Highlights

Several recent studies have provided additional evidence that standard food safety practices protect US consumers from H5N1 exposure. To reduce the risk of employees getting sick, PHC recommends businesses not offer raw milk in their food services. Businesses may wish to communicate the protection that pasteurization provides, as a recent survey showed fewer than half of US adults know that raw milk is less safe than pasteurized milk.

Survey: Majority of Americans do not understand the risks of raw milk

According to the Annenberg Public Policy Center’s latest health survey¹, only 47% knew drinking raw milk is less safe than drinking pasteurized milk. Also, 24% of Americans did not know that pasteurization is effective at killing bacteria and viruses in milk products. The germs in raw milk can cause foodborne illness with symptoms like diarrhea, stomach cramping, and vomiting. These infections can cause severe disease, hospitalization, or death.²

More evidence that food safety practices protect against H5N1

• FDA released a preprint of a study confirming that commonly used and FDA-approved continuous flow high temperature short time pasteurization process inactivates the H5N1 virus.³ Researchers collected bulk raw milk samples, tested these samples for H5N1, and then tested again after pasteurization. No infectious virus was present after pasteurization, providing evidence the milk supply is safe. Media reports have noted that 14% of the collected raw milk samples had infectious H5N1, but the study was not designed to assess prevalence of infectious H5N1 in raw milk.
• In a Journal of Virology research article, the authors collected 297 samples from 23 pasteurized dairy product types collected from 17 states.⁴ Of these samples, 20% had H5N1 viral segments detectable by quantitative real-time RT-PCR, but no infectious virus was detected in the samples. These results support earlier studies showing infectious virus is not present in pasteurized milk products.
• In a small study published in the Journal of Food Protection, the authors inoculated beef patties with a low pathogenic avian influenza as a proxy for the highly pathogenic H5N1 that has been circulating in US dairy cattle.⁵ Cooking the beef patties to the USDA FSIS recommended minimum internal temperature of 71.1°C reduced the presence of the virus to “below detection,” indicating recommended food safety practices significantly reduce risk of exposure to the virus.

References

1. https://www.annenbergpublicpolicycenter.org/public-fails-to-appreciate-risk-of-consuming-raw-milk-survey-finds/
2. https://www.cdc.gov/food-safety/foods/raw-milk.html
3. https://www.fda.gov/media/179708/download
4. https://pubmed.ncbi.nlm.nih.gov/38958444/
5. https://pubmed.ncbi.nlm.nih.gov/38958444/

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As grilling season heats up in the Northern Hemisphere, it is crucial to ensure meat is cooked to safe temperatures to prevent foodborne illness.

While H5N1 has not been identified in retail beef, the current H5N1 outbreak among dairy cows warrants taking additional precautions to ensure food safety. In a question-and-answer session with reporters, USDA scientists disclosed that existing safe cooking temperature recommendations for ground beef and steaks are adequate to prevent H5N1 exposure through food.

The USDA reported that hamburgers cooked to 120° Fahrenheit–the temperature of a rare steak–still contained traces of an H5N1 surrogate virus. The H5N1 surrogate virus was killed in hamburgers cooked to 145° F (medium) and 160° F (well done).1 While steaks are safe from other microbial contamination when cooked to 145° F, the USDA considers ground beef safe only when cooked to 160° F (well done). A complete list of safe minimum temperatures is available on the USDA website.

In addition to preventing possible H5N1 transmission, cooking meat to recommended temperatures helps prevent other foodborne illnesses caused by other viruses, bacteria, and parasites. An estimated 9.4 million cases of foodborne illness occur in the United States each year, and approximately 55,000 cases require hospitalization. Foodborne illnesses result in more than 1,300 deaths each year.²

For your safety, PHC strongly recommends using a food thermometer to ensure meats reach safe internal temperatures. This inexpensive and easy-to-use tool can significantly reduce the incidence of foodborne illnesses.

