BACKGROUND: The influenza B viruses belong to two lineages distinguished by their genetic and antigenic characteristics, which are referred to as the Yamagata and Victoria lineages, designated after their original isolates, B/Yamagata/16/88 and B/Victoria/2/87. The primary aim of this study was to evaluate the molecular characteristics of influenza B viruses circulating in a region of Northern Italy, Lombardia, during the influenza season of 2015-2016. METHODS: Influenza B virus was detected using a respiratory virus panel of assays and an influenza B-specific real-time polymerase chain reaction. The complete influenza B hemagglutinin (HA) gene was amplified and sequenced directly from clinical specimens. Phylogenetic analysis was performed using nucleotide sequences. RESULTS: A total of 71 hospitalized pediatric patients were influenza B positive. Phylogenetic analysis showed that the great majority of influenza B strains (66/71, 93.0%) belonged to the Victoria-lineage and were antigenically like vaccine strain (B/Brisbane/60/2008) included only in the quadrivalent vaccine. In the detected influenza B strains, a series of amino acid changes were observed in the antigenic regions: I117V, V124A, N129D, V146I, N197D, T199A, and A202T. However, only 2 amino acid changes were observed in the HA regions involved in receptor binding or in antibody recognition. CONCLUSIONS: All the influenza B strains identified in this study belonged to the influenza B Victoria lineage not included in the trivalent vaccine commonly used by the general population during the 2015-2016 influenza season in Italy. This indicates that protection against influenza B infection in the vaccinated population was in general very poor during the 2015-2016 influenza season.

Molecular epidemiology of influenza B virus among hospitalized pediatric patients in Northern Italy during the 2015-16 season

Piralla, Antonio;Rovida, Francesca;Caimmi, Silvia;Marseglia, Gian Luigi;Baldanti, Fausto
;
2017-01-01

Abstract

BACKGROUND: The influenza B viruses belong to two lineages distinguished by their genetic and antigenic characteristics, which are referred to as the Yamagata and Victoria lineages, designated after their original isolates, B/Yamagata/16/88 and B/Victoria/2/87. The primary aim of this study was to evaluate the molecular characteristics of influenza B viruses circulating in a region of Northern Italy, Lombardia, during the influenza season of 2015-2016. METHODS: Influenza B virus was detected using a respiratory virus panel of assays and an influenza B-specific real-time polymerase chain reaction. The complete influenza B hemagglutinin (HA) gene was amplified and sequenced directly from clinical specimens. Phylogenetic analysis was performed using nucleotide sequences. RESULTS: A total of 71 hospitalized pediatric patients were influenza B positive. Phylogenetic analysis showed that the great majority of influenza B strains (66/71, 93.0%) belonged to the Victoria-lineage and were antigenically like vaccine strain (B/Brisbane/60/2008) included only in the quadrivalent vaccine. In the detected influenza B strains, a series of amino acid changes were observed in the antigenic regions: I117V, V124A, N129D, V146I, N197D, T199A, and A202T. However, only 2 amino acid changes were observed in the HA regions involved in receptor binding or in antibody recognition. CONCLUSIONS: All the influenza B strains identified in this study belonged to the influenza B Victoria lineage not included in the trivalent vaccine commonly used by the general population during the 2015-2016 influenza season in Italy. This indicates that protection against influenza B infection in the vaccinated population was in general very poor during the 2015-2016 influenza season.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1211252
Citazioni
  • ???jsp.display-item.citation.pmc??? 9
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 8
social impact