Influenza Vaccine Effectiveness and Waning Effect in Hospitalized Older Adults. Valencia Region, Spain, 2018/2019 Season.
Int J Environ Res Public Health
; 18(3)2021 01 27.
Article
in En
| MEDLINE
| ID: mdl-33514058
ABSTRACT
Influenza vaccination is annually recommended for specific populations at risk, such as older adults. We estimated the 2018/2019 influenza vaccine effectiveness (IVE) overall, by influenza subtype, type of vaccine, and by time elapsed since vaccination among subjects 65 years old or over in a multicenter prospective study in the Valencia Hospital Surveillance Network for the Study of Influenza and other Respiratory Viruses (VAHNSI, Spain). Information about potential confounders was obtained from clinical registries and/or by interviewing patients and vaccination details were only ascertained by registries. A test-negative design was performed in order to estimate IVE. As a result, IVE was estimated at 46% (95% confidence interval (CI) (16%, 66%)), 41% (95% CI (-34%, 74%)), and 45% (95% CI (7%, 67%)) against overall influenza, A(H1N1)pdm09 and A(H3N2), respectively. An intra-seasonal not relevant waning effect was detected. The IVE for the adjuvanted vaccine in ≥75 years old was 45% (2%, 69%) and for the non-adjuvanted vaccine in 65-74 years old was 59% (-16%, 86%). Thus, our data revealed moderate vaccine effectiveness against influenza A(H3N2) and not significant against A(H1N1)pdm09. Significant protection was conferred by the adjuvanted vaccine to patients ≥75 years old. Moreover, an intra-seasonal not relevant waning effect was detected, and a not significant IVE decreasing trend was observed over time.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Influenza Vaccines
/
Influenza, Human
/
Influenza A Virus, H1N1 Subtype
Type of study:
Clinical_trials
/
Observational_studies
/
Risk_factors_studies
Limits:
Aged
/
Humans
Country/Region as subject:
Europa
Language:
En
Journal:
Int J Environ Res Public Health
Year:
2021
Document type:
Article
Affiliation country:
Spain