Friday, September 11, 2026

South Korean CDC Issues Early Seasonal Flu Epidemic Advisory


Proportion of Suspected Influenza Cases in Clinics
( As of Sep 5, 2026 ; Persons / 1,000 Persons )

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Typically, nations in the Northern Hemisphere don't even begin tracking seasonal  influenza seriously until October 1st; the assumed start of each year's flu season.  Our own CDC only publishes an abbreviated  FluView report during the summer months (see Week 20 2026 notice below).

Two weeks ago (Aug 28th), however, Japan announced the earliest start since the 2009 H1N1 pandemic for their flu season (see Japan MHLW Reports Unusually Early Start to the Fall Flu Season), while Taiwan reported this week `. . . emergency room visits reached 11.2%, exceeding the epidemic threshold (11.0%), indicating the start of the epidemic period.'

This unusual wave of early flu continues, as today South Korea's CDC issued an early seasonal flu advisory, citing a 4x higher rate of ILI (Influenza-like Illness)  consultations this week than a year ago. 

        (translation)

Date written 2026.09.11
Last modified date 2026.09.11
Department in charge Infectious Disease Control Division
contact 043-719-7141

Influenza Epidemic Advisory Issued for 2026-2027 Season; Early-than-usual Outbreak, Response Strengthened for Students and High-Risk Groups

- With the start of the season, “2026-2027 Season Influenza Epidemic Advisory Issued” starting September 11 (Fri)

- Although COVID-19 levels are lower than the same period last year, the number of hospitalized patients continues to increase

- Conducted a review of the epidemic status and response measures together with experts and relevant ministries

Emphasize wearing a mask when experiencing respiratory symptoms and urge adherence to preventive measures against respiratory infections, such as covering the mouth and nose with a tissue or sleeve when coughing; high-risk groups need to visit a medical institution early for appropriate treatment if they experience fever or respiratory symptoms.

The Korea Disease Control and Prevention Agency (Director Lim Seung-kwan) announced that, as the incidence of influenza is higher than in previous years, it held the "9th Meeting of the Inter-Ministerial Joint Task Force on Respiratory Infectious Diseases" with medical experts and relevant ministries (Ministry of Health and Welfare, Ministry of Food and Drug Safety, Ministry of Education) to review the current status of influenza and COVID-19 outbreaks and response measures, and issued an "Influenza Epidemic Advisory" starting at 00:00 on September 11 (Fri).

(Criteria for issuing an epidemic advisory for the '26-'27 season) Issued following expert consultation when the proportion of suspected influenza (ILI) cases exceeds the epidemic threshold for the relevant season and the influenza virus detection rate is 5% or higher.

※ Influenza-like illness (ILI): Cases where a cough or sore throat is present along with a fever of 38°C or higher

【 Current Status of Influenza and COVID-19 Outbreaks 】

According to the results of the sample surveillance of influenza-like illness (ILI) at clinics, the proportion of influenza-like illness cases in the 36th week of 2026 (Aug. 30–Sept. 5) was 25.3 per 1,000 outpatients, exceeding the epidemic threshold for this season (12.9) and rapidly increasing to a high level compared to the same period last year (6.6).
* (ILI rate over the last 4 weeks) Week 33 7.5 → Week 34 9.2 → Week 35 13.3 → Week 36 25.3

※ The influenza surveillance system operates from week 36 to week 35 of the following year (September to August of the following year) as a single season.
Incidence is increasing across all age groups, with a relatively high and rapid increase observed in the school-age and infant/child age groups, in the order of 7-12 years (75.1 people), 1-6 years (49.8 people), and 13-18 years (31.3 people).
* 7-12 years (75.1 people) > 1-6 years (49.8 people) > 13-18 years (31.3 people) > 0 years (24.0 people) > 19-49 years (23.5 people) > 50-64 years (11.8 people) > 65 years and older (8.8 people)
The number of inpatients at sample medical institutions at the hospital level in week 36 was 300, which is about double the number from last week (166) and shows a higher incidence compared to the same period last year (23 in week 36 of '25), and the age group of inpatients aged 65 or older accounts for the largest proportion at 60.0%.
* (Number of hospitalized patients in the last 4 weeks) Week 33: 78 → Week 34: 89 → Week 35: 166 → Week 36: 300
The detection rate of influenza viruses is also showing an increasing trend*, and the influenza virus currently in circulation is Type A (H1N1) pdm09, which is similar to the vaccine strain for this season** and has been confirmed to have no mutations affecting resistance to treatment.

