Estimating the influenza vaccine effectiveness in elderly on a yearly basis using the Spanish influenza surveillance network—Pilot case–control studies using different control groups, 2008–2009 season, Spain

Vaccine ◽  
2010 ◽  
Vol 28 (16) ◽  
pp. 2903-2907 ◽  
Author(s):  
Camelia Savulescu ◽  
Marta Valenciano ◽  
Salvador de Mateo ◽  
Amparo Larrauri
Keyword(s):  
Influenza Vaccine ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Influenza Surveillance ◽  
Case Control Studies ◽  
Control Groups ◽  
Surveillance Network ◽  
Spanish Influenza

scholarly journals A probability model for evaluating the bias and precision of influenza vaccine effectiveness estimates from case-control studies

2014 ◽  
Vol 143 (7) ◽  
pp. 1417-1426 ◽  
Author(s):  
M. HABER ◽  
Q. AN ◽  
I. M. FOPPA ◽  
D. K. SHAY ◽  
J. M. FERDINANDS ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Medical Care ◽  
Randomized Clinical Trials ◽  
Probability Model ◽  
Control Design ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Case Control Studies ◽  
Respiratory Illnesses ◽  
Study Designs

SUMMARYAs influenza vaccination is now widely recommended, randomized clinical trials are no longer ethical in many populations. Therefore, observational studies on patients seeking medical care for acute respiratory illnesses (ARIs) are a popular option for estimating influenza vaccine effectiveness (VE). We developed a probability model for evaluating and comparing bias and precision of estimates of VE against symptomatic influenza from two commonly used case-control study designs: the test-negative design and the traditional case-control design. We show that when vaccination does not affect the probability of developing non-influenza ARI then VE estimates from test-negative design studies are unbiased even if vaccinees and non-vaccinees have different probabilities of seeking medical care against ARI, as long as the ratio of these probabilities is the same for illnesses resulting from influenza and non-influenza infections. Our numerical results suggest that in general, estimates from the test-negative design have smaller bias compared to estimates from the traditional case-control design as long as the probability of non-influenza ARI is similar among vaccinated and unvaccinated individuals. We did not find consistent differences between the standard errors of the estimates from the two study designs.

scholarly journals “I-MOVE” towards monitoring seasonal and pandemic influenza vaccine effectiveness: lessons learnt from a pilot multi-centric case-control study in Europe, 2008-9

2009 ◽  
Vol 14 (44) ◽  
Author(s):  
E Kissling ◽  
M Valenciano ◽  
J M Falcão ◽  
A Larrauri ◽  
K Widgren ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Functional Status ◽  
Pandemic Influenza ◽  
Pooled Analysis ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Age Group ◽  
Case Control Studies ◽  
Statistical Heterogeneity ◽  
Negative Controls

Within I-MOVE (European programme to monitor seasonal and pandemic influenza vaccine effectiveness (IVE)) five countries conducted IVE pilot case-control studies in 2008-9. One hundred and sixty sentinel general practitioners (GP) swabbed all elderly consulting for influenza-like illness (ILI). Influenza confirmed cases were compared to influenza negative controls. We conducted a pooled analysis to obtain a summary IVE in the age group of ≥65 years. We measured IVE in each study and assessed heterogeneity between studies qualitatively and using the I2 index. We used a one-stage pooled model with study as a fixed effect. We adjusted estimates for age-group, sex, chronic diseases, smoking, functional status, previous influenza vaccinations and previous hospitalisations. The pooled analysis included 138 cases and 189 test-negative controls. There was no statistical heterogeneity (I2=0) between studies but ILI case definition, previous hospitalisations and functional status were slightly different. The adjusted IVE was 59.1% (95% CI: 15.3-80.3%). IVE was 65.4% (95% CI: 15.6-85.8%) in the 65-74, 59.6% (95% CI: -72.6 -90.6%) in the age group of ≥75 and 56.4% (95% CI: -0.2-81.3%) for A(H3). Pooled analysis is feasible among European studies. The variables definitions need further standardisation. Larger sample sizes are needed to achieve greater precision for subgroup analysis. For 2009-10, I-MOVE will extend the study to obtain early IVE estimates in groups targeted for pandemic H1N1 influenza vaccination.

scholarly journals Influenza vaccine effectiveness estimates in the Dutch population from 2003 to 2014: The test-negative design case-control study with different control groups

