Mid-Season Estimates of Influenza Vaccine Effectiveness against Influenza A(H3N2) Hospitalization in the Elderly in Quebec, Canada, January 2015
| Autor: | Monique Douville-Fradet, Danuta M. Skowronski, Rachid Amini, Isabelle Rouleau, Christine Martineau, Gaston De Serres, Rodica Gilca, Nicole Boulianne, Hugues Charest |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Male
medicine.medical_specialty Influenza vaccine Science Nose medicine.disease_cause Internal medicine Epidemiology Influenza Human medicine Influenza A virus Humans Intensive care medicine Aged Geriatrics Aged 80 and over Multidisciplinary business.industry Influenza A Virus H3N2 Subtype Quebec Influenza a medicine.disease Comorbidity Hospitalization medicine.anatomical_structure Specimen collection Influenza Vaccines Medicine Female business Sentinel Surveillance Research Article |
| Zdroj: | PLoS ONE PLoS ONE, Vol 10, Iss 7, p e0132195 (2015) |
| ISSN: | 1932-6203 |
| Popis: | BackgroundThe 2014/15 influenza season in Canada was characterized by an early epidemic due to vaccine-mismatched influenza A(H3N2) viruses, disproportionately affecting elderly individuals ≥65-years-old. We assessed vaccine effectiveness (VE) against A(H3N2) hospitalization among elderly individuals during the peak weeks of the 2014/15 epidemic in Quebec, Canada.MethodsNasal specimens and clinical/epidemiological data were collected within 7 days of illness onset from elderly patients admitted with respiratory symptoms to one of four participating hospitals between November 30, 2014 and January 13, 2015. Cases tested RT-PCR positive for influenza A(H3N2) and controls tested negative for any influenza. VE was assessed by test-negative case-control design.ResultsThere were 314 participants including 186 cases (62% vaccinated) and 128 controls (59% vaccinated) included in primary VE analysis. Median age was 81.5 years, two-thirds were admitted from the community and 91% had underlying comorbidity. Crude VE against A(H3N2) hospitalization was -17% (95%CI: -86% to 26%), decreasing to -23% (95%CI: -99 to 23%) with adjustment for age and comorbidity, and to -39% (95%CI: -142 to 20%) with additional adjustment for specimen collection interval, calendar time, type of residence and hospital. In sensitivity analyses, VE estimates were improved toward the null with restriction to participants admitted from the community (-2%; 95%CI: -105 to 49%) or with specimen collection ≤4 days since illness onset (- 8%; 95%CI: -104 to 43%) but further from the null with restriction to participants with comorbidity (-51%; 95%CI: -169 to 15%).ConclusionThe 2014/15 mismatched influenza vaccine provided elderly patients with no cross-protection against hospitalization with the A(H3N2) epidemic strain, reinforcing the need for adjunct protective measures among high-risk individuals and improved vaccine options. |
| Databáze: | OpenAIRE |
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