❓WHAT HAPPENED: Researchers in Japan have engineered a new strain of bird flu, combining genetic material from two wild viruses to create a pathogen known as Vac-3.
👤WHO WAS INVOLVED: Japanese scientists, U.S. National Institutes of Health (NIH)- funded researchers, and U.S. institutions such as the University of Georgia, Mount Sinai, and Texas Biomed.
📍WHEN & WHERE: The study was published last week in NPJ Vaccines, involving experiments conducted in Japan.
🎯IMPACT: The research raises biosecurity concerns over gain-of-function experiments and the potential for man-made pandemics.
A recent study published in NPJ Vaccines reveals that Japanese scientists have engineered a novel strain of bird flu by combining the genetic components of two different wild influenza viruses. The synthetic virus, designated Vac-3, was created in the lab, propagated in chicken eggs, and inactivated with formalin for use as a whole-particle vaccine in long-term tests involving nonhuman primates. This strain—formally named A/duck/Hokkaido/Vac-3/2007 (H5N1)—was artificially assembled and does not occur in nature.
This development comes in the wake of disclosures about U.S. government-funded experiments involving lab-created H5N1 bird flu variants. Some of those strains reportedly caused 100 percent mortality in exposed mammals. In those cases, scientists employed synthetic DNA to construct the viruses and, under a $59 million federal contract, deliberately infected live cows. Japan has also been cooperating with U.S. researchers on additional influenza-related projects, including hybrid viruses combining horse and human flu genes that reportedly replicate much faster than naturally occurring strains.
The Japanese research team emphasized that Vac-3 stimulated more robust immune responses than current flu vaccines, mainly because it retained its full genetic content, including viral RNA. Their approach, called whole-particle vaccination, is designed to activate the body’s innate immune sensors and “rewire” immune responses.
Though the term “gain-of-function” is not used in the study, the methodology behind Vac-3 fits the criteria. The virus was produced by merging genes from different influenza viruses to enhance its immunogenic properties. According to a 2025 Executive Order from the White House, gain-of-function research includes work that alters a virus’s interaction with the immune system, such as increasing its ability to evade or overactivate immune defenses.
The research also introduces significant biosecurity concerns. In their testing, scientists exposed macaques to a deadly H5N1 strain to evaluate how long immunity from Vac-3 would last. This involved constructing a virus that had never previously existed, infecting primates with it, and later challenging them with a lethal strain, all conducted within a biosafety level 3 (BSL-3) laboratory. While the stated goal was vaccine development, such experiments could trigger future pandemics.
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