BREAKING! New H1N1 Flu Strains That Emerged in Late 2024 and Early 2025 Trigger Diagnostic Failures in Testing Kits!
Nikhil Prasad Fact checked by:Thailand Medical News Team Apr 11, 2025 1 day, 22 hours, 6 minutes ago
Medical News: Unsubtypeable Flu Strains Raise Alarm Among Diagnostic Experts
In an alarming development from South Korea, researchers have discovered that newly emerging strains of the H1N1 influenza virus are causing failures in one of the most commonly used commercial molecular diagnostic kits. The new H1N1 strains—scientifically categorized as subclades 6B.1 A.5a.2a and 6B.1 A.5a.2a.1—were found to evade detection by the Allplex Respiratory Panel 1 (RP1), a multiplex PCR assay widely used to identify and subtype flu viruses.
BREAKING! New H1N1 Flu Strains That Emerged in Late 2024 and Early 2025 Trigger Diagnostic Failures in Testing Kits!
Thailand
Medical News had warned in November 2024 that there were new H1N1 and H3N2 flu strains in circulation but our warnings were overshadowed by pharma companies and also health officials trying to cover up that the existing flu vaccines were not effective in protecting against infections by these new flu strains that were also causing a slight increase in disease severity!
However, a team of scientists from the Korea Disease Control and Prevention Agency, Seegene Inc., and several South Korean clinical laboratories made the discovery while analyzing nasopharyngeal swabs collected between August 2023 and December 2024 and made public the findings via a published peer reviewed study. The analyzed specimens tested positive for influenza A but could not be classified as either H1N1 or H3N2 by the Allplex RP1 test. Subsequent analysis by other teams of HIN1 flu strains in circulation in early 2025 also validated the presence of new H1N1 strains! This
Medical News report sheds light on a potentially troubling issue for global flu surveillance and diagnostic accuracy.
Hidden Mutations Interfering with Test Accuracy
In the Korean study, out of 194 influenza A-positive samples identified using the Allplex RP1, 23 samples could not be subtyped. The team conducted further analysis using alternative PCR tests and gene sequencing. In 22 of these 23 cases, they successfully amplified the virus’ M and HA genes and confirmed the presence of the influenza A(H1N1)pdm09 strain—despite the Allplex RP1 kit failing to detect it. The remaining sample likely had a viral load too low for confirmatory testing.
Upon close genetic inspection, scientists discovered specific mutations in the HA gene—particularly within regions targeted by the test’s primers and probes. These subtle yet impactful genetic changes disrupted the ability of the commercial assay to recognize the virus, even though it was not a completely new or foreign strain.
All 22 successfully sequenced viruses belonged to the two subclades that have now become dominant in the region—6B.1 A.5a.2a.1 and 6B.1 A.5a.2a. As of late November 2024, nearly all H1N1pdm09 viruses circulating in South Korea fall under these classifications. This finding explains why the test failed despite the virus being very much present and circu
lating widely.
Commercial Testing Vulnerabilities Exposed
The study highlights a fundamental issue in influenza diagnostics: unlike COVID-19 tests which often rely on detecting multiple gene targets, flu subtyping assays generally focus on a single gene. This design makes them more vulnerable to failures when viruses mutate at specific locations. These subtyping failures do not necessarily indicate a new or zoonotic (animal-origin) strain, but they do underline the critical importance of continuous viral surveillance and rapid test adaptation.
This is especially vital as global attention shifts from COVID-19 to ongoing and resurging threats like seasonal influenza. As pathogens evolve, even minor genetic shifts can interfere with detection tools—leading to inaccurate results, delayed responses, and potential public health consequences.
Implications and the Road Ahead
While the study emphasizes that the failed subtyping did not signal the emergence of a new flu virus, the implications for diagnostic accuracy and disease tracking are profound. With nearly half of H1N1 cases in South Korea now represented by these two mutant subclades, the need for continual monitoring and updating of diagnostic assays has become urgent.
Researchers warn that similar diagnostic failures could occur elsewhere as these subclades spread globally. They recommend regular genomic surveillance, prompt updates to commercial assay designs, and awareness among clinicians and diagnostic labs regarding possible mismatches between evolving virus strains and current test kits.
In conclusion, while the findings do not point to an immediate major new pandemic threat, they underscore how even small viral changes can outsmart our diagnostic tools. Ongoing mutation-driven failures in influenza subtyping could undermine disease surveillance efforts unless swiftly addressed through technological and procedural updates. The study also serves as a reminder of the delicate balance between viral evolution and human preparedness.
Health officials in countries in Northern America, Europe and Asia should be more transparent about genomic data of pathogens causing outbreaks and stop concealing critical information just to serve the interest of the big pharma. We also need a better platform than GISAID that is not manipulated by government agencies or big pharma so that all actual sequenced samples are upload and nothing is concealed.
The study findings were published in the peer reviewed Journal of Clinical Virology.
https://www.sciencedirect.com/science/article/abs/pii/S1386653225000393
For the latest Influenza News, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/news/japanese-study-finds-that-baloxavir-outperforms-oseltamivir-in-treating-influenza-among-children
https://www.thailandmedical.news/news/beta-glucans-found-in-mushrooms-can-reprogram-neutrophils-to-combat-influenza-a-viruses
https://www.thailandmedical.news/news/canadian-researchers-discover-new-h5n1-bird-flu-strains-resistant-to-oseltamivir-tamiflu
https://www.thailandmedical.news/news/delhi-witnessing-an-anomalous-flu-surge-as-many-remaining-sick-over-longer-periods-along-with-persistent-fevers
https://www.thailandmedical.news/articles/influenza-or-flu
https://www.thailandmedical.news/pages/thailand_doctors_listings
Share
Tweet
Share
