J.I.D.: Development & Characterization of Candidate Vaccine Viruses against HPAI A(H5) Viruses for Rapid Pandemic Response

 
WHO H5 CVV list (n=46)

#19,072

Two days ago, in WHO: Candidate Vaccine Viruses for Pandemic Preparedness - Feb 2026, we looked at the latest WHO recommendations for CVVs (Candidate Vaccine Viruses) against zoonotic influenza viruses.

While no new H5 CVVs were recommended,  antigenic characterization of several recent isolates were pending, and H5 continues to evolve. 

Less well known is that the CDC also maintains their own list of  HPAI H5 CVVs - and while there are some overlaps with the WHO's list - there are some differences (see How The WHO & CDC Are Developing Candidate H5N1 Vaccines).   

On the same day that the WHO released their semi-annual zoonotic vaccine update recommendations, the Journal of Infectious Diseases published the following CDC review of 25 existing H5 CVVs, and how well they might work against current (U.S & Cambodian) H5N1 strains. 

CVVs are `seed viruses' which have been antigenically matched to various legacy strains of H5 - and were determined to grow reasonably well in an egg medium - which means they could be quickly used to begin vaccine manufacturing. 

The big caveat is that antigenic matching is done using HI assays in ferrets, which may not fully predict its effectiveness in humans. And - as this report cautions - even tiny changes in the virus can have major impact on its antigenic profile. 

In one of their studies, researchers looked at two clade 2.3.2.1e viruses collected from humans in Cambodia in 2023. The two isolates were:

• A/Cambodia/NPH230032/2023
• A/Cambodia/NPH230776/2023

Despite their genetic similarity, they reacted quite differently.  

• Encouragingly, the A/Cambodia/NPH230032/2023 virus showed broad cross-reactivity against several legacy CVVs. 

• A/Cambodia/NPH230776/2023, however, showed reduced cross-reactivity against many of those same CVVs, with only a specific 2.3.2.1 lineage CVV showing strong inhibition.

While it is possible that an interim vaccine might be developed early in the next pandemic based on an existing CVV - potentially shaving weeks or even months off the manufacturing process - a lot of things would have to go `right'. 

But since a targeted strain-specific vaccine could take 6 months or more to develop, having an existing library of CVVs to draw from might  save a lot of lives. 

I've only posted the abstract, and a few excerpts from the results and discussion. Follow the link to read it in its entirety. 

Development and Characterization of Candidate Vaccine Viruses against High Pathogenicity Avian Influenza A(H5) Viruses for Rapid Pandemic Response  

Li Wang , Jieru Wang , Jaber Hossain , Hans C Cooper , Cindy Adolphus , Michael Currier , Ginger Atteberry , Chenchen Feng , Marie K Kirby , Han Di ... Show more

The Journal of Infectious Diseases, jiag132, https://doi.org/10.1093/infdis/jiag132
Published: 28 February 2026

PDF

Abstract

High pathogenicity avian influenza A(H5) viruses pose a pandemic threat. These viruses have rapidly evolved in birds and frequently crossed species barriers, resulting in over 1,000 confirmed human infections, with a case fatality proportion of approximately 50%. In response, the U.S. CDC has developed dozens of A(H5) candidate vaccine viruses (CVVs) over the past two decades, primarily targeting clades known to infect humans. This report summarizes the development and characterization of the CVVs, with a particular focus on their antigenic relationships with clades 2.3.2.1e and 2.3.4.4b A(H5N1) viruses, which have been responsible for the majority of recent human infections.

 

(SNIP)

Given the ongoing A(H5N1) outbreaks in birds and mammals, along with zoonotic transmission to humans caused by clades 2.3.4.4b and 2.3.2.1e, we aimed to evaluate the ability of antibodies raised against these CVVs in ferrets to inhibit hemagglutination of representative strains from these two clades. 

Three recent human A(H5) isolates were tested in the HI assay: A/Texas/37/2024(TX37), a clade 2.3.4.4b virus representing the first human case of the 2024 U.S. dairy cattle A(H5)outbreak; A/Cambodia/NPH230776/2023 and A/Cambodia/NPH230032/2023, both clade2.3.2.1e viruses isolated in 2023.

