging to get a prescription filled for these medicines within the optimal time frame. Streamlining access to stockpiled antiviral drugs through improved test-to-treat measures like behind-the-counter distribution or dedicated telemedicine consultations could vastly improve their effectiveness as a frontline defense. Making plans to do that need to start now.
For vulnerable people older adults and anyone who is immunocompromised clinicians have become accustomed to relying on monoclonal antibodies. Sadly, their performance for flu has been disappointing in many clinical trials and cant be counted on.
The need for robust diagnostic capabilities cannot be overstated. H5N1 will not be detected by the typical rapid flu antigen tests that are administered in emergency rooms and many doctors offices. New tests will have to be made from scratch. The dismantling of diagnostic infrastructure post-Covid-19 and supply chain disruptions, however, pose significant challenges to the availability of such tests. Rapid investment in diagnostic testing, coupled with efforts to secure essential materials, is imperative to ensure timely detection and antiviral treatment.
President Bidens emphasis on infrastructure presents a unique opportunity to fortify Americas defenses against infectious diseases. A national initiative to enhance indoor air quality in schools and communal spaces could mitigate transmission risks should this virus learn how to efficiently be transmitted between humans, and would pay dividends every respiratory virus season and for years to come.
In the face of uncertainty, complacency is not an option. The U.S. must act decisively, acknowledging the potential gravity of the H5N1 situation while leveraging every available resource to safeguard public health. The stakes are too high to repeat past mistakes.
Luciana Borio is an infectious disease physician, a senior fellow for global health at the Council on Foreign Relations, a venture partner at ARCH Venture Partners, and former director for medical and biodefense preparedness policy at the National Security Council. Phil Krause is a virologist, infectious disease physician, and former deputy director of the Office of Vaccines Research and Review at the FDA. The authors have no links to any companies producing or evaluating any of the vaccines or therapies mentioned in this article, and declare no conflicts of interest.
US news
Ca-Maine Foods, largest fresh egg producer in US, temporarily halts production at one Texas facility after discovering virus
Fri 12 Apr 2024 07.00 EDT
Avian influenza has been detected among chickens in Texas and Michigan, following news of the virus infecting livestock and then a person for the first time in the US and potentially leading to supply chain issues.
The developments have led to a heightened focus on the potential risks of the virus, especially in the wake of the devastating coronavirus pandemic. But experts are saying that there is little chance of transmission between humans at this point.
Cal-Maine Foods, the largest producer of fresh eggs in the US, has temporarily halted production at one Texas facility and is killing 1.6 million hens and 337,000 chicks 3.6% of its entire flock after discovering the highly pathogenic virus among its domesticated birds.
These are hard times for dairies and the poultry folks, said Lewis R Bud Dinges, Texas state veterinarian and executive director of the Texas animal health commission.
Outbreaks like these may have repercussions on the price of poultry and eggs, particularly if the virus keeps spreading in domesticated flocks much like the 2022-23 outbreak that raised the price of eggs by 70%. Continued spread among chickens could also threaten the production of the flu vaccine, which relies on 140m eggs a year to incubate inoculations.
The CDC released a health advisory notice last Friday, recommending that doctors keep a lookout for possible avian flu among patients, especially those who frequently come into close contact with birds and animals.
Anyone in contact with birds and livestock, including agricultural workers, hunters, and backyard farmers, should wear protective gear and follow strict hygiene standards. They just need to pay extra attention to biosecurity and cleaning and disinfecting, Dinges said. Make sure they wash their hands and wear protective clothing and leave their clothing at the facility where they work clothing and footwear if at all possible.
An inmate who was culling infected flocks in Colorado became the first person in the US with a known bird flu infection in 2022.
On 20 March, Minnesota reported that baby goats were sickened by bird flu, marking the first time the virus had been discovered in livestock. Days later, the virus was also discovered among cows. Cows in North Carolina tested positive for bird flu on Wednesday, bringing the affected count up to 21 herds in seven states.
Genomic sequencing revealed that the spillover to cows did not seem to make the virus more transmissible to humans this time, so the risk of sustained human-to-human transmission is still low, said Seema Lakdawala, associate professor of microbiology and immunology at Emory University School of Medicine.
Transmission of influenza viruses in humans requires lots of different variables to align just right, and the current H5N1 viruses do not have all the correct parameters for spreading between humans, she wrote in an email.
