Effectiveness of virosomal subunit influenza vaccine in preventing influenza-related illnesses and its social and economic consequences in children aged 3–14 years: A prospective cohort study

• Published in: Vaccine Vol. 24; no. 44; pp. 6638 - 6642
• Main Authors: Salleras, L., Domínguez, A., Pumarola, T., Prat, A., Marcos, M.A., Garrido, P., Artigas, R., Bau, A., Brotons, J., Bruna, X., Català, P., Carreras, E., Cuadra, D., Gatell, A., Millet, S., Oller, J., Raga, E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 10.11.2006; Elsevier; Elsevier Limited
• Subjects: Absenteeism; Adolescent; Antibiotics; Applied microbiology; Biological and medical sciences; Child; Child, Preschool; Children; Cohort Studies; Confidence intervals; Drug Delivery Systems; Economics; Effectiveness; Families & family life; Fundamental and applied biological sciences. Psychology; Hepatitis; Humans; Immunization; Influenza; Influenza Vaccines - administration & dosage; Influenza Vaccines - adverse effects; Influenza Vaccines - economics; Influenza Vaccines - immunology; Influenza, Human - epidemiology; Influenza, Human - prevention & control; Laboratories; Metropolitan areas; Microbiology; Parents & parenting; Pediatrics; Prospective Studies; Respiratory diseases; Vaccines; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - adverse effects; Vaccines, Inactivated - immunology; Vaccines, Subunit - adverse effects; Vaccines, Subunit - immunology; Vaccines, Virosome - administration & dosage; Vaccines, Virosome - adverse effects; Vaccines, Virosome - immunology; Virosome; Spain, Cataluna, Barcelona; Virosome; Effectiveness; Vaccines; Children; Influenza; Human; Infection; Viral disease; Cohort study; Vaccine; Subunit; Child
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2006.05.034

To evaluate the effectiveness of a virosomal subunit influenza vaccine in preventing influenza-related illnesses and its social and economic consequences in children aged 3–14 years, a prospective cohort study was carried out during the 2004–2005 influenza season in 11 private pediatric clinics in the Barcelona metropolitan area. One dose of a virosomal subunit inactivated influenza vaccine (Inflexal V ® Berna) was given during September and October 2004 to healthy children aged 3–14 years attended in 5 of the 11 clinics. Who comprised the vaccinated cohort ( n = 966). The non-vaccinated cohort ( n = 985) was comprised of children attended in the other six clinics. Informed consent was obtained from all parents. The follow up was performed between 1 November 2004 and 31 March 2005. Using a self-administered questionnaire, information was collected from parents or guardians on any type of acute, febrile respiratory illness suffered by their children during the study period, including antibiotic use, and absence from school or work-loss of parents as a result of the illness. RT-PCR (influenza A + B + C) was carried out on pharyngeal and nasal samples obtained from children attended by pediatricians during this period in these clinics with the following symptoms: fever ≥ 38.5° lasting at least 72 h, cough or sore throat (influenza-like illness). Adjusted vaccination effectiveness was 58.6% (95% CI 49.2–66.3) in preventing acute febrile respiratory illnesses, 75.1% (95% CI 61.0–84.1) in preventing cases of influenza-like illnesses and 88.4% (95% CI 49.2–97.3) in preventing laboratory-confirmed cases of influenza A. The adjusted vaccination effectiveness in reducing antibiotic use (18.6%, 95% CI −4.2 to 3.64), absence from school (57.8%, 95% CI 47.9–65.9) and work-loss of parents (33.3%, 95% CI 8.9–51.2) in children affected by an acute febrile respiratory illness was somewhat lower. Vaccination of children aged 3–14 years in pediatric practices with one dose of virosomal subunit inactivated influenza vaccine has the potential to considerably reduce the health and social burdens caused by influenza-related illnesses.