Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy

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RESEARCH PRODUCT

Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy

S. Bellino A. Bella S. Puzelli A. Di Martino M. Facchini O. Punzo P. Pezzotti M.r. Castrucci G. Di Mario L. Calzoletti C. Fabiani M. Chironna C. Germinario F. Tramuto V. Di Carlo P. Affanni M. Grazia Pascucci P. D'agaro T. Gallo E. Pagani B. Natter B. Camilloni A. Tosti E. Pariani S. Senatore C. Serra P. Rita Tanchis V. Ghisetti D. Tiberti L. Romano E. Volpe S. Giannecchini

subject

Male test-negative case-control study 0301 basic medicine Prevalence Influenza vaccine effectiveness test-negative case-control study national influenza surveillance network Italy Settore MED/42 - Igiene Generale E Applicata Influenza A Virus H1N1 Subtype 0302 clinical medicine Drug Discovery Epidemiology 030212 general & internal medicine Child Influenza vaccine effectiveness Aged 80 and over national influenza surveillance network Age Factors virus diseases Middle Aged 3. Good health Vaccination Treatment Outcome Italy Influenza Vaccines Child Preschool Molecular Medicine Female Influenza vaccine effectiveness; Italy; national influenza surveillance network; test-negative case-control study Adult medicine.medical_specialty Adolescent Influenza vaccine Immunology Context (language use)Virus Young Adult 03 medical and health sciences Internal medicine Influenza Human medicine Animals Humans Aged Pharmacology business.industry Influenza A Virus H3N2 Subtype Case-control study Infant 030104 developmental biology Immunization Case-Control Studies business

description

Background: Influenza vaccines are updated every year to match the vaccine strains with currently circulating viruses; consequently influenza vaccine effectiveness (IVE) has to be assessed annually.Research design and methods: A test-negative case-control study was conducted within the context of the Italian sentinel influenza surveillance network to estimate IVE by age group, virus subtype, and vaccine brand in medically attended laboratory-confirmed influenza.Results: In Italy, the 2018/19 influenza season was characterized by the co-circulation of influenza A(H1N1)pdm09 and A(H3N2) viruses. The adjusted IVE estimate in preventing influenza was moderate (44.8%, 95% CI: 18.8 to 62.5) against A(H1N1)pdm09, whereas there was no evidence of effectiveness (1.8%, 95% CI: -37.8 to 30.1) in persons affected by A(H3N2). IVE against A(H1N1)pdm09 decreased with age ranging from 65.7% to 13.1% among children/adolescents and elderly, respectively; moreover results suggest that Vaxigrip Tetra® was more effective against A(H1N1)pdm09 compared to Fluarix Tetra® [62.5% (95% CI: 34.3 to 78.6) vs 24.5% (95% CI: -40.6 to 59.6)]. Low effectiveness (35.2%, 95% CI: -50.8 to 72.1) against A(H3N2) was detected only in the elderly immunized with Fluad®.Conclusions: Findings suggest that influenza vaccines were low to moderately effective, probably due to a mismatch between circulating and vaccine strains.

year	journal	country	edition	language
2019-11-02	Expert Review of Vaccines

10.1080/14760584.2019.1688151 http://dx.doi.org/10.1080/14760584.2019.1688151