* (Detection rate over the last 4 weeks) Week 33 5.4% → Week 34 10.0% → Week 35 12.3% → Week 36 16.3%
**The virus used to produce the influenza vaccine recommended by the World Health Organization (WHO)


(SNIP)

The Korea Disease Control and Prevention Agency plans to sequentially implement the national influenza vaccination program starting Monday, September 21, but it also plans to review measures to adjust the vaccination schedule, focusing on high-risk groups including immunocompromised individuals, by comprehensively considering the epidemic situation and vaccine supply schedule.

(Continue . . . )

Many countries won't begin to ramp up their fall flu vaccination campaigns until October (see UKHSA blog), and as cited above, South Korea's target date is still 10 days away. 
 
Given that this year's fall flu vaccines have been updated to reflect recent antigenic changes observed in all 3 seasonal flu types (see WHO Recommendations for Influenza Vaccine Composition), community immunity against this fall's array of circulating flu viruses may be low.  

Complicating matters, South Korea is also reporting low, but rising, rates of COVID infection:

In addition, the number of COVID-19 inpatients at hospital-level sample surveillance medical institutions in the 36th week of 2026 (Aug. 30–September 5) was 193, which is lower than the same period of the previous year (433 in the 36th week of 2025), but has been continuously increasing since August, and by age group, the elderly aged 65 or older accounted for the largest proportion at 65.3% of the total.

* (Number of hospitalized patients in the last 4 weeks) Week 33: 57 → Week 34: 61 → Week 35: 115 → Week 36: 193

COVID wastewater surveillance (see chart below) shows increasing detection in sewage.


While none of this tells us much about the severity of this year's flu season, it does suggest that it may be upon us sooner than we expect.  Of course, what happens in Asia isn't necessarily a harbinger for what we see in North America or Europe, but it is definitely worthy of our attention. 

The U.S. CDC should publish their updated Respiratory Virus Activity Levels report later today, but last week's report showed very little flu, and low, but rising COVID activity. 

 

Stay tuned. While things are quiet now, it could be a bumpy fall. 
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Thursday, September 10, 2026

The Lancet Regional Health Europe (Comment): If the EU is serious about One Health, it must ban fur farming


#19,329

Last month, in That Touch of Mink Flu (H5N1 in Utah Edition), we looked at the latest report of an avian flu virus detected in 7 captive (presumably farmed, but details are scant) mink here in the United States.  

This time, the viral culprit was avian H5N1, but over the years we've followed numerous reports of zoonotic pathogens detected on fur farms, with some even spilling over into humans.  

While mink are most frequently cited, fox, raccoon dogs, and rabbits are also farmed.  Some early reports include:

It was in 2020, however, when a unique mink-variant of SARS-CoV-2 was discovered spreading through millions of farmed mink in Denmark - which then jumped to humans - that the alarm bells were really raised (see EID Journal: SARS-CoV-2 Transmission between Mink (Neovison vison) and Humans, Denmark).

This prompted authorities to order the depopulation of 17 million mink (see Denmark Orders Culling Of All Mink Following Discovery Of Mutated Coronavirus), to temporarily lock down North Jutland (where most of the human cases had been identified) and led to some countries banning travel to and from Denmark.
 
Denmark wasn't alone, as fur farms in Spain, the United States, Canada, and several other European countries all eventually reported outbreaks of COVID, with some evidence of spillovers into humans (see CDC: Investigating Possible Mink-To-Human Transmission Of SARS-CoV-2 In The United States).

Alarms were raised again in the fall of 2022 when H5N1 began spreading rapidly through a large mink farm in Spain (see Eurosurveillance: HPAI A(H5N1) Virus Infection in Farmed Minks, Spain, October 2022).

This mink-derived H5N1 virus from Spain carried a rare mutation (PB2-T271A), which is believed to `enhance the polymerase activity of influenza A viruses in mammalian host cells and mice'. In 2023 the CDC issued an IRAT Risk Assessment On Mink Variant of Avian H5N1, finding its scores had risen in 6 of the 10 parameters used to evaluate their zoonotic potential.

The following year (2023) Finland's fur industry was hit unusually hard by HPAI H5N1, with more than 70 fur farms infected, and > 500,000 animals culled, prompting  Finland's Institute for Health and Welfare (THL) to warn `Avian influenza poses a risk to public health – improvements to health security needed at fur farms'.

During the height of this outbreak, we looked at an excellent opinion piece (see PNAS: Mink Farming Poses Risks for Future Viral Pandemics) penned by two well known virologists from the UK (Professor Wendy Barclay & Tom Peacock) on why fur farms - and mink farms in particular - are high risk venues for flu.

Since then we've seen several other notable outbreaks, including SFTS in Chinese Farmed Mink and a reassorted swine and human-origin H3N2 in Canadian farmed mink.  Many farms, and governments, are reluctant to provide details on outbreaks, and so we are likely only seeing the tip of the iceberg. 