However, the more the virus spills from birds into other hosts like cattle, foxes, seals, etc the more likely the virus is to change and gain properties that could lead to successful human-to-human transmission.
Avian influenza is an emerging disease among livestock, Dinges said, and theres a lot that we dont know about the pathogenesis in the cow itself. Were still kind of learning as we go here.
Its not clear how the herds encountered the virus, but the genomic sequences are very similar pointing to a single introduction, probably from a dead bird, that spread within the herds rather than several introductions over time.
The outbreak among dairy cows could lead to local shortages, but for now its unlikely to create national or regional shortages or price increases, said Tinglong Dai, professor of business at the Johns Hopkins University Carey Business School. Thats because the US is in its high season for milk production.
In the spring and summer, usually, you have higher yields than during the winter, he said. Suppose this happened in the fall or in the winter: the supply chain impact would have been much bigger.
If the outbreak among cows continues in the fall, it could affect supply and prices. In the meantime, affected cows are being isolated until their illnesses pass.
Chickens, on the other hand, usually die from the virus, so producers cull them as soon as the virus is detected.
The most effective way to stop the spread is to kill the chickens, Dai said. That means prices for poultry and eggs could be more affected by this outbreak than for milk and cheese.
The manufacturing process for flu shots also relies heavily on eggs, and egg shortages in the past have led to vaccine shortages. So far, no vaccine makers have reported shortages.
Its just if the situation keeps going if infection spreads, again, we need to monitor very, very closely, Dai said. This also depends on how this is going to evolve in the coming days.
Scientists are sounding the alarm in order to keep farmers and other agricultural workers safe, and to continue monitoring the spread of the virus.
For example, its not clear how common it is for avian influenza to spill over from birds to animals, Lakdawala said. Currently, in the US, most of this surveillance is from examination of animals that are found sick or died.
If the virus has been quietly spilling over into other animal hosts that dont get very sick or die as with white-tailed deer and Covid scientists dont know about it. Thats why they need more funding for monitoring concerning viruses like the flu, Lakdawala said.
This is a gap we need to try to fill, but is hard to do without more resources and investment into large-scale surveillance programs.
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Dairy worker's bird flu case sparks concern as experts wonder about spillover to humans
CHATHAM COUNTY, Ga. (WTGS)
The recent bird flu infection of a dairy worker in Texas has placed officials and scientists on high alert. Although experts say the virus isnt something to panic about, it certainly is something to keep an eye on.
Doctors told WTGS that the virus has a mortality rate of around 50% in humans. While it hasnt infected a lot of humans, this week the CDC asked states to be ready with testing.
"An ounce of prevention is worth a pound of cure," said Timothy Connelly, an internal medicine physician at Memorial Health.
The initial symptoms of bird flu are very similar to COVID-19 or the regular flu, such as muscle aches and upper respiratory symptoms that could have you reaching for ibuprofen. Connelly said the medication that is highly effective in this instance is Tamiflu. It works best if given within 48 hours of getting infected.
The virus is contagious and is spread through the air.
"It is not easily spread between humans. Usually, people get it from birds," said Connelly. "But as we have seen, recently people have been able to get it from cows. It hasnt been a lot of animals that have been infected. There have been a significant number of chickens and poultry birds that have been infected. The FDA has identified them and taken them out of the food supply. If you were to consume an animal that was infected, if you cooked it properly that would kill the virus. It is not something that we are super concerned about right now."
While there are four vaccines licensed for avian influenza, none are approved for the more dangerous bird flu strain: H5N1. A vaccine specifically for that strain is in trials.
Connelly said there is some degree of protection with the traditional flu shot.
Poultry farms across Georgia serve as one of the state's leading cash crops. A lot of migrant birds pass through southeastern Georgia, and they bring with them disease.
"Agriculture workers are the most likely individuals to get infected with this first," Connelly said. "Particularly people who work with birds. The migratory pattern of birds is what spreads this. We are towards the end of the migratory season. We are hoping it doesnt become an issue this year. But every year we have been seeing more species getting bird flu, more mammals getting bird flu, and more pathology with bird flu."
In the coming months, Connelly said the big question is how we'd be able to treat it if a lot of people were to get it at one time. He added that preparation is the best way to avoid the question.
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Infectious disease expert Dr. Peter Chin-Hong joins LiveNOW's Austin Westfall to analyze the level of concern after a person contracted bird flu in Texas.