Seven out of 16 heterologous ferret antisera inhibited the TX37 virus with HI titers within a 2-fold difference compared to the homologous HI titer (Table 2). Out of those seven antisera, four were raised against CVVs belonging to genetic clades different from TX37.

Similarly, eight ferret antisera raised against these A(H5) CVVs inhibited A/Cambodia/NPH230032/2023 (2.3.2.1e) despite seven of the CVVs being from heterologous genetic clades. Interestingly, only two ferret antisera inhibited A/Cambodia/NPH230776/2023, though it belongs to clade 2.3.2.1e, the same clade as A/Cambodia/NPH230032/2023 (Table 2).

Twelve amino acid differences within HA1, including substitutions in the receptor-binding domain and antigenic site B, are likely responsible for the observed difference in cross-reactivity of CVV antisera against these two viruses (Supplementary Table 3).

DISCUSSION

In this study, we provided a comprehensive overview of 25 A(H5) CVVs developed at the CDC over the past two decades, including detailed information on their HA titers, EID₅₀ values, and viral protein yields. These CVVs have been distributed to government agencies, vaccine manufacturers, academic institutions, and other stakeholders to facilitate laboratory characterization, regulatory evaluation, and vaccine manufacturing. 

 (SNIP)

While ferret antisera provide a valuable surrogate model for antigenic characterization, it is important to acknowledge their limitations. Species-specific differences in immune responses between ferrets and humans are well-documented for seasonal influenza viruses [13]. Human serological data for clades 2.3.2.1e and 2.3.4.4b viruses remain limited, although a recent study has begun to address this gap [14]. Future efforts should prioritize evaluating antibody responses in individuals vaccinated with A(H5) vaccines or previously infected with A(H5) viruses to better assess the potential for cross-protection against emerging zoonotic strains.

In conclusion, maintaining a diverse and regularly updated A(H5) CVV library is critical for global readiness as avian influenza viruses continue to evolve. The demonstrated cross-reactivity of several heterologous CVVs with current zoonotic strains underscores the importance of antigenic breadth in CVV selection and suggests that some stockpiled or previously developed candidates may provide adequate protection and enable rapid vaccine production, offering valuable lead time during outbreak response.

(Continue . . .)

 

Nature Comms: The Risk of Kidney Disease Increases Following SARS-CoV-2 Infection Compared to influenza

 

Nature Med. Review: Extrapulmonary manifestations of COVID-19

#19,071

Now that 90% of the world's nations are no longer reporting COVID infections, hospitalizations, and deaths (see No News Is . . . Now Commonplace), the current health burden of COVID infection is largely obscured.  

Estimates put the number of U.S. daily infections at > 90K (see Estimated Burden of COVID-19 Illnesses, Medical Visits, Hospitalizations, and Deaths in the US From October 2022 to September 2024), but with limited testing, no one really knows.  

Even though COVID has lost much of its initial lethality, the above study suggests it caused 1.1 million hospitalizations, and 101 300 deaths in the U.S. during the study period.

Also not reliably counted are the long-term impacts of (often repeated) COVID infection.  `Long-COVID' - or Post COVID Syndrome - has been estimated to affect up to 20% of survivors. 

Research also suggests that with each SARS-CoV-2 reinfection, the risks of complications or developing Long COVID increase. With fewer people getting vaccinated/boosted, and fewer still bothering with NPIs, multiple reinfection's are increasingly commonplace. 

While world governments (and the general public) seemingly don't want to hear about it, the evidence of long-term harm from repeated (even mild) COVID infection continues to mount.  

A few (of many) recent studies include:

EID Journal: Thrombotic Events and Stroke in the Year After COVID-19 or Other Acute Respiratory Infection

Referral: JAMA - COVID-19 in Pregnancy Linked With Risk of Neurodevelopmental Disorders in Early Childhood

European Society of Cardiology: Major Consensus Statement Released on Long-Term Cardiovascular Impact of COVID Infection

EHJ: Accelerated Vascular Ageing After COVID-19 Infection: The CARTESIAN Study

BMC Neurology: Long-term Neurological and Cognitive Impact of COVID-19: A Systematic Review and Meta-analysis in over 4 Million Patients

To this growing preponderance of evidence we can add a new study, just published in Nature Comms, which finds increases in both acute kidney injury (AKI) and chronic kidney disease (CKD) following COVID infection. 