While some EU countries have taken steps to phase out or ban fur farming, the industry continues in many parts of the world, including China, Russia, the United States, Canada and parts of the EU.

All of which brings us to a commentary, published two weeks ago in The Lancet Regional Health: Europe, which calls upon the EU to ban fur farming due to the public health risks they pose. 

If the EU is serious about One Health, it must ban fur farming
Joanna Swabea Send email to jswabe@humaneworld.org ∙ Chris Walzerb,c ∙ Benjamin Roched,e ∙ Arnaud Fontanetf ∙ Thijs Kuikeng ∙ Manon Lounnasd ∙ et al. 
Received August 4, 2026; Accepted August 20, 2026; Published August 29, 2026
DOI: 10.1016/j.lanepe.2026.101848 External Link 
Copyright: © 2026 The Author(s). Published by Elsevier Ltd.
User License: Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0) | Elsevier's open access license policy

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The One Health approach, which recognises the fundamental interconnectedness of human wellbeing with that of other animals and the environment, is a keystone of the European Union’s health policy.1 While the prevention of zoonotic diseases, including pandemics, is a core objective of this policy, the European Commission paradoxically seems reluctant to take decisive action to address one of the highest risk sources within its borders precisely at the moment when it finally can do so. 
Specifically, the Commission is currently considering legislation to ban fur farming in the EU, prompted by a 2023 European Citizens’ Initiative on the issue that had the support of more than 1.5 million EU citizens.2 A decision was due by March 2026, but the Commission has thus far delayed issuing one. There are indications that it may instead propose minimum welfare standards for the intensive production of fur-producing animals.2 However, doing so would be a grave mistake for animals and humans alike.

Fur farming is a niche industry producing non-essential luxury products, yet it poses a threat to human health. It is an avoidable anthropogenic system that concentrates large numbers of genetically homogeneous, susceptible wild fur-bearing animals in close confinement creating the conditions that favour the introduction, amplification, adaptation and spillover of pathogens to humans (spillover being the transmission of a pathogen from one vertebrate species to another).3 Once a pathogen is introduced to captive animals on these farms (whether from humans, contaminated feed, or from wildlife attracted to the farms), it can spread easily and eventually infect humans working on these farms.3

Fur farms have already been implicated in serious outbreaks in multiple countries across Europe. In 2020, for example, mink became infected with SARS-CoV-2 on multiple mink farms in the Netherlands, with subsequent “spillback” of SARS-CoV-2 from mink into humans.4 SARS-CoV-2 outbreaks were also identified on 290 mink farms in Denmark, resulting in hundreds of COVID-19 cases in humans caused by mink variant strains.5 The Danish government responded by culling the country’s entire farmed mink population — 17 million animals — while compensating mink farmers over €3 billion for their losses.6,7 It also suspended mink farming activities, but these have since resumed.

Lessons learned?
The lesson learned from COVID-19 was not that more surveillance could make fur farms safe, but rather that surveillance documented the predictable consequences of a production system that facilitates pathogen introduction, amplification and adaptation. This cyclical reactive response followed by a return to business as usual reflects a pervasive global health security framework that is unsustainable. One Health is fundamentally about investing upstream, reducing the conditions that give rise to disease emergence rather than continually paying for downstream surveillance and response, after damage is already done. Continuing to invest public resources in managing risks generated by an economically failing niche industry is difficult to reconcile with the EU’s preventive One Health ambitions.7

Outbreaks of highly pathogenic avian influenza A(H5N1) have also affected fur farms. In 2023, infections were confirmed on multiple fur farms in Finland, likely introduced to captive animals from wild birds.8 Spain also recorded an H5N1 outbreak on a mink farm in 2022, with possible viral mutation on the farm.9 An especially concerning aspect of influenza in mink is that they are susceptible to influenza viruses originating from both birds and humans. They can therefore serve as a host in which genetic reassortment occurs, which is a known route for the evolution of influenza viruses that can cause pandemics.3