The United States is currently grappling with a bird flu outbreak, which has affected two dozen dairy cow herds across eight states. This comes just weeks after the nation's largest egg producer detected the virus in its chickens.
Despite the disease's spread, health officials urge the public to stay calm, emphasizing that the risk to the public is minimal and assuring that the nation's food supply remains secure.
"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," the U.S. Food and Drug Administration said in a statement.
RELATED: Bird flu: Can humans get infected?
Here's a simple rundown of what's happening with the outbreak and how it affects the safety of your food.
Yes, as health officials have mentioned before, there's no worry about the U.S. food supply.
While it's possible for people to catch bird flu if they're in close contact with infected birds, it doesn't happen often.
Since 2020, a bird flu virus has been circulating among a broader range of animal species, including dogs, cats, skunks, bears, seals, and porpoises, across numerous countries.
However, experts advise against panicking, emphasizing that the risk to the general public is minimal and there is no evidence of sustained human-to-human transmission.
U.S. producers cannot sell milk from sick cows and must dispose of it. Moreover, milk sold between states must undergo pasteurization, a heat treatment process that eliminates bacteria and viruses, including influenza.
"We firmly believe that pasteurization provides a safe milk supply," Tracey Forfa, director of the FDAs Center for Veterinary Medicine told a webinar audience this week.
The FDA and the CDC express uncertainty regarding unpasteurized, or raw, milk sold in numerous states, citing limited information on potential H5N1 virus transmission in these products.
While no herds associated with raw milk suppliers have reported bird flu-infected cows thus far, both agencies advise the industry against producing or selling raw milk or raw milk cheese products from cows displaying symptoms or those exposed to infected cows.
U.S. health officials have long warned against the risk of foodborne illness tied to raw milk, which the CDC said caused more than 200 outbreaks that sickened more than 2,600 people between 1998 and 2018.
After reports surfaced earlier this month of a dairy worker in Texas contracting a highly pathogenic strain of bird flu, it's understandable that concerns about a potential broader health emergency may arise. But this is only the second case of a person in the U.S. being diagnosed with the Type A H5N1 virus.
The first instance occurred in 2022 when a prison inmate participating in a work program contracted the virus while culling infected birds at a poultry farm in Montrose County, Colorado. Despite experiencing fatigue as the sole symptom, the individual made a full recovery.
According to agriculture officials, only dairy cows, not beef cattle, have been infected or displayed signs of illness thus far.
The largest egg producer in the U.S. suspended operations on April 2 upon discovering bird flu in its chickens. Cal-Maine Foods euthanized approximately 1.6 million laying hens and an additional 337,000 pullets (young hens) following the detection.
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FOX 7 Austin's John Krinjak joins LiveNOW's Austin Westfall with a live report on a human case of bird flu being confirmed in Texas.
The company reassured consumers that there was no risk to eggs in the market and that no eggs had been recalled.
Eggs that are handled properly and cooked thoroughly are safe to eat, said Barbara Kowalcyk, director of the Center for Food Safety and Nutrition Security at George Washington University.
"A lot of people like runny eggs. Personally, if I eat an egg, its very well cooked," she said.
The Associated Press contributed to this report. This story was reported from Los Angeles.
PIERRE, S.D. Minnesota dairy farmers are on the lookout after officials announced Friday that a herd of cattle in South Dakota tested positive for bird flu.
The highly pathogenic avian influenza has been impacting bird populations in Europe and Asia since August of 2020. Last week, the U.S. Department of Agriculture confirmed the bird flu had spread to cattle in dairy farms for the first time. The virus was detected in farms in Kansas and Texas.
South Dakota is now the eighth state with the avian flu confirmed in their cattle.
Dairy farmers in Minnesota are being advised to limit dairy cow exposure to wild birds, which is easier said than done in the midst of the spring migration.
"There are sound barrier things that you can do that deter birds from being around. And that's something we are heavily looking into," said Colette Thorson of Diers Corporation. "Everything is closed here. Even our own feed sources, generally, is from our field."
Cow collars also tell Thorson if one of her cows has stopped eating.
"It sends me alerts on my phone. It's very much like an Apple watch," said Thorson. "We do a lot here to control any virus of any sort."
Turkey flocks in Minnesota have been wiped out by the bird flu in the past, but Dr. Joe Armstrong with the University of Minnesota says so far, cows aren't affected the same way. Those that test positive, though, are being pulled from milk production.
