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.
Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy / Bellino S , Bella A, Puzelli S, Di Martino A, Facchini M, Punzo O, Pezzotti P, Castrucci MR, Di Mario G, Calzoletti L. Fabiani C. Chironna M, Germinario C, Tramuto F, Di Carlo V, Affanni P, Pascucci MG, D'Agaro P, Gallo T, Pagani E, Natter B, Camilloni B, Tosti A, Pariani E, Senatore S, Serra C, Tanchis PR, Ghisetti V, Tiberti, D, Romano L, Volpe E, Giannecchini S.. - In: EXPERT REVIEW OF VACCINES. - ISSN 1744-8395. - ELETTRONICO. - 12:(2019), pp. 1-9.
Moderate influenza vaccine effectiveness against A(H1N1)pdm09 virus, and low effectiveness against A(H3N2) subtype, 2018/19 season in Italy
Di Martino A;Pagani E;Senatore S;Serra C;Romano L;Giannecchini S.
2019
Abstract
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.
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