These outbreaks have accelerated the decline of the EU fur farming industry. By 2024, fur production had dropped to an annual low of 6.3 million pelts, corresponding to €183 million in sales — a decline of 92% compared with the previous decade.7 Meanwhile, the industry costs European society approximately €446 million per year after accounting for its environmental and public health consequences.7 Consumers and fashion brands are also turning away from fur, and 24 (out of 27) EU Member States have already enacted production bans or restrictions on fur farming.7
The public moral concerns about the welfare of animals on fur farms, which precipitated these restrictions, are also well-founded. Indeed, the European Food Safety Authority concluded through an independent scientific investigation that, in the current caged fur farming system, the most serious adverse welfare consequences for mink, foxes, raccoon dogs and chinchillas cannot be prevented or substantially mitigated in the majority of cases.10 It is highly doubtful that changing cage dimensions, introducing enrichment requirements or inspection regimes will achieve meaningful animal welfare improvements. What it certainly will not do is remove the core epidemiological hazards posed by fur farming, namely keeping large numbers of captive bred-wild mammals in intensive systems where viruses can circulate and evolve.
If the European Commission intends to do more than merely pay lip service to One Health, it must accept accountability and take action before the next zoonotic crisis occurs. Banning fur farming would demonstrate what effective One Health policy looks like in practice: eliminating an avoidable anthropogenic source of zoonotic disease risk, while responding to citizens' concerns, thereby establishing Europe as a global leader in upstream pandemic prevention.

        (Continue. . . )


The concern, particularly with high density animal farms, is that it provides the virus with an ideal environment to spread from mammal to mammal. Long chains of infection (see graphic below) can provide the virus with additional opportunities to adapt to a new host species, furthering its evolution.

 Admittedly, the next pandemic could arise from any farmed livestock (poultry, swine, cattle, etc.), or even from the wild. We can never truly pandemic-proof our world. 

But fur farming practices are arguably more conducive to the generation and spread of zoonotic viruses, as mink are highly susceptible to influenza and coronaviruses, and it is common in many countries to feed raw poultry or poultry meat products to mink raised in captivity.

Whether we can summon the political will to do something about this threat remains to be seen.  

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Wednesday, September 09, 2026

NERC Reliability Report: Large Computational Load Risks Due to Voltage Sensitivity

 

Link

What is a catastrophic power outage?
• Events beyond modern experience that exhaust or exceed mutual aid capabilities
• Likely to be no-notice or limited-notice events that could be complicated by a cyber-physical attack
• Long duration, lasting several weeks to months due to physical infrastructure damage
• Affects a broad geographic area, covering multiple states or regions and affecting tens of millions of people
• Causes severe cascading impacts that force critical sectors—drinking water and wastewater systems, communications, transportation, healthcare, and financial services—to operate in a degraded state
 (Excerpt From Dec 2018 NIAC Report)

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Eight years ago, in NIAC: Surviving A Catastrophic Power Outage, we looked at a presidential commission's report on the risks of a major, prolonged, grid collapse.  

This 92-page report was released a little more than a year after hurricane ravaged Puerto Rico suffered the longest (11-month) grid failure in American History  and a year following another report - DHS: NIAC Cyber Threat Report - August 2017 - that warned of growing cyber threats to our critical infrastructure and called for `bold, decisive actions'.

While previously the biggest threats to the grid were thought to be natural disasters (earthquakes, hurricanes, ice storms, severe space weather, etc.), `bad actors' (cyber-threats, sabotage, etc.), or aging infrastructure (see ASCE report card on America’s infrastructure), the recent and rapidly increasing power demands from A.I. data centers and bitcoin mining operations have added yet another potential point of failure.

Last summer the U.S. Department of Energy published a 73-page report that warned that if current schedules for retirement of reliable power generation (especially baseload) continue, without enough firm replacement, the risk of blackouts by 2030 could increase dramatically.

Number one on their Key Takeaways was:
Status Quo is Unsustainable. The status quo of more generation retirements and less dependable replacement generation is neither consistent with winning the AI race and ensuring affordable energy for all Americans, nor with continued grid reliability (ensuring “resource adequacy”).
 
Absent intervention, it is impossible for the nation’s bulk power system to meet the AI growth requirements while maintaining a reliable power grid and keeping energy costs low for our citizens.
In 2006 NERC, or the North American Electric Reliability Corporation, was tasked with "ensuring the reliability of the North American bulk power system" following the 2003 Northeast blackout which affected more than 50 million people in the United States and Ontario, Canada.

We've been following their reliability reports and mitigation efforts for many years, but last February we looked at an a 181-page NERC Long-Term Reliability Report which warned that our power grid is facing a growing risk of electrical shortfalls over the next decade.

For those wanting a brief summary, NERC published the following press release (see Resource Adequacy Risks Intensify Across North America as Demand Growth Surges).

January 29, 2026

WASHINGTON, D.C. – NERC’s 2025 Long-Term Reliability Assessment (LTRA) and infographic spotlight intensifying resource adequacy risks throughout the North American bulk power system (BPS) over the next 10 years. Summer peak demand is forecast to grow by 224 GW, a more than 69% increase over the 2024 LTRA forecast with new data centers for artificial intelligence and the digital economy accounting for most of the projected increase.
Winter demand growth continues to outpace summer demand growth with 246 GW of growth forecast over the next 10 years, reflecting the evolution of electricity usage. Uncertainty and lag in the pace of new resource additions are driving heightened concerns that industry will not be able to keep up with rapidly increasing demand.