Those with long memories will recall that we first saw evidence of COVID infection's impact on the kidneys more than 5 years ago (see JASN: Acute Kidney Injury In Hospitalized Patients With COVID-19).

This wasn't entirely surprising, since the SARS-CoV-2 virus enter cells via ACE2 receptors, which are particularly abundant in numerous renal tubules in human kidneys. Many early studies reported a high rate of AKI and CKD following COVID hospitalization. 

Since the full edited version of this study hasn't been posted, I'll simply post the following abstract and summary.  Follow the link to read it in its entirety. 

I'll have a bit more after the break.

The risk of kidney disease increases following SARS-CoV-2 infection compared to influenza

Yue Zhang,  Nasrollah Ghahramani, Vernon M. Chinchilli & Djibril M. Ba

Communications Medicine , Article number: (2026) Cite this article

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Abstract

Background

Although case reports and observational studies suggest COVID-19 increases the risk of kidney diseases, real-world evidence comparing it with influenza is limited. Our study aims to assess the association between COVID-19 infections and subsequent kidney diseases, using influenza as a positive control and incorporating a negative control to establish clearer associations.

Methods

A large retrospective cohort study with strata matching was conducted using the MarketScan database with records from Jan. 2020 to Dec. 2021. We used the ICD-10 codes to identify individuals and build three cohorts: (1) COVID-19 group, (2) Positive control group: Influenza but no COVID-19, and (3) Negative control group: no COVID-19 / Influenza. The outcomes were acute kidney injury (AKI), chronic kidney disease (CKD), end-stage renal disease (ESRD), and glomerular diseases. Multivariable stratified Cox proportional hazards regression analyses were performed.

Results

The study includes 939,241 individuals with COVID-19, 1,878,482 individuals in the negative control group, and 199,071 individuals with influenza. COVID-19 is significantly associated with increased risks of AKI (adjusted hazards ratio, aHR: 2.74; 95% CI, 2.61-2.87), CKD (aHR: 1.38, 1.32-1.45), ESRD (aHR: 3.22, 2.67-3.88), and glomerular diseases (aHR:1.28, 1.09-1.50), while influenza has no impact on CKD, ESRD, and glomerular diseases. Time-specific analyses indicate that COVID-19 has stronger effects on AKI in the short term but has stable long-term effects on CKD.
Conclusions

In this large real-world study of working-age, commercially insured adults in the United States, COVID-19 infection is associated with a 2.3-fold risk of developing AKI, a 1.4-fold risk of CKD, and a 4.7-fold risk of ESRD compared to influenza. Greater attention to kidney diseases post-COVID-19 is essential to prevent future adverse health outcomes.

Plain Language Summary

COVID-19, caused by the SARS-CoV-2 virus, has been linked to multiple organ complications, with emerging evidence suggesting effects on kidney diseases. However, it is unclear how the risk of kidney disease after COVID-19 compares with influenza, another common viral infection. In this study, we analyzed commercial health insurance data from over three million working-age adults in the United States to compare individuals with COVID-19, those with influenza, and those with neither infection. We found that individuals who had COVID-19 were more likely to develop kidney problems, including short-term injury and long-term chronic disease. These findings suggest that COVID-19 may have a stronger impact on kidney diseases than influenza, highlighting the need for greater attention and monitoring of kidney function after COVID-19 infection.

For a variety of economic, societal, practical, and political reasons the world decided more than 3 years ago that COVID should be treated as a `mild, almost trivial flu-like' illness. 

And while it is true that > 99 out of every 100 COVID cases survives, disability claims have skyrocketed (see CSIRO Pub: Impacts of Long COVID on Disability, Function and Quality of Life for Adults Living in Australia), and chronic illnesses are increasing.

Based on limited data, the WHO estimates that 1 in 6 people who contract COVID will develop some degree of `Long COVID'. Globally, that suggests > 400 million people, and > 20 million in the United States.

Which is one of the reasons why, as recently as late December, we saw a WHO Statement: COVID-19 Still Causes Severe Disease & Renewed Vaccination Recommendations.

 But it is unclear, at this late stage, whether anyone is still listening. 

WHO: Candidate Vaccine Viruses for Pandemic Preparedness - Feb 2026

Credit NIAID

#19,070

In addition to deciding which influenza viruses to include in the next seasonal flu vaccine (see WHO Recommendations for Influenza Vaccine Composition for the 2026-2027 Northern Hemisphere Influenza Season), twice each year flu researchers are asked by WHO to advise on the development of new CVVs (Candidate Vaccine Viruses) for zoonotic influenza.

While our attentions are primarily focused on the clade 2.3.4.4b H5N1 virus, there are literally dozens of other zoonotic influenza A viruses circulating around the world (see CDC IRAT list), all of which are believed to have some degree of pandemic potential.

Each year new variants - subclades, subtypes, or genotypes - emerge, and the WHO must decide if they warrant the creation of a CVV. Since H5 viruses evolve rapidly, many older CVVs no longer match circulating strains.

Having a proven CVV already tested and approved can save valuable time if  rapid production and distribution of a pandemic vaccine are ever required.

And over the past two decades, the WHO has recommended a lot of them (see list below). Forty-six are approved and available, and 6 are pending. And that's just for H5 subtypes.

They WHO has also approved 22 H7 CVVs (20 available, 2 pending), and 11 H9 CVVs (8 available, 3 pending), along with a smattering of other subtypes (H1, H3, H10, etc.).

This week the WHO published a 13-page update which contains background information on a wide range of novel avian and swine flu viruses detected over the past 6 months.  

While they cite ongoing antigenic changes - particularly among the H5Nx panoply of viruses - in the end only one new CVV was recommended for development; a new A/Hunan/40087/2025-like H9N2 CVV.

We've been following concerning antigenic changes in H9N2 viruses for quite some time (see China CDC Weekly: Epidemiological and Genetic Characterization of Three H9N2 Viruses Causing Human Infections — Changsha City, Hunan Province, China, April 2025).

While no new H5 CVVs were recommended, antigenic characterization is still pending on a number of recent human H5 infections, including last September's H5N2 case from Mexico, and several recent  H5N1 cases in Cambodia (clade 2.3.2.1e), along with a number of poultry isolates collected from Egypt, Laos, and Brazil. 

This report also finds that the recent H5N5 virus isolated from a human in Washington State showed reduced reactivity to existing CVVs.

The HA1 of the A(H5N5) virus from the human case in the United States of America had five amino acid substitutions relative to the A/Astrakhan/3212/2020 CVV, including a gain of a potential glycosylation site. Post-infection ferret antisera raised against clade 2.3.4.4b A/American Wigeon/South Carolina/22-000345-001/2021, A/Ezo red fox/Hokkaido/1/2022 and A/Astrakhan/3212/2020 CVVs showed reduced reactivity to the A(H5N5) virus.

For now, however, the WHO has decided the threshold has not been met to justify recommending the creation of an H5N5 CVV.  

I've only posted the summary, follow the link to read it in its entirety. I'll have a bit more after the break. 

Genetic and antigenic characteristics of zoonotic influenza A viruses and development of candidate vaccine viruses for pandemic preparedness

February 2026

The development of influenza candidate vaccine viruses (CVVs), coordinated by the World Health Organization(WHO), remains an essential component of the overall global strategy for influenza pandemic preparedness.

Selection and development of CVVs are the first steps towards timely vaccine production and do not imply a recommendation for initiating manufacture. National authorities may consider the use of one or more of these CVVs for pilot lot vaccine production, clinical trials and other pandemic preparedness purposes based on their assessment of public health risk and need.

Zoonotic influenza viruses continue to be identified and evolve both antigenically and genetically, leading to the need for additional CVVs for pandemic preparedness purposes. Changes in the antigenic and genetic characteristics of these viruses relative to existing CVVs and their potential risks to public health justify the need to develop new CVVs.

This document summarizes the antigenic and genetic characteristics of recent zoonotic influenza viruses and related viruses circulating in animals1 that are relevant to CVV updates. Institutions interested in receiving these CVVs should contact WHO at gisrs@who.int or the institutions listed in announcements published on the WHOwebsite2.

