1. Influenza vaccine effectiveness in Italy: Age, subtype-specific and vaccine type estimates 2014/15 season.
- Author
-
Rizzo C, Bella A, Alfonsi V, Puzelli S, Palmieri AP, Chironna M, Pariani E, Piatti A, Tiberti D, Ghisetti V, Rangoni R, Colucci ME, Affanni P, Germinario C, and Castrucci MR
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Case-Control Studies, Child, Child, Preschool, Humans, Infant, Influenza A Virus, H1N1 Subtype, Influenza A Virus, H3N2 Subtype, Influenza B virus, Italy epidemiology, Middle Aged, Sentinel Surveillance, Young Adult, Influenza Vaccines therapeutic use, Influenza, Human epidemiology, Influenza, Human prevention & control
- Abstract
The 2014/15 influenza season in Europe was characterised by the circulation of influenza A(H3N2) viruses with an antigenic and genetic mismatch from the vaccine strain A/Texas/50/2012(H3N2) recommended for the Northern hemisphere for the 2014/15 season. Italy, differently from other EU countries where most of the subtyped influenza A viruses were H3N2, experienced a 2014/15 season characterized by an extended circulation of two influenza viruses: A(H1N1)pdm09 and A(H3N2), that both contributed substantially to morbidity. Within the context of the existing National sentinel influenza surveillance system (InfluNet) a test-negative case-control study was established in order to produce vaccine effectiveness (VE) estimates. The point estimates VE were adjusted by age group (<5; 5-15; 15-64; 65+ years), the presence of at least one chronic condition, target group for vaccination and need help for walking or bathing. In Italy, adjusted estimates of the 2014/15 seasonal influenza VE against medically attended influenza-like illness (ILI) laboratory-confirmed as influenza for all age groups were 6.0% (95%CI: -36.5 to 35.2%), 43.6% (95%CI: -3.7 to 69.3%), -84.5% (95%CI: (-190.4 to -17.2%) and 50.7% (95% CI: -2.5 to 76.3%) against any influenza virus, A(H1N1)pdm09, A(H3N2) and B, respectively. These results suggest evidence of good VE against A(H1N1)pdm09 and B viruses in Italy and evidence of lack of VE against A(H3N2) virus due to antigenic and genetic mismatch between circulating A(H3N2) and the respective 2014/15 vaccine strain., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF