Influenza epidemiology and influenza vaccine effectiveness during the 2015-2016 season: results from the Global Influenza Hospital Surveillance Network


Puig-Barbera J., Mira-Iglesias A., Burtseva E., Cowling B. J. , Serhat U., Ruiz-Palacios G. M. , ...More

BMC INFECTIOUS DISEASES, vol.19, 2019 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 19
  • Publication Date: 2019
  • Doi Number: 10.1186/s12879-019-4017-0
  • Journal Name: BMC INFECTIOUS DISEASES
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Keywords: Influenza, Virus, Surveillance, Vaccine, Hospitalization, Epidemiological study, UNITED-STATES, VIRUSES, INFECTION, LINEAGE

Abstract

BackgroundThe Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization.MethodsDuring the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach.Results9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were<5years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, -3.6 to 32.2) overall, 23.0% (95% CI, -3.3 to 42.6) against A(H1N1)pdm09, and-25.6% (95% CI, -86.3 to 15.4) against B/Victoria lineage.ConclusionsThe 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.