       (Continue . . . )

While having a closely-matched CVV might shave weeks or even months off the time it would take to develop, manufacture, and deploy a pandemic vaccine, there are still many obstacles to overcome.  

Any flu jab would likely require 2 shots - 30 days apart - and even under the best case scenarios, it would likely take 6 months or longer before substantial quantities of vaccine are available to the public. 

Some past blogs on some of the logistics of developing a pandemic vaccine include:

Referral: SCI AM - A Bird Flu Vaccine Might Come Too Late to Save Us from H5N1

NPJ Vaccines: Modeling the Impact of Early Vaccination in an Influenza Pandemic in the United States

How The WHO & CDC Are Developing Candidate H5N1 Vaccines

Manufacturing Pandemic Flu Vaccines: Easier Said Than Done

FluView Week 7: Influenza Remains Elevated & Additional Reports of Antiviral Resistance

 

https://www.cdc.gov/fluview/surveillance/2026-week-07.html

#19,069

Three months into this year's influenza season and flu activity remains elevated across much of the country (see map above), although we are seeing a decided shift from influenza A (primarily H3N2) to influenza B (see chart below).

While the big story of this year's flu season has been the emergence of a `drifted' H3N2 subclade K virus, another aspect we've been following have been sporadic reports around the world of reduced oseltamivir effectiveness against H1N1 due to NA-I223V and NA-S247N amino acid substitutions.

A few blogs include:

Eurosurveillance: Expansion of influenza A(H1N1)pdm09 NA:S247N Viruses with Reduced Susceptibility to Oseltamivir, Catalonia, Spain, and in Europe, July to October 2025

China: National Influenza Center Reporting Increased Oseltamivir Resistance in Seasonal H1N1

Taiwan CDC Statement On Increased Antiviral Resistance in Seasonal H1N1 Cases in 2025

Since 2009, global resistance to oseltamivir has run < 1%, although we've seen sporadic community clusters of H275Y mutations (see here, here, and here) and low‑levels of  I223V/S247N reported (see here and here). 

Over the entire 2024-2025 flu season - out of 1697 H1N1 viruses tested - only one carried the NA-I223V and NA-S247N amino acid substitutions.

Reassuringly, during the first 13 weeks of the 2025-2026 flu season (Oct - Dec) the CDC reported zero elevated resistance among the first 193 H1N1 viruses tested (see screenshot from FluView Wk 53).  

On January 10th (Fluview Wk 1), however, the CDC reported 2 (out of now 224) H1N1 viruses (0.2%) tested showed `reduced inhibition by oseltamivir' due to amino acid substitutions NA-I223V and NA-S247N. 

Two weeks ago, in FluView Week 5: Influenza Remains Elevated & Slight Uptick In Antiviral Resistance, we saw that count had increased to 7 reduced inhibition and 3 highly resistant (due to the more worrisome H275Y mutation).

Yesterday's FluView (week 7) - based now on 517 H1N1 isolates tested since October - reports 3 more reduced inhibition (n=10) and a 4th with highly reduced inhibition.

Four A(H1N1)pdm09 viruses had NA-H275Y amino acid substitution conferring highly reduced inhibition by oseltamivir and peramivir. Ten A(H1N1)pdm09 viruses had amino acid substitutions NA-I223V and NA-S247N and showed reduced inhibition by oseltamivir. Two B viruses had amino acid substitution NA- M464T and showed reduced inhibition by peramivir.

The impact of the H275Y mutation on oseltamivir resistance is far greater than I223V/S247N, but the stacking of H275Y with either I223V or S247N can greatly enhance the effect.

Although elevated above the historic baseline, these latest numbers still remain fairly low, and should not affect clinical decisions regarding antiviral treatment. 

But as a trend, they are very much worth noting.  

Which is why we'll be watching future reports to see if these numbers plateau, or continue to rise.  

WHO Recommendations for Influenza Vaccine Composition for the 2026-2027 Northern Hemisphere Influenza Season

Credit ACIP
 

#19,068

Twice each year international influenza experts meet to discuss recent developments in human and animal influenza viruses around the world, and to decide on the composition of the next influenza season’s flu vaccine.

