Effectiveness of influenza vaccination in prevention of influenza-like illness among inhabitants of old folk homes.
The aims of the study were to determine the attack rate of influenza-like illness among inhabitants of five old folk homes nationwide using influenza vaccine as a probe and the effectiveness of influenza vaccination in prevention of influenza-like illness. We conducted a nonrandomized, single-blind placebo control study from June 2003 to February 2004. VAXIGRIP(R) 2003 Southern hemisphere formulation was used. Among 527 subjects, the attack rates of influenza-like illness in the influenza vaccine group were 6.4, 4.6 and 2.4% during the first, second and third 2-month periods, respectively. The attack rates of influenza-like illness in the placebo group were 17.7, 13.8 and 10.1%. Influenza vaccination reduced the risk of contracting influenza-like illness by between 14, and 45%. The vaccine effectiveness in reducing the occurrence of influenza-like illness ranged from 55 to 76%, during the 6-month study followup. The presence of cerebrovascular diseases significantly increased the risk of influenza-like illness (p < 0.005). Vaccine recipients had fewer episodes of fever, cough, muscle aches, runny nose (p < 0.001) and experience fewer sick days due to respiratory illness. Subjects who received influenza vaccination had clinically and statistically significant reductions in the attack rate of influenza-like illness. Our data support influenza vaccination of persons with chronic diseases and >50 year olds living in institutions.
Isahak
Ilina
I
Department of Medical Microbiology and Immunology, Faculty of Medicine, University Kebangsaan Malaysia, Kuala Lumpur. ilina@mail.hukm.ukm.my
Mahayiddin
Aziah Ahmad
AA
Ismail
Raman
R
D000368:Aged; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D009981:Influenza B virus / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008296:Malaysia / Q000453:epidemiology; D008297:Male; D009735:Nursing Homes / Q000706:statistics & numerical data*; D011446:Prospective Studies; D016037:Single-Blind Method
D007252:Influenza Vaccines