We report on a 2023 outbreak of severe hand, foot, and mouth disease in southern Vietnam caused by an emerging lineage of enterovirus A71 subgenogroup B5. Affected children were significantly older than those reported during previous outbreaks. The virus should be closely monitored to assess its potential for global dispersal.
Keywords: Vietnam; emerging infections; enteric infections; enterovirus A71; enteroviruses; hand foot and mouth disease; outbreaks; subgenogroup B5; viruses.