References

• 1. https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock/h5n1-beef-safety-studies
• 2. https://wwwnc.cdc.gov/eid/article/17/1/p1-1101_article

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On May 30, PHC published an analysis following articles in the Los Angeles Times¹ (May 13) and the San Francisco Chronicle² (May 28) that asked if high levels of influenza A in local wastewater systems were a sign of otherwise undetected avian influenza in people, livestock, or birds in those cities. Importantly, influenza A includes both seasonal influenza and H5N1 avian influenza. PHC concluded that avian influenza in California was extremely likely given its ubiquity among wild birds, but these cities’ distance from cattle herds and relatively low levels of influenza in wastewater made it extremely unlikely that avian influenza was driving the observed data. Instead, we believed local, human, seasonal influenza A activity drove the wastewater signal. Later data shown in a June 3 San Francisco Chronicle³ article confirmed this: only trace levels of avian influenza were detected in San Francisco wastewater in mid-May and could not be confirmed when the water was retested several days later. This article also highlighted the first detection of avian influenza in California this year - two chickens at a California live market.

Also on June 3, WastewaterSCAN,⁴ a joint monitoring system maintained by Stanford and Emory Universities, uploaded its first data on avian influenza detections across the United States during May. The California data was unremarkable, but the national data revealed compelling stories from several other areas across the United States. At the height of media attention during April-May, avian influenza was present at high concentrations in Iowa, Idaho, Minnesota, Michigan, and Texas. The limited number of sites covers a large geographical range and largely reflects areas with high cattle populations. The data indicate the likely extent of cattle infection, starting in January with the initial exposure event and propagating over the following months as infected animals moved around the country and spread the virus. These data are also consistent with a preprint research article posted in early May highlighting such movement based on genomic data.⁵

The data from Texas and Michigan are particularly compelling, while data collected in Idaho and Iowa was sparse and less conclusive. Collection site data is summarized below.

Texas Data:

• Sharp spikes were recorded at two wastewater testing sites in the Dallas metropolitan area.
• Peak levels were observed on May 20, when avian influenza accounted for nearly half of all influenza A detected.
• Throughout May, over 25% of influenza A at these sites was avian influenza, indicating early and ongoing virus shedding, likely from dairy cattle.

Michigan Data:

• Spikes were observed at three wastewater sites across the state: Jackson, Warren, and Traverse City.
• Peak levels were observed around May 23, when avian influenza accounted for 30-40% of all influenza A detected.
• Levels declined after the peak but remained over 30% for the rest of May.

Michigan Data:

• Notable spikes were noted in St Cloud (20% of influenza A), Red Wing (40%), and Mankato (48%) between May 22 and 24.
• The levels sharply declined after the initial spike.

What can we learn from this new data? First, the initial spikes in avian influenza detection, particularly in Texas, occurred before the substantial detections in dairy cows and milk which gained extensive media coverage in April and May. This timing once again highlights the importance of wastewater surveillance for tracking and responding to emerging infections. Second, and more concerning, the rapidity and range of these detections suggest a much broader distribution of avian influenza infection among cows over this period. Infections likely occurred across much of the country over a relatively short, 2-4 week period. While this outbreak in cattle has not posed a substantial threat to the general public or livestock, the rapid spread demonstrates how quickly a future pandemic could develop, and how difficult it would be to control.

The growing threat of avian influenza is real, especially as the disease becomes more entrenched in wild bird populations. The extensive interaction of infected wild birds with domestic animals, especially during migration, poses a substantial long-term threat to humans and livestock markets. The transit of livestock across the United States as part of the normal breeding, processing, and distribution cycle creates an easy way for disease to spread widely and quickly. It is essential for the United States to maintain a defensive posture against this emerging threat through intensive surveillance and comprehensive response plans to minimize the potential impact of future outbreaks. Businesses must maintain and regulaly update their pandemic and disruptive outbreak plans. See PHC's other recommendations in our April 26 analysis.

References

• 1. https://www.latimes.com/environment/story/2024-05-13/is-there-bird-flu-in-california-wastewater
• 2. https://www.sfchronicle.com/health/article/california-wastewater-h5n1-bird-flu-risk-19482460.php
• 3. https://www.sfchronicle.com/health/article/h5n1-avian-flu-san-francisco-19489217.php
• 4. https://data.wastewaterscan.org/
• 5. https://www.biorxiv.org/content/10.1101/2024.05.01.591751v1.full.pdf

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The detection of highly pathogenic avian influenza H5N1 in dairy cattle is a rapidly evolving multi-state outbreak. In the past week, Michigan has detected two human cases of avian influenza. PHC breaks down the implications below.

How do these two cases change the bigger picture?