"We are taking them out of the milk supply and food supply, the impacted animals, but that's the extent of it. There is no reason to be thinking about depopulating or culling or anything at this point because they are not dying. And so we are fortunately not having to worry about that," he said.
MORE NEWS: Western Minnesota goat tests positive for bird flu; first case of its kind in US history
The USDA says pasteurization kills bird flu, and milk and dairy products are safe to consume.
Symptoms of avian flu in cattle include a drop in milk production, loss of appetite, and changes in manure consistency. Producers should limit visitors and separate the sick and new animals, the South Dakota Department of Agriculture and Natural Resources said.
Officials say they're not concerned about the safety of commercial milk supply as the U.S. typically has more sufficient milk supply in the spring.
Health officials say that while there have been cases of bird flu spreading to humans, the instances are rare.
John Lauritsen is an Emmy award-winning reporter from Montevideo, Minn. He joined WCCO-TV in late-July of 2007. Two days after he started, the Interstate 35W bridge collapsed.
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On April 5, the CDC issued a health alert informing the public and the medical community that a person in the US had contracted avian flu something that had only happened once before. Less than a week earlier, the virus had been spotted in herds of dairy cows in the US.
So, how worrying is it that bird flu jumped to a person and what can we do to stop the virus from becoming a bigger problem in the future?
There are four types of influenza viruses: A, B, C, and D. Type A and B viruses regularly infect people, and certain type A viruses can infect birds, pigs, dogs, and several other species, too.
Usually, a subtype of influenza that infects one species doesnt readily infect another, but as the virus spreads, it can mutate or recombine with other flu viruses in ways that allow it to make the jump to a new species. In March 2024, the USDA reported that a strain of avian flu H5N1 2.3.4.4b had infected herds of dairy cows in five states, and chicken producers across the country are also culling millions of birds in efforts to control outbreaks in poultry.
A person working on a dairy farm with infected cows in Texas soon tested positive for the avian flu, leading experts to suspect he contracted the virus from a cow.
This is the first time avian flu has been detected in US livestock and the first time a human has seemingly contracted the virus from a mammal (and not from exposure to an infected bird), but that doesnt necessarily mean were on the brink of a new pandemic.
The chance of you getting sick from the milk of an infected cow is extremely low.
Even though these are the first reported cases of avian flu in cows, H5N1 has been detected in more than 30 mammal species previously, so the virus making the leap into one more isnt entirely surprising.
The fact that these are dairy cows and therefore in the human food chain does make this more noteworthy than, say, when the virus was spotted in tigers for the first time, but the chance of you getting sick from the milk of an infected cow is extremely low, thanks to pasteurization.
Farmers are also being directed to destroy milk from any cows they know are infected.
H5N1 virus particles (gold) grown in canine kidney cells (green)
It isnt entirely clear how the virus is spreading in cattle it could be spreading through the air, through contaminated milking equipment, or some other vector. While mammals usually contract H5N1 from a bird and then either recover or die without spreading the virus to other mammals, mammal-to-mammal transmission isnt entirely unheard of.
In 2022 and 2023, the virus appeared to spread between farmed minks, and some people whove contracted the virus in the past had no known contact with infected birds before getting sick, suggesting that they might have gotten it from another person or mammal, too.
That makes the spread of the virus between cows rare, but not unprecedented, and thankfully, the virus isnt making the animals too sick they have mild fevers, decreased appetites, and decreased milk production, but recover fairly quickly.
The farmer who caught the virus from a cow, meanwhile, only had one symptom conjunctivitis (pink eye) and is now recovering after treatment with an antiviral medication.
The US has been studying H5N1 for years and has stockpiled avian flu vaccines.
While the CDC notes that the current risk to the public remains low, the more opportunities the avian flu virus has to spread, the more chances it gets to mutate into something that is dangerous.
Thankfully, the US has been studying H5N1 for years and has stockpiled avian flu vaccines and treatments just in case the virus becomes more contagious or starts to cause more severe infections. Other ways to protect humans and livestock from the virus are in the works, too.
The fact that weve already developed avian flu vaccines means that, if a threatening strain of bird flu emerges, we should be in a better place than we were at the start of the COVID-19 pandemic, when we didnt have any coronavirus vaccines.
