High Public-Health Impact in an Influenza-B-Mismatch Season in Southern Italy, 2017-2018. (20th August 2019)

• Record Type: Journal Article
• Authors: Loconsole, Daniela; De Robertis, Anna Lisa; Morea, Anna; Casulli, Daniele; Mallamaci, Rosanna; Baldacci, Simona; Centrone, Francesca; Bruno, Viviana; Quarto, Michele; Accogli, Marisa; Chironna, Maria
• Other Names: Luo Ma Academic Editor.
• Is Part Of: BioMed research international. Volume 2019(2019)
• Publication Date: 2019-08-20
• Subjects: Medicine -- Periodicals; Biology -- Periodicals; Biotechnology -- Periodicals; Life sciences -- Periodicals; 610.5
• DOI: 10.1155/2019/4643260
• Languages: English
• ISSNs: 2314-6133

Abstract

Abstract : Background . Yearly influenza epidemics have considerable effects on public health worldwide. The 2017-2018 influenza season in Italy was of greater severity than previous seasons. The aim of this study was to describe the 2017-2018 influenza season in Southern Italy and the molecular characteristics of the circulating viral strains. Methods . The incidence of influenza-like illness (ILI) was analysed. Nasopharyngeal swabs collected from patients with ILI from week 46/2017 to week 17/2018 were tested to identify influenza A viruses (IAV) and influenza B viruses (IBV). Sequencing and phylogenetic analysis of haemagglutinin genes were also performed on 73 positive samples (35 IBV, 36 IAV H1, and 2 IAV H3 strains). Results . During the 2017-2018 season, the peak incidence was 14.32 cases per 1, 000 inhabitants. IBV strains were identified in 71.0% of cases. The 35 characterised IBV strains belonged to Yamagata lineage clade 3, the 36 A/H1N1pdm09 strains clustered with the genetic subgroup 6B.1, and the 2 A/H3N2 strains clustered with the genetic subgroup 3C.2a. Intensive-care unit (ICU) admission was required in 50 cases of acute respiratory distress syndrome (ARDS). Among the >64-year age group, 18 out of 26 ICU-ARDS cases (69.2%) were caused by IBV, and 14 of these (77.8%) were B/Yamagata lineage. Conclusions . The 2017-2018 influenza season was one of the most severe in a decade in Southern Italy. IBV mismatch between the trivalent vaccine and the circulating strains occurred. The high number of ICU-ARDS cases caused by B/Yamagata strains in the >64-year age group suggests that further data on the effectiveness of the available influenza vaccines are needed to determine the best way to protect the elderly against both IBV lineages.