Vietnam Creates Chimeric Bird Flu Hybrid That Multiplies 800% More Efficiently Using U.S. Reverse Genetics System: Journal 'Veterinary Research Forum'
St. Jude's Dr. Richard Webby supplies genetic engineering platform for generating never-before-seen H5N1 avian influenza Frankenviruses in Southern Asia.
A Veterinary Research Forum study published in October confirms that Vietnamese researchers have engineered a new generation of chimeric H5N1 bird flu viruses by fusing avian and human influenza genes—enhancing the virus’s replication efficiency more than eight-fold using U.S.-origin reverse-genetics technology.
The generation of new H5N1 pathogens comes as bird flu research is expected to surge 1,000% by 2030.
The 2025 study, titled “Enhanced hemagglutination titers of avian influenza A (H5N1) viruses grown in eggs by replacing the noncoding regions of neuraminidase,” describes the construction of what the authors call recombinant viruses, which are viruses genetically engineered to carry genes from different sources.
The recombinant viruses in the study combine H5N1 neuraminidase (NA) genes from a Vietnamese strain with the non-coding terminal sequences of A/Puerto Rico/8/1934 (PR8)—a human influenza strain commonly used as a vaccine seed virus.
“Chimeric neuraminidase (NA) genes were generated by replacing the 5’ and 3’ packaging signals of PR8 A/PR/8/34 strain with the coding region of the NA genes of ST-2009,” the authors wrote, adding that the resulting hybrids “exhibited significantly greater hemagglutination titers in embryonated chicken eggs” than the control virus.
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Recombinant ‘Frankenvirus’ Construction
The team claims to have created four hybrid recombinant viruses (RV1–RV4) using the eight-plasmid reverse-genetics system first pioneered by Dr. Yoshihiro Kawaoka and Dr. Erich Hoffmann.
They accomplished this by co-transfecting 293T human kidney cells with eight DNA plasmids encoding the viral genes.
Two of those plasmids carried chimeric NA and HA genes from the Vietnamese H5N1 strain A/duck/Vietnam/ST0907/2009 (clade 1.1)—while the other six came from the human PR8 backbone, effectively merging avian and human influenza genomes.
“The generation of re-assorted 6 + 2 vaccine viruses involved the co-transfection of 293T cells with eight cDNA plasmids,” the paper states. “Two plasmids were encoded using the chimeric NA and HA of ST-2009 or IBT-RG1, together with the six gene plasmids of PR8.”
The resulting viruses were grown in 10- to 11-day-old embryonated chicken eggs and tested for their ability to agglutinate red blood cells—a standard measure of viral propagation efficiency.
Documented Gain of Function
According to the data, the engineered viruses produced dramatically higher viral yields.
The wild-type ST-2009 H5N1 strain had a negative hemagglutination (HA) titer, meaning it could not replicate efficiently in eggs.
But after genetic modification with PR8’s terminal sequences, viral titers rose to between 3.1 and 4.2 log₂ units—a more than fourfold increase in replication efficiency.
A second experiment using a different recombinant strain (IBT-RG01) achieved even higher titers, climbing from 6.22 to 8.16 log₂ after the same genetic substitutions.
“The inclusion of the ST-2009 NA ORF, which is surrounded by the PR8 NA 5′ and 3′ packaging signals, has a substantial impact on the hemagglutination titer of the virus,” the authors concluded.
Although presented as a method to “improve vaccine yields,” these genetic manipulations clearly enhanced viral replication—a hallmark of gain-of-function (GOF) research.
Cross-Species Chimeras
The scientists claim to have effectively fused the genetic elements of a highly pathogenic avian H5N1 virus with a human influenza strain, blurring the species barrier between bird and human viruses.
The authors say that the chimeric constructs consisted of avian H5N1 open reading frames (ORFs) flanked by human PR8 non-coding regions (NCRs) on both ends—41 nucleotides at the 5′ end and 67 at the 3′.
These non-coding regions act as packaging signals that are said to determine how viral genes are incorporated into new virus particles.
In simple terms, the researchers borrowed the “assembly instructions” from a human influenza virus and attached them to an avian flu gene—creating a hybrid genome that assembled more efficiently than the natural H5N1.
“Replacing the PR8 NCR for vaccine viruses with low yield growth in eggs was critical,” they wrote. “The packaging efficiency of new viruses containing chimeric NA was significantly greater than that of the control virus.”
Conducted in Vietnam With U.S. Reverse-Genetics Tools
All experiments were performed at the Institute of Biotechnology (IBT), part of the Vietnam Academy of Science and Technology in Hanoi.
The authors acknowledged U.S. virologist Dr. Richard Webby of St. Jude Children’s Research Hospital in Memphis, Tennessee, for supplying the pHW2000 reverse-genetics plasmid system—the same eight-plasmid method used in laboratories worldwide to create synthetic influenza viruses from cloned DNA.
Dr. Webby, who is at the center of international bird flu pathogen manipulation, also serves as Director of the WHO’s Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds.
“The authors wish to acknowledge Dr. Richard Webby … for providing the pHW2000 plasmids and reverse genetics technique.”
This marks another example of American GOF technology being exported overseas, echoing previous U.S. collaborations in Asia that have raised biosecurity concerns.
Bottom Line
This study demonstrates that researchers in developing nations are now conducting sophisticated gene-swapping experiments on live H5N1 viruses using imported reverse-genetics systems—creating chimeric strains with enhanced replication capacity.
While the authors frame their work as “vaccine optimization,” the same modifications could theoretically increase transmissibility or host adaptability, particularly since PR8 is a human virus backbone.
The study also confirms that such research continues unabated in Southeast Asia even after repeated warnings about the pandemic potential of gain-of-function influenza work.
In short, Vietnam’s scientists—using U.S.-supplied reverse-genetics technology—claim to have successfully created a more replication-efficient chimeric H5N1 virus, proving that the very same tools used for vaccine research can also enhance pathogenicity.
Though framed as vaccine research, the work represents a clear example of gain-of-function experimentation on one of the world’s most dangerous pathogens—with uncertain containment and potentially far-reaching implications for global biosecurity.
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Wow, I guess this fits the definition of Luciferian Teamwork!
Looks like all the nations are working together for our next PLANdemic.
Thank you for staying in the trenches, Jon!
So...helping kids beat cancer is just a front for the real work being done at St Jude's by creating pathogens that are 100% fatal.? Have we entered a dark world where man will just destroy all living things? Being benevolent and destructive at the same time is illogical.