Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015
Background: Concerns have been raised about intraseasonal waning of the protection conferred by influenza vaccination. Methods: During four influenza seasons, we consecutively recruited individuals aged 18 years or older who had received seasonal influenza vaccine and were subsequently admitted to t...
| Authors: | , , , , , , , , , , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2017 |
| Country: | España |
| Institution: | Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO) |
| Repository: | r-FISABIO. Repositorio Institucional de Producción Científica |
| OAI Identifier: | oai:fisabio.fundanetsuite.com:p2218 |
| Online Access: | https://fisabio.portalinvestigacion.com/publicaciones/2218 |
| Access Level: | Open access |
| Keyword: | Influenza vaccine Vaccine effectiveness Waning protection |
| Summary: | Background: Concerns have been raised about intraseasonal waning of the protection conferred by influenza vaccination. Methods: During four influenza seasons, we consecutively recruited individuals aged 18 years or older who had received seasonal influenza vaccine and were subsequently admitted to the hospital for, influenza infection, as assessed by reverse transcription polymerase chain reaction. We estimated the adjusted odds ratio (aOR) of influenza infection by date of vaccination, defined by tertiles, as early, intermediate or late vaccination. We used a test-negative approach with early vaccination as reference to estimate the aOR of hospital admission with influenza among late vaccinees. We conducted sensitivity analyses by means of conditional logistic regression, Cox proportional hazards regression, and using days between vaccination and hospital admission rather than vaccination date. Results: Among 3615 admitted vaccinees, 822 (23%) were positive for influenza. We observed a lower risk of influenza among late vaccinees during the 2011/2012 and 2014/2015A(H3N2)-dominant seasons: aOR = 0.68 (95% CI: 0.47-1.00) and 0.69 (95% CI: 0.50-0.95). We found no differences in the risk of admission with influenza among late versus early vaccinees in the 2012/2013A(H1N1)pdm09-dominant or 2013/2014B/Yamagata lineage -dominant seasons: aOR =1.18 (95% CI: 0.58-2.41) and 0.98 (95% CI: 0,56-1.72). When we restricted our analysis to individuals aged 65 years or older, we found a statistically significant lower risk of admission with influenza among late vaccinees during the 2011/2012 and 2014/2015 A(H3N2)-dominant seasons: aOR = 0.61 (95% CI: 0.41-0.91) and 0.69 (95% CI: 0.49-0.96). We observed 39% (95% CI: 9-59%) and 31% (95% CI: 5-50%) waning of vaccine effectiveness among participants aged 65 years or older during the two A(H3N2)-dominant seasons. Similar results were obtained in the sensitivity analyses. Conclusion: Waning of vaccine protection was observed among individuals aged 65 years old or over in two A(H3N2)-dominant influenza seasons. (C) 2017 The Author(s). Published by Elsevier Ltd. |
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