New H5N1 genotype spreads
Reporting says a new highly pathogenic H5N1 genotype called D1.1 has rapidly spread across migratory-bird routes in the United States and Canada, prompting renewed pandemic-preparedness concerns. (downtoearth.org.in) The FDA has granted fast-track status to ARCT-2304 for H5N1 protection while the CDC notes there is no approved H5N1 vaccine for the general public yet, and separate reporting records a poultry outbreak in Ivory Coast that killed about 95,000 birds. ( )
Bird flu is changing again in North America: researchers say a new H5N1 genotype called D1.1 spread across U.S. and Canadian migratory-bird routes during the 2024 fall migration and displaced earlier strains. (nature.com) H5N1 is an avian influenza virus, a flu virus that mainly circulates in birds but can also infect mammals and, in rare cases, people. The World Health Organization says the clade now circulating globally has caused unusually large die-offs in wild birds and poultry since 2020 and reached North America in 2021. (who.int) The new D1.1 genotype was first detected in September 2024. In the Nature Medicine study, researchers using surveillance data from Canada and the United States said it formed a single lineage and spread south and east across several flyways, starting in Alaska and British Columbia. (nature.com, stjude.org) The paper said D1.1’s expansion coincided with detections in other hosts, including 17 human cases, four of them severe or fatal. The authors also said the mammalian-adaptive changes seen in some human infections were not found in the wild-bird viruses they analyzed. (nature.com) St. Jude, whose researchers helped map the spread, said current human vaccine stockpiles are likely to remain a good match against D1.1 and that the strain appears low risk for human-to-human spread in its current form. The Centers for Disease Control and Prevention separately says there is no known person-to-person spread at this time. (stjude.org, cdc.gov) The Centers for Disease Control and Prevention says the current public-health risk to the general public is low, but the virus is still causing outbreaks in poultry and U.S. dairy cows with sporadic human cases in exposed workers. As of its March 6, 2026 update, the agency listed 71 U.S. human cases since 2024 and two deaths. (cdc.gov) Vaccine development is still moving. On April 10, 2025, Arcturus Therapeutics said the Food and Drug Administration granted Fast Track designation to ARCT-2304, an investigational H5N1 vaccine that had already entered a Phase 1 study in November 2024. (businesswire.com) That does not mean a shot is available at pharmacies. The Centers for Disease Control and Prevention says there is no approved or recommended H5N1 vaccine for the general public, though it has prepared candidate vaccine viruses that could be used to make doses if needed. (cdc.gov, contagionlive.com) The virus is still hitting poultry outside North America too. Reuters reported on April 16, 2026 that Ivory Coast notified the World Organisation for Animal Health of an H5N1 outbreak on a farm in Koun-Fao near the Ghana border that killed 95,000 birds. (aol.com) For now, the picture is two-track: D1.1 has become the dominant wild-bird strain across much of North America, while public-health agencies still say the immediate risk to the broader public remains low and are watching for any sign that the virus starts spreading more easily in people. (nature.com, cdc.gov)
