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Vaccine. 2017 Oct 13;35(43):5799-5807. doi: 10.1016/j.vaccine.2017.09.035. Epub 2017 Sep 20.

Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015.

Author information

1
FISABIO-Salud Pública, 46020 Valencia, Spain; Centro de Salud Pública de Castellón, 12003 Castellón, Spain. Electronic address: puig_joa@gva.es.
2
FISABIO-Salud Pública, 46020 Valencia, Spain.
3
Hospital Doctor Peset, 46017 Valencia, Spain.
4
FISABIO-Salud Pública, 46020 Valencia, Spain; CIBERESP, Instituto de Salud Carlos III, 28029 Madrid, Spain.
5
Navarrabiomed - Fundación Miguel Servet, 31008 Pamplona, Spain; REDISSEC, Instituto de Salud Carlos III, 28029 Madrid, Spain.
6
Universidad CEU-UCH, 12006 Castellón, Spain; Hospital General Universitario de Castellón, 12004 Castellón, Spain.
7
Universidad Miguel Hernández, 03202 Elche, Spain; Hospital San Juan de Alicante, 03550 Alicante, Spain.
8
Hospital Lluís Alcanyís, 46800 Xàtiva, Spain.
9
Hospital de Elda, 03600 Elda, Spain.
10
Hospital La Plana, 12540 Vila-real, Spain.
11
Hospital La Fe, 46026 Valencia, Spain.
12
Hospital General de Alicante, 03010 Alicante, Spain.

Abstract

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 18years or older who had received seasonal influenza vaccine and were subsequently admitted to the hospital for influenza infection, asassessed 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 65years or older, we found a statistically significant lower risk of admission with influenza among late vaccinees during the 2011/2012 and 2014/2015A(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 65years 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 65years old or over in two A(H3N2)-dominant influenza seasons.

KEYWORDS:

Influenza vaccine; Vaccine effectiveness; Waning protection

PMID:
28941618
DOI:
10.1016/j.vaccine.2017.09.035
[Indexed for MEDLINE]
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