For a novel influenza virus to cause a serious pandemic, the virus must be able to transmit between people and to cause severe disease. Last week’s Michigan case had a genetic change associated with greater virus replication and disease severity in mice.¹ This week's case had respiratory symptoms², meaning the virus was behaving more like a typical flu infection. Seasonal flu viruses are transmitted between people by replicating in the respiratory system and then spreading when someone coughs or exhales virus particles that infect others. While no person-to-person transmission is suspected in these cases, the changes in the virus are consistent with the kinds of changes required for spread between people.

How does this change the risk landscape for businesses?

For non-dairy-related businesses, these developments add urgency to the actions PHC has previously recommended (see "H5N1 in Dairy Cattle: What You Need to Know" from 5/9)

• Review your pandemic plan NOW, before there is an emergency.
• Evaluate planning for flu vaccine clinics on site in the fall. Note that if an H5N1 vaccine must be produced, it will be separate from the already formulated seasonal flu vaccine.
• Maintain or establish a work culture that supports employees’ decisions to wear masks.
• Maintain or increase the budget for cleaning supplies and hand sanitizer to avoid unexpected costs.
• Businesses that provide food services should plan for the price of milk and eggs to fluctuate when developing budgets.

Dairy-related businesses should evaluate their personal protective equipment practices for workers exposed to raw milk. While adoption of PPE provides the greatest worker protection, summer weather can make PPE challenging to utilize. If regular use is not achievable, businesses should minimally consider selective adoption of PPE when H5N1 is suspected due to symptoms in cattle, humans, cats, or other mammals.

Is Michigan a hot spot for H5N1?

Michigan’s strong active surveillance³ is likely producing better detection of H5N1 in both humans (2 cases) and dairy herds (22 of the 69 infected herds in the US)⁴ than in other US states.

Why is the latest case described as an H5 infection and not H5N1?

The tests for the neuraminidase (the N in the subtype) are pending genetic sequencing at CDC.

References

• 1. https://www.cdc.gov/flu/avianflu/spotlights/2023-2024/h5n1-technical-update-may-24-2024.html
• 2. https://www.cdc.gov/media/releases/2024/p0530-h5-human-case-michigan.html
• 3. https://www.michigan.gov/mdard/about/media/pressreleases/2024/05/01/mdard-director-signs-hpai-risk-reduction-response-order-for-hpai-outbreak-animal-health-emergency
• 4. https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock

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Key Points

• Based on PHC's internal analysis, the elevated influenza A concentrations in San Francisco Bay Area wastewater do not indicate any immediate threat of avian influenza infection in humans; the signal is likely driven by human seasonal influenza infection.
• While we cannot rule out contamination from agricultural runoff or entirely exclude the contribution of avian influenza without sequencing data, influenza A levels in local wastewater are within reasonable margins given local seasonal flu activity.
• Current and future infection of California cattle herds with avian influenza remains highly probable.

Background

Earlier in May, an article in the Los Angeles Times considered whether elevated influenza A activity in local wastewater was potentially due to otherwise undetected avian flu transmission.¹ On Tuesday evening, a similar article ran in the San Francisco Chronicle,² citing ongoing elevated levels of influenza A in Bay Area wastewater, speculated if avian influenza activity—particularly in local dairy cows—may be behind the increase.

Analysis

Consideration #1: This year's flu season has been marked by lingering case activity throughout the United States, with California continuing to report some of the highest influenza infection rates.³ Compared to the height of flu season, California's infection rates are substantially lower, as is the influenza A wastewater signal, which traditionally lags behind case and hospitalization data. Lastly, wastewater data is highly variable, and increases may be an artifact of the data.

Consideration #2: California's Central Valley is home to some of the country's most dense dairy cattle populations. The runoff from the farms housing these cattle follows the Bay Delta watershed and ultimately empties into the San Francisco Bay, raising the possibility that some of the influenza A signal we are observing in the San Francisco area may be due to runoff from these farms or the dumping of milk from infected cows. However, given the journey and amount of dilution that would occur between those farms and the sampling sites, a sizable H5N1 outbreak would need to occur to drive the observed trends in wastewater data, which PHC believes is unlikely.