Due to the time it takes to manufacture and distribute a vaccine, decisions on which strains to include must be made at least six months in advance. 

As occasionally happens, that can provide a window of opportunity for `drifted' or mutated flu strains to emerge, and spread globally (see last Nov's Increasing Concerns Over A `Drifted' H3N2 Virus This Flu Season).

Earlier this week, in Preprint: Near Real-time Data on the Human Neutralizing Antibody Landscape to Influenza Virus as of Early 2026 to Inform Vaccine-strain Selection, we looked at a `near real-time' assessment of the human neutralizing antibody landscape against currently circulating influenza A viruses.

A review which found that most people have low antibody defenses against recently emerged H3N2 subclade K and H1N1 D.3.1.1 viruses.

Today the WHO released their recommendations for the composition of this fall's 2026-2027 Northern Hemisphere flu vaccine, which recommends updates for all 3 flu strains; H1N1, H3N2, and Influenza B.

Overview

For vaccines for use in the 2026-2027 northern hemisphere influenza season, WHO recommends the following:

Egg-based vaccines

• an A/Missouri/11/2025 (H1N1)pdm09-like virus;

• an A/Darwin/1454/2025 (H3N2)-like virus; and

• a B/Tokyo/EIS13-175/2025 (B/Victoria lineage)-like virus.


Cell culture-, recombinant protein- or nucleic acid-based vaccines

• an A/Missouri/11/2025 (H1N1)pdm09-like virus;

• an A/Darwin/1415/2025 (H3N2)-like virus; and

• a B/Pennsylvania/14/2025 (B/Victoria lineage)-like virus.

The 2026 Southern Hemisphere vaccine already has the recommended updated H1N1 component, but retains older strains against H3N2 and Influenza B. Despite this apparent mismatch, it will still likely provide important protection against severe disease.

Sadly, seasonal flu vaccine uptake in the United States peaked in 2019, and has begun a slow, but steady decline since.

Pandemic fatigue, plus growing anti-vaccination sentiment, and admittedly `hit-or-miss' protection against influenza infection have all had an impact.  

But the more we learn about influenzas' extrapulmonary impacts on the body (see Risk of Cardiovascular Events After Influenza: A Population-based Self Controlled Case Series Study), the more important protecting yourself becomes.

Which is why I consider the flu vaccine to be an important part of my `flu prevention' strategy each year (along with masking, handwashing, and avoiding indoor crowds).    

While none of this guarantees I'll continue to go unscathed, my last bout with `flu' was in the summer of 2009 (after attending a pandemic flu conference!), and I've only contracted COVID once, before the first vaccine was released.

Since my strategy seems to work, I see no reason to `fix' it. 

South Korea: MAFRA Extends Special Quarantine Period for 3rd Month (to March 31st)

 

#19,067

On January 5th, South Korea ordered Special Quarantine Measures Implemented for one Month to Prevent the Spread of HPAI, which was extended in early February due to concurrent outbreaks of FMD and ASF along with ongoing HPAI.

Over the past 3 weeks the number of ASF outbreaks has more than tripled (from 6 to 20), and more than a dozen HPAI outbreaks have been reported in poultry.  

As noted on Wednesday, a new subtype (H5N9) has been increasingly reported in South Korea, and MAFRA has already ordered their third 24-hour halt in the transport of livestock (poultry, ducks, and pigs) this week.

Today, MAFRA published an extraordinary (14.5 mb) collection of 132 maps and aerial photos (see sample below), of migratory bird arrival areas where livestock-related vehicles and workers are restricted from entering.

Given that the northbound phase of Korea's migratory bird season begins in early March - and often extends into May - this may not be the last extension to this special quarantine period we see. 

Some (translated) excerpts from today's announcement follow:

The special quarantine period for livestock infectious diseases has been extended until March, and all-out measures are being taken to prevent further outbreaks.