However, the vaccines we have for bird flu might not be as effective as they were when they were first developed.
By the time a targeted shot was designed and manufactured, the virus could be widespread.
Flu viruses mutate readily, and because a vaccine that works great against one strain might not be effective against another, developers of human flu vaccines tweak their shots every year to target the handful of strains they think will dominate the upcoming flu season.
Unfortunately, because it takes a long time to manufacture large quantities of flu vaccine using the traditional method growing the virus in chicken eggs and then inactivating it they need to pick a target 6-9 months in advance, and that long lead time can make it hard to choose the best one.
We could face this same problem with avian flu vaccines.
The strain that infected the Texas farmer was closely related to the ones used for existing avian flu shots, according to the CDC, but not an exact match. A strain that was able to spread from person to person could be significantly different, and by the time a targeted shot was designed and manufactured, the virus could be widespread.
Even if a potential epidemic strain wasnt radically different, though, a bird flu outbreak could actually kill a lot of the chickens that we need to lay the eggs to make a vaccine and the more the virus spreads, the more chances it has to mutate and dodge our immune defenses.
A lab worker injecting a human flu virus into eggs during the manufacturing process
mRNA vaccines the kind approved for COVID-19 can be designed and manufactured more quickly than traditional flu shots, and they dont require any birds or eggs, which could make them a better option in the event of a future avian flu outbreak.
Several vaccine makers are already developing the shots, too, including Moderna in March 2023, it announced that it was working on an mRNA-based avian flu vaccine, which it said it planned to test in humans before mid-year (though there hasnt been an update on the shot since).
Researchers at the University of Pennsylvania, meanwhile, published a paper in 2022 detailing a promising mRNA-based vaccine that targets 20 strains of flu, including H5N1, and in 2023, they shared a preprint of a study that found a version targeting H5N1 2.3.4.4b, specifically, was effective in animals.
More research is needed to get any mRNA shot for bird flu across the finish line, but developing them now before a threatening strain is already spreading means we have a better chance of having one ready if we need it.
Because the avian flu starts in birds, stopping them from getting infected in the first place could be an even better way to prevent a pandemic, not to mention save the lives of potentially millions of birds and protect the global supply of eggs and poultry.
Avian flu vaccines for birds could be one way to do that.
In 1994, Mexico became the first nation to vaccinate chickens against a strain of bird flu, and more than a dozen others have since followed suit, with China relying heavily on vaccination to protect its flocks.
US farmers have avoided avian flu vaccines for livestock due to issues with exporting poultry and eggs from vaccinated birds. Instead, as in many countries, they rely on culling to stop outbreaks if one bird tests positive, the entire flock is killed.
That could change, though.
Maybe its time to discuss vaccination.
In April 2023, the USDA began trialing several vaccines to protect birds against H5N1 2.3.4.4b, and the following month, the World Organisation for Animal Health an intergovernmental group focused on animal disease control suggested that vaccines should be considered.
Since almost every country that does international trade has now been infected, maybe its time to discuss vaccination, in addition to systematic culling which remains the main tool (to control the disease), Monique Eloit, WOAHs director general, told Reuters.
Vaccine development is slow going, though, with US Agriculture Secretary Tom Vilsack telling Congress in February 2024 that the USDA is probably 18 months or so away from identifying a vaccine that would be effective against the strain of avian flu thats currently spreading.
Even if the USDA does develop an effective vaccine for this strain, it then needs to work out the logistics of manufacturing and distributing the shots and then go through the process again for future strains.
Gene-editing offers a promising route towards permanent disease resistance.
A more radical idea for protecting poultry from avian flu is taking shape in the UK, where scientists are trying to use CRISPR to genetically engineer chickens that cannot catch the flu at all.
In 2023, the team announced that editing one gene stopped chickens from producing a protein that the avian flu virus uses to replicate itself inside cells. When intentionally exposed to the virus, just one out of 10 gene-edited birds was infected, and that one didnt spread the virus to any others.
The UK researchers suspect theyd need to make two more edits to the chickens to confer total immunity, and more research is needed to see how that might affect the health of the birds. If it proves safe and effective, though, the CRISPR approach could be a lasting solution to the bird flu problem in chickens.
Gene-editing offers a promising route towards permanent disease resistance, which could be passed down through generations, protecting poultry and reducing the risks to humans and wild birds, said Mike McGrew, the studys principal investigator, in October 2023.
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