Conclusion

It is unlikely that the elevated influenza A activity in the Bay Area wastewater indicates substantial human exposure to avian influenza. However, avian influenza in mammalian populations, including humans, is a serious and growing public health concern. Diligent surveillance activities and ongoing wastewater testing are essential to address this growing threat. PHC continues to track data and will provide clarity on the H5N1 threat.

References

• 1. https://www.latimes.com/environment/story/2024-05-13/is-there-bird-flu-in-california-wastewater
• 2. https://www.sfchronicle.com/health/article/california-wastewater-h5n1-bird-flu-risk-19482460.php
• 3. https://www.cdc.gov/flu/weekly/usmap.htm

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Hong Kong’s ban on poultry imports from some countries does not reflect a change in the threat posed by food and is a reminder that these actions can be issued for both safety and political reasons.

On Monday, the Centre for Food Safety in Hong Kong announced a ban on poultry meat and egg imports from several countries, including the US, citing the risk posed by H5N1 avian influenza.¹ Within hours, Macau, another special administrative region of China, issued a similar announcement which, while not as direct as Hong Kong’s announcement, also implied an immediate ban on US poultry imports.²

These bans follow the recent announcement of a human fatality from another strain of avian influenza in mainland China’s Fujian province³, and occur during a period of heightened global attention to the ongoing threat of avian influenza in poultry, livestock, and humans, which has led to other import bans, including a US ban on poultry imports from areas of Australia announced last week.⁴

There is historical precedent for these sorts of actions. In 2015, following a similar period of heightened global awareness of avian influenza, Hong Kong announced a comparable ban of US poultry products⁵ which was part of a broader Chinese ban of US poultry products. The restrictions lasted nearly 5 years, far exceeding the period of heightened bird flu activity used to justify the ban.⁶ Since then, China has issued numerous shorter bans on poultry imports during periods of US avian influenza outbreaks. While Chinese imports of US poultry products accounts for less than 1% of US to China export value, it does equate to over $1 billion annually for US farmers.⁷

At present, this action is limited and may be temporary. However, based on the nature of US-China trade relations, the risk does still exist for these restrictions to escalate into a broader and more lasting ban. It is important to reiterate that, while long-term public health risk from avian influenza is real and growing, immediate risk from the food supply is small. When infected chickens are handled properly, the risk of avian influenza entering the food chain is negligible⁸ and there is no evidence to date that consumption of contaminated poultry products can lead to disease in humans.⁹

Lastly, import bans are sometimes used for political reasons. In addition to protectionism, import bans can frame a disease as a foreign threat to the domestic audience. Given that Hong Kong’s 1997 H5N1 cases represent the first example of a purely avian virus causing respiratory disease and death in humans¹⁰, the new ban is inconsistent with the known ecology of avian influenza viruses.

References

• https://www.info.gov.hk/gia/general/202405/27/P2024052700473.htm?fontSize=1
• https://www.gov.mo/zh-hant/news/1066966/
• https://www.cidrap.umn.edu/avian-influenza-bird-flu/china-reports-fatal-h5n6-avian-flu-case-0
• https://www.abc.net.au/news/rural/2024-05-25/united-states-of-america-bans-victorian-poultry-products/103893610
• https://www.cfs.gov.hk/english/press/20150122_0152.html
• https://southernagtoday.org/2023/09/07/the-rise-and-fall-of-u-s-chicken-feet-in-china-a-story-of-bird-flu-and-trade-bans/
• https://oec.world/en/profile/bilateral-country/usa/partner/chn
• https://www.fda.gov/food/egg-guidance-regulation-and-other-information/questions-and-answers-regarding-safety-eggs-during-highly-pathogenic-avian-influenza-outbreaks
• https://www.annualreviews.org/deliver/fulltext/food/2/1/annurev-food-022510-133710.pdf?itemId=/content/journals/10.1146/annurev-food-022510-133710&mimeType=application/pdf
• https://www.pnas.org/doi/full/10.1073/pnas.132268999

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A recent preprint study of cow tissue may bode well for the beef industry and explain the unusual way that H5N1 appears to spread among dairy cows in the United States.1

Researchers studied various tissues present in dairy cows and identified that memory gland tissue–such as that found in a cow udder–contained a large number of the cell receptors that H5N1 binds to. Equally important, the study found low numbers of these H5N1 binding sites in respiratory and brain tissue.

