Vaccine effectiveness against influenza A(H3N2) and B among laboratory-confirmed, hospitalised older adults, Europe, 2017-18: A season of B lineage mismatched to the trivalent vaccine.
Influenza Other Respir Viruses
; 14(3): 302-310, 2020 05.
Article
em En
| MEDLINE
| ID: mdl-32022450
ABSTRACT
BACKGROUND:
Influenza A(H3N2), A(H1N1)pdm09 and B viruses co-circulated in Europe in 2017-18, predominated by influenza B. WHO-recommended, trivalent vaccine components were lineage-mismatched for B. The I-MOVE hospital network measured 2017-18 seasonal influenza vaccine effectiveness (IVE) against influenza A(H3N2) and B among hospitalised patients (≥65 years) in Europe.METHODS:
Following the same generic protocol for test-negative design, hospital teams in nine countries swabbed patients ≥65 years with recent onset (≤7 days) severe acute respiratory infection (SARI), collecting information on demographics, vaccination status and underlying conditions. Cases were RT-PCR positive for influenza A(H3N2) or B; controls negative for any influenza. "Vaccinated" patients had SARI onset >14 days after vaccination. We measured pooled IVE against influenza, adjusted for study site, age, sex, onset date and chronic conditions.RESULTS:
We included 3483 patients 376 influenza A(H3N2) and 928 B cases, and 2028 controls. Most (>99%) vaccinated patients received the B lineage-mismatched trivalent vaccine. IVE against influenza A(H3N2) was 24% (95% CI 2 to 40); 35% (95% CI 6 to 55) in 65- to 79-year-olds and 14% (95% CI -22 to 39) in ≥80-year-olds. Against influenza B, IVE was 30% (95% CI 16 to 41); 37% (95% CI 19 to 51) in 65- to 79-year-olds and 19% (95% CI -7 to 38) in ≥80-year-olds.CONCLUSIONS:
IVE against influenza B was similar to A(H3N2) in hospitalised older adults, despite trivalent vaccine and circulating B lineage mismatch, suggesting some cross-protection. IVE was lower in those ≥80 than 65-79 years. We reinforce the importance of influenza vaccination in older adults as, even with a poorly matched vaccine, it still protects one in three to four of this population from severe influenza.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vírus da Influenza B
/
Vacinas contra Influenza
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Influenza Humana
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Vírus da Influenza A Subtipo H3N2
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Aged
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Aged80
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Female
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Humans
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Male
País/Região como assunto:
Europa
Idioma:
En
Revista:
Influenza Other Respir Viruses
Assunto da revista:
VIROLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França