February 27, 2026, 3:44 PM, Quarantine Policy Bureau 

The Central Disaster and Safety Countermeasures Headquarters ( Director Song Mei-ryeong, Minister of Agriculture, Food and Rural Affairs , hereinafter referred to as the Central Disaster and Safety Countermeasures Headquarters ) for Livestock Infectious Diseases ( Highly Pathogenic Avian Influenza , Foot - and-Mouth Disease, African Swine Fever ) announced that considering the current risk of additional outbreaks of livestock infectious diseases, the existing special quarantine period (October 1, 2025 - February 28, 2026) will be extended by one month until March 31 ( Friday ) to strengthen quarantine management .

1. Highly pathogenic avian influenza (AI)

< Occurrence situation and situation diagnosis >

This winter ('25/'26 season ) , there have been 50 cases of highly pathogenic avian influenza in poultry farms and 59 cases in wild birds .

* Poultry farm occurrence status ( total 50 cases ): 11 cases in Gyeonggi , 9 in North Chungcheong , 9 in South Chungcheong , 4 in North Jeolla , 10 in South Jeolla , 4 in North Gyeongsang , 1 in South Gyeongsang , 1 in Gwangju , 1 in Sejong

** Status of wild bird detection ( total 59 cases ): Gyeonggi 6 , Gangwon 6, Chungbuk 1, Chungnam 14, Jeollabuk-do 6, Jeollanam-do 7 , Gyeongbuk 3, Gyeongnam 5, Jeju 4, Seoul 3, Busan 2, Incheon 1, Gwangju 1

In our country, highly pathogenic avian influenza first occurred in a poultry farm (September 12, 2025) 47 days earlier than the previous 24/25 season (October 29, 2024) during this 25/26 winter season . The outbreak area has also expanded significantly ( from 26 cities and counties to 29 ) compared to last season . In addition , the number of detections in wild birds has increased from 43 to 59 , and the detection area has expanded nationwide (from 30 cities and counties to 38 ) . Therefore, it is necessary to strengthen quarantine management, such as thorough disinfection and access control, more than ever before .

The Central Disaster and Safety Countermeasure Headquarters assessed that there is a risk of additional outbreaks considering that the results of the February migratory bird population survey showed that there were 1.33 million birds * , a large number of birds inhabiting the area , and that highly pathogenic avian influenza continued to occur in domestic poultry farms and wild birds in February as well as sporadic outbreaks during the migratory bird migration period since March . Therefore , the main quarantine measures implemented during the special quarantine period will be extended until Tuesday, March 31 to continue strengthened quarantine management of poultry farms , etc.

* According to the February migratory bird habitat survey ( cooperation with the Ministry of Climate and Environment ), 1.33 million birds were confirmed , a 1.2% decrease in the number of birds compared to the previous month (1.35 million ) , but many migratory birds still live across the country.

* * Farm (50 cases ) : (September ) 1 case → (October ) 1 case → (November ) 4 cases → (December ) 22 cases → (January ) 10 cases → (February ) 12 cases

Migratory birds (59 cases ): (September ) 0 cases → (October ) 2 cases → (November ) 11 cases → (December ) 10 cases → ( January ) 19 cases → ( February ) 17 cases

*** Occurrences in the past March to May : ('23 ) 2 cases in March , 4 cases in April , ( '24 ) 1 case in May , ( '25 ) 8 cases in March , 4 cases in April

< Strengthened quarantine measures >

To prevent further sporadic outbreaks due to migratory birds moving north, the Central Disaster and Safety Countermeasure Headquarters will strengthen quarantine measures as follows until Tuesday , March 31 .

First , we will continue to operate the Central Disaster and Safety Countermeasures Headquarters for Highly Pathogenic Avian Influenza system , cooperate with relevant ministries such as the Ministry of the Interior and Safety and the Ministry of Climate Change to respond with all-out efforts across the government , and all local governments will continue to operate response headquarters and situation rooms .