These biological findings support the hypothesis that H5N1 is transmitted among cows by infected milk – likely small amounts of infected milk remaining on milking equipment. These findings also help explain why the most significant symptoms of H5N1 infection in dairy cows –mastitis and a drop in milk production–are unrelated to the respiratory and neurological systems, where H5N1 has previously been documented.

The beef industry should take notice of these findings. The 2.3.4.4b strain of the virus–in the absence of commercial milking equipment–may be hard to transmit between dairy cows and beef cattle or among beef cattle due to the low numbers of H5N1 receptor sites in the respiratory tract.

References

• https://www.biorxiv.org/content/10.1101/2024.05.03.592326v1

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The detection of highly pathogenic avian influenza H5N1 indairy cattle is a rapidly evolving multi-state outbreak. In this analysis, PHC assesses the current situation and describes low-effort actions to take now. Details for each bullet are available at the end of the analysis.

Brief Overview:

In March 2024, highly pathogenic avian influenza (HPAI) H5N1 was detected in adairy herd in Texas. In the following weeks, 33 herds in 8 states tested positive for H5N1.¹ This week, viral fragments were found in grocery store milk. HPAI H5N1 has been devastating to poultry operations for several years. Before the current strain emerged, H5N1 had a roughly 50% mortality rate in humans, but the current strain (H5N1 2.3.4.4b) typically causes mild disease in people. The current outbreaks in cattle do not pose an immediate threat to employee safety or work continuity for enterprise businesses, but the situation is rapidly evolving. PHC details low-effort actions businesses can take now to prepare for potential shifts in the virus behavior.

PHC's assessment:

• H5N1 has been circulating in cows for many months. [Strong evidence]
• H5N1 genetic material is present in grocery store milk. [Strong evidence]
• Infectious H5N1 is not present in grocery store milk. [More evidence needed]
• Human infection with this H5N1 is often but not always mild. [More evidence needed]
• Person-to-person transmission of H5N1 is currently rare. [Strong evidence]
• Human infection with this strain of H5N1 is rare. [Not well investigated]
• H5N1 is susceptible to commercially available antiviral medicines used to treat seasonal influenza. [Strong evidence]
• Existing processes and manufacturing platforms can be used to jump start the development of a human vaccine against H5N1 if needed. [Strong evidence]
• PHC predicts restrictions on and testing requirements for dairy cattle movement will continue to evolve. [High confidence]

Unanswered questions:

• How did the first infection in a cow occur?
• How is H5N1 transmitted between cows and from cows to humans?
• How widespread is the outbreak?
• How feasible is it to control H5N1 transmission within commercial farms?

Actions your business can take now:

• Review your pandemic plan NOW, before there is an emergency.
• Evaluate planning for flu vaccine clinics on site in the fall.
• Maintain or establish a work culture that supports employees’ decisions to wear masks.
• Maintain or increase the budget for cleaning supplies and hand sanitizer to avoid unexpected costs.
• Businesses that provide food services should plan for the price of milk and eggs to fluctuate when developing budgets.

Evidence evaluation:

Strong evidence:The statement is well supported by publicly available data and established scientific knowledge. More evidence needed:The statement is supported by evidence, but additional data is still needed (e.g., more testing required). Not well investigated:The statement has some evidence to support it, but significant gaps exist. Conflicting evidence:The statement has conflicting evidence, so more evidence is needed before drawing conclusions.

Additional details for items above:

H5N1 has been circulating in cows for many months. [Strong evidence]

On April 21, USDA released 249 genomic sequences² to GISAID (the Global Initiative on Sharing Avian Influenza Data). Michael Worobey is a world-renowned expert inviral genomics who uses molecular and computational biology to understand how pandemics emerge and spread. Worobey’s team immediately analyzed the published sequences. Their analysis indicates the time of the most recent common ancestor (TMRCA) of the US cattle flu clade was late December,³ meaning this version of H5N1 has been circulating for months. Louise Moncla's labat the University of Pennsylvania found similar results.⁴

H5N1 genetic material is present in grocery store milk. [Strong evidence]

On April 23, the FDA reported that tests on grocery store milk had found genetic material from the same H5N1 virus identified in the sick dairy cattle.⁵ Quantitative polymerase chain reaction (qPCR) is a molecular biology technique used to determine the presence or absence of an organism’s DNA in a sample. The tests can identify pieces of the virus, which can be present even if the virus has been inactivated.

