biostudies-literature00560Unknown17(4)Valli MBEmerging infectious diseases749-51https://www.ebi.ac.uk/biostudies/studies/S-EPMC3377393biostudies-literatureHemagglutinin 222 variants in pandemic (H1N1) 2009 virus.PMC3377393Selleri MZaccaro PLalle EValli MBCapobianchi MRMeschi SMenzo SVincenti D56falseHemagglutinin 222 variants in pandemic (H1N1) 2009 virus.2011-01-01T00:00:00Z2011 Apr2024-11-06T18:58:37.511Z2022-02-11T15:42:59.791ZS-EPMC33773932147048110.3201/eid1706.10078410.3201/eid1704.100784