OBJECTIVE: To evaluate the effectiveness of 1 and 2 doses of the 2003-2004 influenza vaccine in preventing medically attended influenza-like illness (ILI) among children 6 to 23 months and 6 months to 8 years of age. DESIGN AND METHODS: Outpatient and emergency department visits and immunization records were used to conduct a retrospective cohort study among children 6 months to 8 years of age. ILI and pneumonia and influenza (P&I) outcomes were defined on the basis of International Classification of Diseases, Ninth Revision, codes. Influenza vaccine effectiveness (VE) was calculated as (1 - hazard rate ratio) x 100. RESULTS: A total of 29726 children were included in the analyses; 17.3% were 6 to 23 months of age. By November 19, 2003, the start of peak influenza activity, 7.5% and 9.9% of children 6 months to 8 years were fully or partially vaccinated against influenza, respectively. For fully vaccinated children 6 to 23 months of age, VE against ILI and P&I was 25% and 49%, respectively. No statistically significant reduction in ILI or P&I rates was observed for partially vaccinated children 6 to 23 months of age (-3% and 22%, respectively). For fully vaccinated children 6 months to 8 years of age, VE against ILI and P&I was 23% and 51%, respectively. For partial vaccination, VE was significant only for P&I (23%). CONCLUSIONS: Despite a suboptimal match between the influenza vaccine and predominant circulating strains, influenza vaccination provided substantial protection for fully vaccinated children and possibly some protection for partially vaccinated children <9 years of age. These findings support vaccinating targeted children even when the vaccine match is suboptimal, and they highlight the need to vaccinate previously unvaccinated children with 2 doses for optimal protection.
OBJECTIVE: To evaluate the effectiveness of 1 and 2 doses of the 2003-2004 influenza vaccine in preventing medically attended influenza-like illness (ILI) among children 6 to 23 months and 6 months to 8 years of age. DESIGN AND METHODS: Outpatient and emergency department visits and immunization records were used to conduct a retrospective cohort study among children 6 months to 8 years of age. ILI and pneumonia and influenza (P&I) outcomes were defined on the basis of International Classification of Diseases, Ninth Revision, codes. Influenza vaccine effectiveness (VE) was calculated as (1 - hazard rate ratio) x 100. RESULTS: A total of 29726 children were included in the analyses; 17.3% were 6 to 23 months of age. By November 19, 2003, the start of peak influenza activity, 7.5% and 9.9% of children 6 months to 8 years were fully or partially vaccinated against influenza, respectively. For fully vaccinated children 6 to 23 months of age, VE against ILI and P&I was 25% and 49%, respectively. No statistically significant reduction in ILI or P&I rates was observed for partially vaccinated children 6 to 23 months of age (-3% and 22%, respectively). For fully vaccinated children 6 months to 8 years of age, VE against ILI and P&I was 23% and 51%, respectively. For partial vaccination, VE was significant only for P&I (23%). CONCLUSIONS: Despite a suboptimal match between the influenza vaccine and predominant circulating strains, influenza vaccination provided substantial protection for fully vaccinated children and possibly some protection for partially vaccinated children <9 years of age. These findings support vaccinating targeted children even when the vaccine match is suboptimal, and they highlight the need to vaccinate previously unvaccinated children with 2 doses for optimal protection.
Authors: Behzad Yeganeh; Saeid Ghavami; Andrea L Kroeker; Thomas H Mahood; Gerald L Stelmack; Thomas Klonisch; Kevin M Coombs; Andrew J Halayko Journal: Am J Physiol Lung Cell Mol Physiol Date: 2014-10-31 Impact factor: 5.464
Authors: Rogier Bodewes; Pieter L A Fraaij; Martina M Geelhoed-Mieras; Carel A van Baalen; Harm A W M Tiddens; Annemarie M C van Rossum; Fiona R van der Klis; Ron A M Fouchier; Albert D M E Osterhaus; Guus F Rimmelzwaan Journal: J Virol Date: 2011-08-31 Impact factor: 5.103
Authors: Justin R Ortiz; Kathleen M Neuzil; John C Victor; Anna Wald; Moira L Aitken; Christopher H Goss Journal: Chest Date: 2009-12-04 Impact factor: 9.410
Authors: Rogier Bodewes; Joost H C M Kreijtz; Chantal Baas; Martina M Geelhoed-Mieras; Gerrie de Mutsert; Geert van Amerongen; Judith M A van den Brand; Ron A M Fouchier; Albert D M E Osterhaus; Guus F Rimmelzwaan Journal: PLoS One Date: 2009-05-14 Impact factor: 3.240