Andrew Bowman, a veterinary epidemiologist at Ohio State University, collected 150 commercial milk from 10 states. Using PCR, his team found 58 tested positive samples.⁶

The discovery of H5N1 genetic material raises two questions. First, how widespread is the outbreak? The presence of H5N1 genetic material in milk may indicate that many more herds are impacted than known herds suggest. Secondly, are some infected cows not developing symptoms? If the cow appears well, dairy farms may not suspect infection and continue to milk the cow as usual.

Infectious H5N1 is NOT present in grocery store milk. [More evidence needed]

Although tests have detected the presence of viral H5N1 fragments in milk, that isnot necessarily a cause for alarm. Pasteurization ⁷ is likely to inactivate (kill) the virus but is not expected to remove inactive viral fragments from the milk.

Studies of pasteurization and virus inactivation ⁸ indicate pasteurization should inactivate H5N1. Pasteurization was developed primarily to address the threat of infectious bacteria. Bacteria are typically much hardier than viruses. Additionally, influenza viruses are enveloped viruses and are more susceptible to heat and changes in pH.

Additional tests are being performed to confirm that these viral fragments are not capable of causing infection. Laboratory tests in which viral fragments are transferred to eggs to see if they can infect the eggs are currently in progress; the results of these tests are expected over the next few days.

Human infection with this H5N1 is often but not always mild [More evidence needed]

The US has identified two human cases of H5N1 in the past two years. The most recent case is a worker on the Texas dairy farm where H5N1 was identified; their only symptom was conjunctivitis. The other US case occurred in April 2022 in a person culling infected commercial poultry; they reported fatigue. Both cases recovered.

Internationally, several people have been infected with this H5N1 strain, including 5 asymptomatic cases in the UK and 2 asymptomatic cases in Spain. Chile, China,and Ecuador have reported a total of 4 severely ill cases with 1 death. Historically, other H5N1 strains have caused severe illness and high death rates in humans. Notably, H5N1 2.3.2.1c caused 4 illnesses (3 of them fatal) in Cambodia last year.⁹

Person-to-person transmission of H5N1 is currently rare. [Strong evidence]

H5N1 does not have mutations that support easy person-to-person transmission. Between 2004 and 2007, there were rare non-sustained instances of human-to-human transmissions that most likely occurred between family members with prolonged close exposure to a sick individual. Those cases involved earlier strains. The current H5N1 2.3.4.4b strain did not emerge until 2020.

Over time, the virus may acquire mutations that make person-to-person transmission more efficient, reinforcing the need for effective interventions to control and monitor transmission in livestock, commercial flocks, and wild birds.

Human infection with this H5N1 is rare. [Not well investigated]

As of April 25, the CDC has tested 23 people for H5N1, is actively monitoring 44 people, and is passively monitoring additional people. Only one case has been detected. Anecdotally,¹⁰ people in the bovine industry have observed sick people where there have been sick cows; however, it is also winter respiratory illness season, which may explain the illnesses. Because people are not regularly tested for H5N1, mild cases may have gone undetected.

H5N1 is susceptible to commercially available antiviral medicines used to treat seasonal influenza. [Strong evidence]

This week, the CDC concluded tests indicating that two classes of antiviral medications used to treat seasonal influenza are effective against H5N1. Neuraminidase inhibitors (e.g., oseltamivir (Tamiflu®), zanamivir, and peramivir) and polymerase inhibitors (e.g., baloxavir (Xofluza®)) can be used against H5N1. [Study results were shared at a symposium with PHC staff in attendance.]

The US maintains a Strategic National Stockpile (SNS)¹¹ of several medications, including all the antivirals discussed above. These tens of millions of courses of antivirals can be used to supplement commercial sources and alleviate supplychain issues should they arise. No supply chain issues have been noted so far for these antiviral medications. During the 2022-2023 flu season, the early peak caused spot shortages, and the SNS remedied the deficit. If needed for H5N1, the SNS could follow the same operational plan used for that shortage.

