Vaccine effectiveness in preventing influenza hospitalizations in Navarre, Spain, 2010–2011: Cohort and case–control study

Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review

“…The majority of studies made VE estimates for patients of all ages (n=48; one excluded children <10y [85]), with the remainder targeted at adults (≥15y; n=12; 2 restricted to adults ≥50y [27, 87]), children (n=9 [19, 26, 29, 31, 47, 59, 62, 81, 94]), elderly (n=4 [51, 53, 72, 95]), children and adults aged 50+ (n=1 [84]), pregnant women (n=1 [89]), military (n=2 [28, 40]), healthcare workers (n=1 [42]) or people at high-risk or in a target group for vaccination (n=7 [14, 18, 20, 25, 43, 44, 52]).…”

“…This variable was described as month (n=21), week (n=24) or some other “period” relative to the start [87] or peak of the season (n=3 [27, 31, 91]) or variously defined (n=10 [16, 20–22, 31, 39, 40, 48, 58, 89]). It was often unclear whether the variable was specified as a categorical or linear term.…”

“…inpatient/outpatient, long-term care, n=5 [21, 22, 58, 91, 95]), interval between disease onset and swab (linear term or categorised, n=12), previous vaccination (e.g. seasonal & monovalent or multiple seasonal, n=14), receipt of the pneumococcal vaccine (n=2 [20, 72]), antiviral treatment (n=1 [56]), race/ethnicity (n=8 [19, 42, 47, 97, 87–90]), insurance status (n=4 [29, 37, 81, 90]), socioeconomic status (n=5 [42, 53, 56, 57, 91]), number of children in the household (n=1 [20]), whether or not the illness was medical (n=1 [89]), overseas travel (n=1 [42]), enrolment outside active recruitment (n=1 [31]), and preterm birth (n=2 [19, 47]). Only one study explored any interactions, namely the product of vaccination history and military camp [40].…”

Case-Control Study of the Effectiveness of the 2010-2011 Seasonal Influenza Vaccine for Prevention of Laboratory-Confirmed Influenza Virus Infection in the Korean Adult Population

“…Although the influenza vaccine was not found to be effective in older adults in this study, the influenza vaccine could reduce influenza-associated morbidity and mortality in that population. A study performed in Spain reported that the 2010-2011 influenza vaccine had a moderate effect in preventing hospitalization in the at-risk population (17). Third, we did not check the A/H1N1 2009pdm virus vaccination or infection history.…”

Use of the vaccination register to evaluate influenza vaccine coverage in seniors in the 2010/11 influenza season, Navarre, Spain

“…In Navarre, the vaccine register is used primarily so that physicians and nurses can consult the vaccine status of their patients at any time and to programme the dates to administer the doses of the vaccine schedule. This register allows more rigorous research, because it contains individual-level information that can be used to conduct population-based studies to measure the impact of vaccination programmes, to evaluate vaccine effectiveness, and to monitor vaccine safety [13][14][15][16][17][18][19][20][21].…”