Vaccine ◽  
2017 ◽  
Vol 35 (21) ◽  
pp. 2831-2839 ◽  
Author(s):  
Eva van Doorn ◽  
Maryam Darvishian ◽  
Frederika Dijkstra ◽  
Gé A. Donker ◽  
Pieter Overduin ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Case Control Study ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Dutch Population ◽  
Control Groups ◽  
Design Case ◽  
Control Study

scholarly journals Early 2016/17 vaccine effectiveness estimates against influenza A(H3N2): I-MOVE multicentre case control studies at primary care and hospital levels in Europe

2017 ◽  
Vol 22 (7) ◽  
Author(s):  
Esther Kissling ◽  
Marc Rondy ◽  
Keyword(s):  
Primary Care ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Influenza A ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Hospital Level ◽  
Case Control Studies ◽  
Care Level ◽  
Primary Care Level

We measured early 2016/17 season influenza vaccine effectiveness (IVE) against influenza A(H3N2) in Europe using multicentre case control studies at primary care and hospital levels. IVE at primary care level was 44.1%, 46.9% and 23.4% among 0–14, 15–64 and ≥ 65 year-olds, and 25.7% in the influenza vaccination target group. At hospital level, IVE was 2.5%, 7.9% and 2.4% among ≥ 65, 65–79 and ≥ 80 year-olds. As in previous seasons, we observed suboptimal IVE against influenza A(H3N2).

scholarly journals Influenza Vaccine Effectiveness and Waning Effect in Hospitalized Older Adults. Valencia Region, Spain, 2018/2019 Season

2021 ◽  
Vol 18 (3) ◽  
pp. 1129
Author(s):  
Ainara Mira-Iglesias ◽  
F. Xavier López-Labrador ◽  
Javier García-Rubio ◽  
Beatriz Mengual-Chuliá ◽  
Miguel Tortajada-Girbés ◽  
...  
Keyword(s):  
Older Adults ◽  
Influenza Vaccine ◽  
Influenza A ◽  
Vaccine Effectiveness ◽  
Surveillance Network ◽  
Adjuvanted Vaccine ◽  
Clinical Registries ◽  
Populations At Risk ◽  
Influenza A H1n1 ◽  
Hospitalized Older Adults

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.

scholarly journals A Call for Caution in Use of Pertussis Vaccine Effectiveness Studies to Estimate Waning Immunity: A Canadian Immunization Research Network Study

2020 ◽  
Author(s):  
Natasha S Crowcroft ◽  
Kevin L Schwartz ◽  
Rachel D Savage ◽  
Cynthia Chen ◽  
Caitlin Johnson ◽  
...  
Keyword(s):  
Study Design ◽  
Case Control ◽  
Vaccine Effectiveness ◽  
Early Years ◽  
Research Network ◽  
Optimal Timing ◽  
Case Control Studies ◽  
Seeking Behavior ◽  
Matched Design ◽  
Duration Of Protection

Abstract Background Vaccine effectiveness (VE) studies provide essential evidence on waning vaccine-derived immunity, a major threat to pertussis control. We evaluated how study design affects estimates by comparing 2 case-control studies conducted in Ontario, Canada. Methods We compared results from a test-negative design (TND) with a frequency-matched design (FMD) case-control study using pertussis cases from 2005–2015. In the first study, we identified test-negative controls from the public health laboratory that diagnosed cases and, in the second, randomly selected controls from patients attending the same physicians that reported cases, frequency matched on age and year. We compared characteristics of cases and controls using standardized differences. Results In both designs, VE estimates for the early years postimmunization were consistent with clinical trials (TND, 84%; FMD, 89% at 1–3 years postvaccination) but diverged as time since last vaccination increased (TND, 41%; FMD, 74% by 8 years postvaccination). Overall, we observed lower VE and faster waning in the TND than the FMD. In the TND but not FMD, controls differed from cases in important confounders, being younger, having more comorbidities, and higher healthcare use. Differences between the controls of each design were greater than differences between cases. TND controls were more likely to be unvaccinated or incompletely vaccinated than FMD controls (P < .001). Conclusions The FMD adjusted better for healthcare-seeking behavior than the TND. Duration of protection from pertussis vaccines is unclear because estimates vary by study design. Caution should be exercised by experts, researchers, and decision makers when evaluating evidence on optimal timing of boosters.

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