Existing processes and manufacturing platforms can be used to jumpstart the development of a vaccine for H5N1 if needed. [Strong evidence]

Vaccination of humans against H5N1 is not a tool that is required at this time, but the preparedness steps are in place to develop vaccines and plans for administration. The CDC constantly monitors for emerging types of influenza. When they identify viruses that are sufficiently new or concerning in any way, they create candidate vaccine viruses. These are blueprints for a potential vaccine target. The National Pre-pandemic Influenza Vaccine Stockpile (NPIVS)¹² program takes these candidates and completes the initial manufacturing of a potential vaccine. Completing this process before the vaccine is needed allows them to address manufacturing issues and build an initial vaccine supply. NPIVS also stockpiles other components of the vaccines to allow for rapid manufacturing.

Two H5N1 candidate vaccine viruses are well matched to the H5N1 in dairy cattle. NPIVS has completed an initial fill of some vaccine doses and is evaluating the appropriate regulatory pathway for use if they are needed for response. These hundreds of thousands of doses would be the initial rollout. A second wave woulduse stockpiled components to create up to 10 million doses. If more doses are needed, existing US government contracts with manufacturers would be leveraged for large-scale manufacturing. The current preparedness is covered as normal activities in the US budget; switching to a response posture would require additional funding from Congress.

PHC predicts restrictions on and testing requirements for dairy cattle movement will continue to evolve. [High confidence]

Numerous US states ¹³ have restricted cattle imports from states with H5N1 outbreaks. USDA will require dairy cattle to have a negative Influenza A result for interstate travel.¹⁴ As of April 5, The World Organisation for Animal Health (WOAH) did not recommend import restrictions on cattle or dairy products.¹⁵ WOAH recommendations have wide-reaching impacts. All countries that are members of the World Trade Organization agree to abide by WOAH assessments regarding import restrictions. ¹⁶An import risk analysis must be conducted according to WOAH Terrestrial Animal Health Code Chapter 2.1. Despite this requirement, on April 25, Colombia became the first country to restrict US beef exports.¹⁷

Actions your business can take now:

Review your pandemic plan NOW, before there is an emergency.

The outbreak of H5N1 in dairy cattle serves as a reminder that new infectious disease outbreaks are inevitable. Companies should plan to review their pandemic plans yearly and when potential threats emerge. Ensure that personnel information reflects changes due to staff turnover or contact information changes. Be clear on how decisions will be made regarding office closures,changes to remote work policies, cleaning schedules, and provision of supplieslike hand sanitizer and masks.

Evaluate planning for flu vaccine clinics on site in the fall.

On-site flu shot clinics reduce barriers to employees getting annual vaccinations for seasonal flu. Last year, some employers reported difficulty securing practitioners for on-site flu clinics. Early contracting with these clinics can help ensure your employees are protected against seasonal influenza. If H5N1 evolves to spread easily between humans, an additional flu vaccine may be developed (as happened in 2010 during the H1N1 pandemic). On-site flu clinics could be used to provide both seasonal and H5N1 vaccines if warranted.

Maintain or establish a work culture that supports employees’ decisions to wear masks.

Masks can be effective at preventing influenza and other infections. Individuals who are vulnerable or who have vulnerable family members may prefer to wear masks to reduce the risk of numerous airborne infections. A work culture that supports those decisions can make it easier for other employees to add this layer of protection if the risk rises. Reducing infections protects workers’ health, reduces absenteeism, and can reduce employer health insurance costs.

Assess the budget for items like cleaning supplies and hand sanitizer to avoid unexpected costs. Plan to restock early to avoid any shortages that develop.

The current situation is not a crisis; businesses should not over invest in stockpiling. Nevertheless, the current outbreak introduces uncertainty around the demand forthese products, and businesses should consider the cost of additional storage versus potential future order delays. Increasing the cadence for reviewing purchasing schedules may suffice during this early stage.

Businesses that provide food services should plan for the price of milk and eggs to fluctuate when developing budgets.

H5N1 outbreaks in US poultry have repeatedly resulted in significant losses of commercial poultry. The culling of egg-laying flocks has previously driven egg prices to record highs. The spring avian influenza season is starting, and egg prices are currently up 16% from January. Numerous industry publications predicted egg prices would not climb above 2023 prices, but avian influenza impacts remain unpredictable.