       (Continue . . . )

Four months ago, in NERC Issues Level 3 Alert As Grid Faces `Unprecedented Challenges' Due to Surge In Large Power Consumers we looked at a new threat; that the power draw from these massive computing centers can be erratic, with sudden drop offs and surges, that can destabilize the grid.

Previously, NERC had warned:
NERC, Regional Entities, and NERC registered entities have analyzed a series of disturbances that occurred on the bulk power system (BPS) resulting in widespread and unexpected customer-initiated load reduction of large loads. These disturbances involved multiple events during which 1,000+ MW of unexpected Large Loads output reduction occurred, with most events occurring in 2024 or 2025. The increase of Large Loads-related events coincides with an increase in Large Load penetration across the BPS.
Since then, it has become apparent that:
  • the risks are increasing
  • real-world events are already occurring,
  • and industry response to the earlier alert has been insufficient

While we've seen similar warnings for more than a year, this week NERC released a 3-page report which described several recent incidents where abrupt power demand drops temporarily affected the grid. 


(Excerpt)

One risk detailed by the LLWG and enumerated in two NERC incident reviews (1, 2) is the voltage sensitivity of computational loads. There have been several incidents involving computational loads that have been shown to impact BPS operations when the loads remove themselves from the system during system disturbances. Several voltage-sensitive customer-initiated load reductions have occurred in the Eastern Interconnection and the Electric Reliability Council of Texas (ERCOT) over the past two years.


The incidents largely unfold in a familiar pattern:

  • The grid experiences a normally cleared fault, and voltage dips occur as part of normal reclosing to isolate the fault.
  • After several reclosing attempts, computational load entities react to the voltage dips by transferring their load to their backup power systems, removing themselves from the grid, with the goal of protecting their equipment from outages and any potential damage resulting from prolonged voltage dips
  • As a result, large amounts of demand suddenly disappear from the BPS, creating oscillations on the systems as generation rebalances frequency and voltage to meet the remaining demand.

Historically, the electric grid has not experienced, nor planned or operated for, these significant amounts of simultaneous load losses in response to a fault on the system. Rather, planners and operators have traditionally focused on the risk of large generation losses (and generators must meet certain Reliability Standards associated with “riding through” these types of faults).

While these recent load reduction incidents did not create any near- or long-term issues for the system, future incidents could result in severe impacts given the expansion in the number and size of computational load sites, especially when their deployment is geographically concentrated (such as in “Data Center Alley” in Virginia).

 Additionally, since all computational loads on a circuit could see the same disturbance and take the same action, this creates significant common-mode failure risk.

       (Continue . . . )

While none of these reported incidents have seriously threatened the grid, and the tone of this report is cautiously optimistic that the risks going forward are manageable; it stresses that:

The North American BPS has reached a historic juncture defined by the rapid change in the nature and volume of electricity demand. Recent customer-initiated load reduction events underscore the potential significant risks that large computational loads may present to BPS reliability. Fortunately, mitigation options are available, and computational load stakeholders have taken proactive steps to work with NERC, the Regional Entities, and grid operators.  

While work is being done to reduce these risks, data centers aren't the only threat to the grid. As a Floridian who has gone through more than a few extended power outages - sometimes lasting a week or more - I've learned to put my faith more in preparedness rather than reassurances.   

Which is why I've got 60 gals of water stockpiled, a full pantry, and a basic solar power setup (see Emergency Solar Power: Revisited); enough to provide lights, fans, and to keep my phone charged. 

While I can't tell you what disruptions will come, or when they might occur, I firmly believe that being prepared - in advance - is the best insurance you and your family can have in an increasingly uncertain world.
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Tuesday, September 08, 2026

Poultry Sci & Mgt: Partial Protection of Commercial H5 Avian Influenza Vaccines to clade 2.3.4·4b H5N1 and H5N8 Avian Influenza Infections in Chickens


Poultry Vaccination - Photo Credit OIE

#19,327

Nearly 14 years ago, in Egypt: A Paltry Poultry Vaccine, we looked at an analysis by the researchers from the Virology department at St. Jude Children’s Research Hospital - that studied the effectiveness of six commercially available H5 poultry vaccines then deployed in Egypt.

They reported - out of the 6 vaccines tested - only one (based on a locally acquired H5N1 seed virus) actually appeared to offer genuine protection.

This was at a time when H5 vaccination was only utilized by a handful of countries (primarily China, Indonesia, Egypt, and Vietnam), and the OIE (now WOAH) routinely warned that vaccination of poultry `. . . cannot be considered a long-term solution to combating the avian flu virus'.

