An 18-year-old man has been hospitalized with H5 influenza causing severe pneumonia. The patient is from the Mekong Delta region and was in contact with a flock of poultry diagnosed with H5N1 avian influenza following high mortality. The most recent case case of human H5N1 in Vietnam was reported in March.
Virologists have identified a reassortant H5N1 within the greater Mekong region that infects both poultry and humans. The isolate combines genes of clade 2.3.2.1c that has circulated for years in Asia with the more recent clade 2.3.4.4b introduced by migratory birds and now endemic in poultry since 2022.