By comparison, infected dairy cattle appear to fully recover after about two weeks, a limited period of the cow’s overall milking days. Currently, the outbreaks are too limited to impact the availability of milk in the US. Cattle live longer and are far more expensive than poultry. Therefore, culling will not be an initial step in control. Mandatory testing or other interventions may add costs to milk production that are eventually passed down to the consumer (although USDAAPHIS will compensate farmers for the cost of H5N1 testing for diagnostics or travel if performed at a National Animal Health Laboratory Network lab). Consumer reaction to the discovery of H5N1 genetic material in grocery store milk may have a larger impact on the industry.

References

1. https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock 2. https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/usda-publishes-h5n1-influenza-virus-genetic 3. https://twitter.com/MichaelWorobey/status/1782756133402509587 4. https://twitter.com/LouiseHMoncla/status/1783555179180356093 5. https://www.fda.gov/food/alerts-advisories-safety-information/updates-highly-pathogenic-avian-influenza-hpai 6. https://www.science.org/content/article/u-s-government-taking-action-stop-cow-flu-it-too-little-too-late 7. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=131.3 8. https://pubmed.ncbi.nlm.nih.gov/32650645/ 9. https://www.cdc.gov/flu/avianflu/spotlights/2022-2023/h5n1-technical-report_october.htm 10. https://www.bovinevetonline.com/news/industry/message-ag-industry-about-h5n1 11. https://aspr.hhs.gov/SNS/Pages/Access-to-Influenza-Countermeasure.aspx 12. https://medicalcountermeasures.gov/barda/influenza-and-emerging-infectious-diseases/pandemic-vaccines-adjuvants/ 13. https://www.avma.org/news/states-begin-restrict-cattle-imports-those-influenza-cases 14. https://www.usda.gov/media/press-releases/2024/04/24/usda-actions-protect-livestock-health-highly-pathogenic-h5n1-avian 15. https://www.woah.org/en/high-pathogenicity-avian-influenza-in-cattle/ 16. https://www.wto.org/english/thewto_e/coher_e/wto_oie_e.htm 17. https://www.reuters.com/markets/commodities/colombia-becomes-first-country-restrict-us-beef-due-bird-flu-dairy-cows-2024-04-25/

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Examination of genomic sequences points to a single viral introduction from birds to dairy cows.²This specific H5N1 has mutations that allowed researchers to identify its reintroduction into wild migratory birds. Spillback into migratory birds–or wild mammals–introduces the possibility of the dairy cattle H5N1 strain spreading throughout the United States and to additional countries. Migratory birds have spread earlier versions of H5N1 along their flyways, allowing new viruses to travel the world within two years.³

Contaminated milking equipment is suspected of transmitting H5N1 between dairy cows, and the movement of dairy cattle can introduce the virus to new farms.⁴ Because dairy and beef operations are separate, dairy cows are unlikely to spread H5N1 to beef cattle directly. However, the fact that H5N1 was introduced to dairy cows does not eliminate the possibility of a future introduction to beef cattle. Understanding more about the mechanism by which H5N1 spreads between dairy cows is critical to understanding the possible impacts of H5N1 to beef cattle. Dairy cattle appear to recover fully after infection, with limited lost milking days. For beef cattle, a similar impact could be less efficient weight gain.

Agricultural businesses and businesses sensitive to the cost of poultry and cattle products should prepare for the possibility of H5N1 spreading to cattle beyond the United States. While pasteurization of dairy products and proper cooking of meat can ensure food safety, testing or treatment could increase production costs that may be passed to consumers.

The overall risk from H5N1 to the public is currently low. Because this strain of H5N1 does not spread readily from person-to-person, individuals working closely with birds and cows remain at the highest risk of infection. However, more research is needed to determine how transmissible this strain is from cows to humans. Ongoing genomic surveillance of H5N1 in cattle will be necessary to detect changes with implications for human health.

PHC will update this assessment as conditions change.

References

• 1. https://media.un.org/unifeed/en/asset/d320/d3202385
• 2. https://twitter.com/MichaelWorobey/status/1782756133402509587/photo/1
• 3. https://www.sciencedirect.com/science/article/pii/S0006320723001428#f0005
• 4. https://www.science.org/content/article/bird-flu-may-be-spreading-cows-milking-and-herd-transport

Confidential and Proprietary

PHC Global provides this material for informational purposes only. It does not constitute, and is not asubstitute for, medical services or advice and should not be construed as such.

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