The authors of this study urged: 

In light of our findings, we recommend that the H5N1 prevention and control strategy in Egypt be updated and reinforced. Special consideration should be given to the vaccination strategy, and the use of vaccines based on currently circulating viruses is advisable.

Fast-forward 6 years (2018) and the St. Jude research team revisited Egypt's poultry vaccination program (see Sci. Reports: Efficacy Of AI Vaccines Against The H5N8 Virus in Egypt), and found many of the same problems persisted. 

They wrote:

Our results indicate that most of the commercial poultry H5 vaccines used in the present study were ineffective because the seed viruses in these vaccines are genetically distinct from the H5N8 viruses currently circulating in Egypt.

Although some of the commercial vaccines protected chickens from mortality, they failed to prevent chickens from shedding the virus. Accordingly, we recommend updating and reinforcing the H5N8 prevention and control strategies in Egypt. The vaccination strategy should be reconsidered based on currently circulating viruses.

While the reduced mortality among poultry may have seemed like a `win' for farmers, theses avian flu viruses could continue to spread - often unnoticed - due to the `masking' of symptoms by the vaccine.

Of course, Egypt wasn't alone in the continued use of older, mismatched, poultry vaccines.  Earlier in 2018, in PLoS One: Effectiveness of HPAI H5N1 Vaccination in Poultry - Indonesia, we looked at an assessment of that country's poultry vaccination campaign. 

HPAI vaccination, intensively applied in Sector 3 layers in Indonesia, had highly variable outcome, including vaccination failures and did not provide sufficiently long protective immunity in the majority of flocks. Indonesia adopted HPAI vaccination in 2004 with the aim of reducing the incidence of H5N1 infections in poultry, with the ultimate objective of achieving eradication of the virus.

The concern is that vaccine mismatches, and/or poor or inconsistent application, can allow avian flu to spread silently among flocks, and may allow AI viruses to continue to reassort and evolve, potentially leading to the emergence of new variants of avian flu.

 A few earlier blogs addressing those concerns include:

Subclinical Highly Pathogenic Avian Influenza Virus Infection among Vaccinated Chickens, China.

Study: Recombinant H5N2 Avian Influenza Virus Strains In Vaccinated Chickens

EID Journal: Subclinical HPAI In Vaccinated Poultry – China

While there have certainly been successful avian flu vaccination campaigns (see EID Journal: China's H5+H7 Poultry Vaccination Program, Guangdong 2017-18), vaccines must be continually updated - and flocks tested for breakthrough infections - in order to remain successful.  

In 2025, in NPJ Vaccines: Impact of Inactivated Vaccine on Transmission and Evolution of H9N2 Avian Influenza Virus in Chickens, we saw evidence that not only had inactivated vaccines failed to prevent - or even reduce - LPAI H9N2 in China's poultry, they may have driven viral evolution (including mammalian adaptations).

None of this is to suggest that an effective poultry vaccine campaign can't be mounted, or effectively maintained.  But it does require more than just a `vaccinate & forget' strategy. 

All of which brings us to a new study which finds that despite the introduction of newer vaccine formulations, many of the earlier concerns about Egypt's vaccination program persist.  I've only posted the Abstract, and some excerpts, so follow the link to read it in its entirety. 

I'll have a bit more after the break. 

Partial protection of commercial H5 avian influenza vaccines to clade 2.3.4·4b H5N1 and H5N8 avian influenza infections in chickens

Research
Open access
Published: 08 September 2026
Volume 3, article number 22 (2026)

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Ahmed El Taweel, Mokhtar Gomaa, Yassmin Moatasim, Omnia Kutkat, Mina Nabil Kamel, Mohamed El Sayes, Mohamed GabAllah, Mohamed Ahmed Ali, Ghazi Kayali & Rabeh El-Shesheny

Abstract

Background

Avian influenza viruses (AIVs) continue to cause substantial economic losses to the poultry industry and pose a significant burden on global public health systems. The increasing diversity and geographical spread of different subtypes of influenza viruses in poultry populations increases the risk for reassortment events and the emergence of novel strains. Vaccination remains a key strategy for preventing influenza infection and its complications, especially high pathogenic avian influenza (HPAI), as it can reduce morbidity, mortality, and viral transmission.

However, vaccine effectiveness is closely tied to the antigenic match between vaccine strains and circulating viruses. In this study, we tested six commonly used commercial poultry H5 vaccines in Egypt to evaluate mortality, and virus shedding following experimental infection of specific pathogen free chickens with clade 2.3.4·4b H5N1 and H5N8 HPAI viruses.