Second , a special quarantine inspection will be conducted jointly by the Ministry of Agriculture, Food and Rural Affairs, the Ministry of the Interior and Safety, and other relevant organizations in 32 cities and counties at risk during the northern migration period of migratory birds (March 3 to March 17) , and a ' Quarantine Strengthening Public Relations Campaign ' will be promoted together with producer groups to improve quarantine rules for poultry farms . *

* Major farm initiatives for the month of March : ① Changing boots when entering and exiting the barn , ② General cleaning and disinfection , ③ General rat extermination work

Third , to prevent further outbreaks in laying hens, one-on-one dedicated managers will be assigned to laying hens in farms with more than 50,000 hens nationwide by March to manage vehicles and people entering and exiting the farms . In particular, control posts installed in densely populated areas and large-scale laying hens with more than 200,000 hens will be intensively inspected to ensure compliance with quarantine measures such as vehicle disinfection .

* In addition, random environmental inspections will be conducted on hazardous livestock vehicles ( egg , manure , feed transport ) and goods entering and exiting laying hen farms nationwide during March .

Fourth , the existing administrative orders (11 cases) and public notices (7 cases) that have been issued and are in effect will be extended until March , and additional administrative orders ( 2 cases ) and public notices (3 cases ) will be issued and operated to prevent outbreaks at poultry farms .

* Additional measures : ① Restriction on partial shipment of laying hens nationwide for 2 weeks (March 1 to March 14), ② Restriction on the entry of laying hens into outbreak cities and counties for 2 weeks (March 1 to March 14), ③ Restriction on entry of livestock disposal personnel to other farms for purposes other than livestock disposal for 1 month (March 1 to March 31)

- However , shipment of all laying hens from a farm to a slaughterhouse is possible , and in cases where unavoidable circumstances are recognized , movement ( shipment ) is permitted under limited circumstances under the supervision of public officials. Administrative orders and public notices may be adjusted depending on the situation.

        (Continue . . .) 

This announcement also contains special instructions for dealing with ASF and FMD.   

In an update from last week's report on pig feed additives which tested positive for ASF DNA, we have the following update which also found ASF genes in on-farm stockpiled feed.

Once again, this appears to be via PCR, meaning that the infectiousness of this sample hasn't been ascertained. 

African swine fever (ASF) genes detected in compound feed made from plasma proteins, leading to strengthened quarantine measures to prevent its spread.

2026.02.24 23:00:00 Foot-and-Mouth Disease Prevention Division, Quarantine Policy Bureau

The African Swine Fever Central Disaster and Safety Countermeasures Headquarters ( Director Song Mei-ryeong, Minister of Agriculture, Food and Rural Affairs , hereinafter referred to as the Central Disaster and Safety Countermeasures Headquarters ) announced on Tuesday , February 24 that it will strengthen quarantine measures to prevent the spread of African swine fever (ASF) after the gene was detected in pig feed .

1. Detection circumstances

The Korea Centers for Disease Control and Prevention (KCDC) is conducting a comprehensive inspection ( carcasses and environmental samples ) on pig farms nationwide . During this process , a detailed inspection was conducted on carcasses and environmental samples such as feed from a pig farm (No. 1 ) in Hongseong, South Chungcheong Province , and on February 24 , it was announced that the African swine fever (ASF) gene was detected * in two cases ( same product ) of compound feed made from plasma protein .

* Results of testing by the Chungcheongnam-do Animal Hygiene Testing Laboratory and the Animal and Plant Quarantine Agency , positive result due to detection of ASF gene

2. Key quarantine measures

The central government will first order local governments across the country to order owners of feed* in which African swine fever (ASF) genes have been detected at pig farms to dispose of the relevant items in accordance with the Livestock Infectious Disease Prevention Act ** .

* It is assumed to have been manufactured using pig-derived plasma protein supplied by OOO Lab as the raw material.

** Article 23 of the Livestock Infectious Disease Prevention Act ( Incineration of Contaminated Materials, etc. )

In addition , for feed in which African swine fever (ASF) genes have been detected, the relevant companies ( some names ), production dates , and products will be disclosed on the Animal and Plant Quarantine Agency website (www.qia.go.kr) * , and local governments plan to recommend that pig farms nationwide stop using the relevant feed as a preventive measure .

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While it may appear that South Korea's livestock disease woes are far greater than most other countries, it is worth mentioning that few countries are as open about their agricultural disease challenges and responses. 

So how much of an outlier South Korea really is, is difficult to say. 

But given the way that livestock diseases propagate around the globe, countries that are currently under less pressure may find their current status quos to be fleeting.