School-based influenza vaccination program reduces influenza-related outcomes among household members
Article Outline
- King JC, Stoddard JJ, Gaglani MJ, Moore KA, Magder L, McClure E, et al. Effectiveness of school-based influenza vaccination. N Engl J Med 2006:355:2523-32
- References
- Copyright
King JC, Stoddard JJ, Gaglani MJ, Moore KA, Magder L, McClure E, et al. Effectiveness of school-based influenza vaccination. N Engl J Med 2006:355:2523-32
Question How effective is a school-based influenza vaccination program at decreasing the incidence of influenza-like illness?
Design Prospective study of households of elementary school students.
Setting Demographically similar clusters of elementary schools in four states.
Participants 11 clusters of schools. Intervention schools were assigned to participate in a vaccination program. 1-2 control schools were selected for each cluster.
Intervention During a predicted week of peak influenza activity in each state, all households with children in intervention and control schools were surveyed.
Outcomes Influenza vaccination rates and outcomes of influenza-like illness during the previous 7 days.
Main Results In all, 47% of students in intervention schools received live attenuated influenza vaccine (LAIV). As compared with control-school households, intervention-school households reported significantly fewer influenza-like symptoms and office visits during the recall week; rates of emergency department use did not vary between the two groups. Paradoxically, intervention-school households (both children and adults) had higher rates of hospitalization per 100 persons than did control-school households. However, there was no difference in the overall hospitalization rates for children or adults in households with vaccinated children, as compared with those with unvaccinated children, regardless of study-group assignment. Rates of school absenteeism for any cause (based on school records) were not significantly different between intervention and control schools.
Conclusions Most outcomes related to influenza-like illness were significantly lower in intervention school households than in control-school households.
Commentary Influenza vaccination rates among children have historically been low,1 especially among children with high-risk conditions.2, 3 King, et al illustrate the potential of a population-based program to reduce the burden of influenza-like illness among elementary school children; they do so through an influenza vaccination intervention focused solely on healthy children. Although the findings presented are encouraging, there are several important aspects to bear in mind while interpreting these results. This intervention was restricted to administration of FluMist (MedImmune) live attenuated influenza vaccine (LAIV). Since children with underlying medical conditions such as a chronic disease are not eligible for LAIV, they were excluded from receiving influenza vaccine through the intervention.4 Additionally, this study did not assess the reasons why children chose not to be vaccinated through the school-based program, nor does it control for the degree to which students may have been vaccinated in other settings. These aspects of the study design confound interpretation of the findings presented, such as increased absenteeism among unvaccinated students – a group that presumably includes the entirety of the student population with underlying medical conditions. As a consequence, one cannot determine which characteristics of schools prior to the intervention were associated with the greatest incremental improvements in influenza-related outcomes. In addition, the influenza-like illness outcomes assessed by King et al are based on self-reported data from households, the accuracy of which may be questionable. While the analysis presented does provide an understanding of the overall effect of a school-based LAIV program, it falls short of illustrating the full potential that might be realized by a more comprehensive school-based effort that also includes the option of trivalent inactivated influenza vaccine (TIV). This is an important consideration given the prevalence of chronic conditions among children and the relative expense of LAIV, which is not covered by many insurance programs.
References
- . Estimated influenza vaccination coverage among adults and children -- United States, September, 1 2004 - January 31, 2005. MMWR Morb Mortal Wkly Rep. 2005;54:304–307
- Missed opportunities for influenza vaccination in children with chronic medical conditions. Arch Pediatr Adolesc Med. 2005;159:986–991
- . Effect of missed opportunities on influenza vaccination rates among children with asthma. Arch Pediatr Adolesc Med. 2006;160:966–971
- . Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report. 2006;55:1–42
PII: S0022-3476(07)00370-8
doi:10.1016/j.jpeds.2007.04.021
© 2007 Mosby, Inc. All rights reserved.