Results

Our results showed that most of the tested vaccines provided detectable antibody titers and protected against mortality but were not able to control virus shedding. ValleyVac vaccines induced high HI titers (up to 9 log2) against recent clade 2.3.4·4b A(H5N1) and A(H5N8) strains, while Zoetis and Egy-flu R 2-in-1 induced lower HI titers (<6 log2). Although some of the commercial vaccines did not elicit considerable HI titers, vaccines provided 71%–100% protection against clade 2.3.4·4b viruses. Importantly, virus titers were detected till seven days post-infection (dpi). This incomplete protection is likely due to genetic and antigenic mismatches between the vaccine seed strains and the H5N1 and H5N8 viruses detected in Egypt.

Conclusions

These results highlight the urgent need to revise H5Nx prevention and control strategies in Egypt and update vaccine seed strains to reflect currently circulating HPAI viruses.

(SNIP)

The prolonged use of suboptimal vaccines or inadequate vaccination programs may contribute to the selection of antigenic escape mutants through immune pressure, potentially reducing vaccine effectiveness.

        (SNIP)

In summary, our data indicate that vaccines designed on strains that differ from circulating strains are not able to provide optimal protection. Although an immune response was elicited and survival rates were high, viral shedding continued. This indicates that the use of those vaccines will reduce morbidity and mortality but will allow virus transmission and potentially the emergence of vaccine escape mutants.

Mass vaccination remains a crucial component of a multifaceted approach aimed at preventing AIV illness and its spread in poultry. The ongoing threat of an AIV pandemic highlights the need to design novel vaccines that are easier to manufacture, more streamlined, and capable of inducing better and broader immune protection against emerging strains.
 
        (Continue . . . )

 
These, and other (often trade related) concerns - are why many countries (including the United States, Canada and the UK) have yet to authorize the use of HPAI poultry vaccines, although many are studying the matter (see UK Defra Announces New Avian Influenza Vaccine Trials Begin in UK).

But as HPAI increases its presence in the environment -  and continues to spill over into livestock - the need for well mounted vaccination campaigns only increases. 

We've discussed some of the ongoing biosecurity measures that would be required to mount a safe and effective poultry vaccination campaign (see UK Joint Taskforce Policy Paper: Vaccination of Birds Against HPAIV (bird flu)), including:

  • Most captive birds would likely require more than one vaccination over their lifetime, and regular testing that can differentiate infected from vaccinated animals (DIVA) would be needed to prevent `subclinical spread' of the virus. 
  •  Culling and/or quarantine would still be needed for `breakthrough' infections
  • A different vaccine, schedule and testing regimen would likely be required for non-avian livestock.
  • And vaccine seed viruses would have to be regularly updated to match circulating strains
None of this would be cheap or easy, but - given the growing endemicity of the H5Nx virus - vaccination may be our best option going forward.

But only if we take the time and effort to do it right. 
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Monday, September 07, 2026

Pathogen's Progress

H5 Affected States & Provinces June 2015


#19,326

Prior to 2021, North America had only had one brush with the Asian-origin HPAI H5 virus; a reassorted H5N8 subtype which appeared in South Korea in January of 2014 before beginning a world tour. 

It crossed the north Pacific - carried by migratory birds - the following fall, arriving in the Pacific Northwest in December 2014, sparking the first HPAI H5 epizootic in the United States and Canada (see map above).

That H5Nx virus, however, disappeared completely the following summer, apparently still ill-suited for long-term carriage by wild and migratory birds (see PNAS: The Enigma Of Disappearing HPAI H5 In North American Migratory Waterfowl).

That limitation would evaporate in the summer of 2016 when H5N8 reassorted into a far more robust threat (probably in China or Siberia) - arriving in Europe in October - and sparking their biggest (at that time) epizootic on record. EID Journal: Reassorted HPAI H5N8 Clade 2.3.4.4. - Germany 2016). 

This new H5N8 was not only deadlier to some bird species, it was more easily carried by others, increasing its range and impact dramatically over the next 6 months.  
We also saw this virus spin off several short-lived subtypes, including H5N5, H5N3, and H5N9. 
Over the winter of 2016-17, this H5N8 virus spread from Europe, into the Middle East, and then North Africa. By late spring, 2017, it had crossed the equator for the first time,  and set up shop in South Africa, making it the most successfully disseminated HPAI H5 virus we'd seen.
A European H5N6 briefly appeared in 2018, but H5N8 held on until a new, reassorted H5N1 virus appeared in Europe in 2020, and began to supplant H5N8. 

Unlike previous H5Nx incarnations, this new H5N1 showed an increased affinity for infecting mammals, and a much wider avian host range (see DEFRA: The Unprecedented `Order Shift' In Wild Bird H5N1 Positives In Europe & The UK).

