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.
We conducted a case-control and screening method studies to estimate influenza vaccine effectiveness (IVE) in the age group >or=65 years, based on the Spanish Influenza Sentinel Surveillance System (SISSS). Cases (influenza laboratory-confirmed) were compared to influenza-negative ILI patients (test-negative) and patients without ILI since the beginning of the season (non-ILI). For the screening method, cases' vaccination coverage was compared to the vaccination coverage of the GPs' catchment population. The results suggested a protective effect of the vaccine against laboratory-confirmed influenza in elderly in 2008-2009. The screening method and the test-negative control designs enable estimating IVE using exclusively SISSS data.
European Centre for Disease Prevention and Control, European Programme for Intervention Epidemiology Training, Stockholm, Sweden. csavulescu@isciii.es
Camelia
C
Savulescu
Marta
M
Valenciano
Salvador
S
de Mateo
Amparo
A
Larrauri
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D035061:Control Groups; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D010865:Pilot Projects; D013030:Spain / Q000453:epidemiology; D016896:Treatment Outcome
D007252:Influenza Vaccines