By 2022 this `new and improved' H5N1 virus had crossed both the Atlantic and Pacific oceans, spreading first to North America, followed by South America, the Antarctic, and most recently (2026) into Australia/New Zealand.   

While avian flu activity still decreased during the hotter months, no longer did HPAI H5 disappear completely each summer. It could be maintained (at low levels) in local birds, livestock, small mammals, and likely even the environment. 

All of which makes the HPAI H5 threat of today far different from what it was even a decade ago. The H5N1 virus of today has expanded not only its geographic range, but its host range as well.  

And it isn't done evolving. 

Since its arrival in 2021, the H5Nx virus has diversified into more than 100 distinct genotypes in North America alone, with scores of others emerging around the globe.  A few notable North American examples include:

These variants illustrate just how quickly (and dramatically) the avian `fluscape' can change, and we generally see those changes in the fall, when migratory birds - which spent their summers in their high latitude roosting areas - return. 

A 2016 study (see Sci Repts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission Of HPAI H5N1), suggests that waterfowl pick up new HPAI viruses in the spring (likely from poultry or terrestrial birds) on their northbound trip to their summer breeding spots - where they spread and potentially evolve - and then redistribute them on their southbound journey the following fall.

Our own Arctic Refuge, where more than 200 bird species spend their summers, serves as a central hub, and funnels migratory birds south via all four North American Flyways.

While this fall's HPAI viruses could be similar to what we saw last year - they might include new, potentially game-changing, genotypes - which could either increase or decrease their threat.

Evolution is a double-edged sword, and what it adds it can also take away. But the trajectory of H5N1 over the past 4+ years has been towards more mammalian adaptation, and increased host range.  

The APPA estimates `Eleven (11) million U.S. households own backyard chickens (a 28% increase from 2023)', yet a recent survey (see MMWR: Knowledge, Attitudes, and Practices Regarding Avian Influenza Among Owners of Backyard Flocks) found significant gaps in their knowledge of dealing with avian flu.

While no one can predict with any confidence what HPAI will look like later this fall, the one thing we can be sure of is the 2026 fall southbound migration has already begun, and the time to prepare for its arrival grows shorter with every passing day. 

And if recent history is any guide, we should be preparing for additional surprises. 

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Sunday, September 06, 2026

CDC Update: Flu Levels Remain Low, But COVID Increasing Across the U.S.

 
          Last Week                               This Week

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Last week, after a summer of low COVID activity reported in the United States, we looked at Low But Increasing COVID reports across the nation.  At that time, wastewater testing in 8 states indicated increased activity, while this week (see graphic above) the number of states has risen to 11. 

At the same time, the percentage of positive tests for COVID has jumped from 5.3 last week to 6.2 this week. Still low, but edging higher. 


The CDC's weekly summary reads:


Testing, and reporting, of COVID cases remain low, and so the CDC's Nowcast is unable provide us with much in the way of details on this summer's variants.


Last month the FDA approved a new JN.1 lineage XFG subvariant COVID vaccine (see CIDRAP FDA approves new COVID vaccines) which should be available later this fall.

Currently, influenza and RSV are reportedly at very low levels (see chart below), but with fall approaching, those numbers are expected to rise in the months ahead. 


As reported a little over a week ago (see Japan MHLW Reports Unusually Early Start to the Fall Flu Season) a few countries in the Northern Hemisphere are already reporting substantial flu, even as the virus continues in the Southern Hemisphere. 

Admittedly, every flu season is different, and it is not unusual to see vastly different flu seasons in different parts of the world. So flu's early arrival in Japan may not be a harbinger for North America or Europe.

This year's fall flu vaccines have been updated to reflect recent antigenic changes observed in all 3 seasonal flu types (see WHO Recommendations for Influenza Vaccine Composition for the 2026-2027 Northern Hemisphere Influenza Season).

While no flu vaccine can promise 100% protection, it – along with practicing good flu hygiene (washing hands, wearing face masks in crowded indoor spaces, covering coughs, & staying home if sick) – remains your best strategy for avoiding the flu and staying healthy this winter.

For some more reasons to consider getting the flu vaccine, you may wish to revisit:

Eurosurveillance: Influenza Vaccination Attenuates Acute Myocardial Infarction and Stroke Risk Following Influenza Infection

Nature: Influenza Vaccination & Major Cardiovascular Risk: a Systematic Review & Meta-Analysis

The Lancet: Influenza Vaccine to Reduce Adverse Vascular Events in Patients with Heart Failure

AHA: Study Shows Flu Shots Reduce Deaths From Heart Failure

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