Original ArticlesDoes influenza vaccination prevent asthma exacerbations in children?*
Section snippets
Methods
We conducted a retrospective cohort study with the Vaccine Safety Datalink, a computerized, linked database on immunizations, medical encounters, and demographic information.13 VSD contains data on more than 1,000,000 children enrolled in 4 large health maintenance organizations located on the West Coast of the United States. We analyzed 3 consecutive influenza seasons (October 1 through April 30) between 1993 and 1996. At the time of our analysis, data were available from 3 HMOs for the
Results
Depending on the influenza season, between 22,231 and 70,753 children with asthma were included in the analysis (Table I).Empty Cell Influenza season 1993-1994* 1994-1995* 1995-1996† No. of children with asthma 22,231 38,669 70,753 Sex Female, n (%) 9,235 (41.5) 16,115 (41.7) 29,908 (42.3) Male, n (%) 12,996 (58.5) 22,554 (58.3) 40,845 (57.7) Age (y) 1-2, n (%) 6,845 (30.8) 11,112 (28.7) 18,712 (26.5) 3-4, n (%) 7,982 (35.9) 14,419 (37.3) 26,200
Discussion
We found that the apparent effectiveness of influenza vaccination against asthma exacerbations is highly confounded by asthma severity. In the traditional cohort analysis, in which vaccinated children were compared with unvaccinated children, we found that vaccination was associated with an increased risk of asthma exacerbations. Adjusting the cohort analysis for measures of asthma severity and other potential confounders decreased the relative risks, but risks remained significantly elevated.
Acknowledgements
Members of the Vaccine Safety Datalink Team:
Frank DeStefano MD, MPH, Robert T. Chen, MD, MA, John Glasser, PhD, MPH, Philip H. Rhodes, PhD, Steven Wassilak, MD, Piotr Kramarz, MD, Thomas Verstraeten, MD, Emmett Swint, MA, David Walker, MPH, Catherine Okoro, MS, Paul Gargiullo, PhD, Drew Baughman, MS, David King (National Immunization Program, Centers for Disease Control and Prevention, Atlanta, Georgia); Robert S. Thompson, MD, MPH, Robert L. Davis, MD, Lisa A. Jackson, MD, MPH, Patti Benson,
References (28)
- et al.
Greater frequency of viral respiratory infections in asthmatic children as compared with their nonasthmatic siblings
J Pediatr
(1974) - et al.
Immunization with killed influenza virus in children with chronic asthma
Chest
(1978) - et al.
Randomised placebo-controlled crossover trial on effect of inactivated influenza vaccine on pulmonary function in asthma
Lancet.
(1998) - et al.
Use of an automated prescription database to identify individuals with asthma
J Clin Epidemiol
(1995) - et al.
Influenza vaccination in children with asthma in Health Maintenance Organizations
Vaccine
(2000) - et al.
The economic burden of asthma in US children: estimates from the National Medical Expenditure Survey
J Allergy Clin Immunol
(1999) - et al.
Sense and nonsense of influenza vaccination in asthma and chronic obstructive pulmonary disease
Am J Respir Crit Care Med
(1995) - et al.
The relationship between upper respiratory infections and hospital admissions for asthma: a time-trend analysis
Am J Resp Crit Care Med
(1996) Serious morbidity and mortality associated with influenza epidemics
Epidemiol Rev
(1982)Prevention and Control of Influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP)
MMWR
(1997)
Guidelines for the diagnosis and management of asthma
Influenza
Improving influenza vaccination rates in children with asthma: a test of a computerized reminder system and an analysis of factors predicting vaccination compliance
Pediatrics
Does influenza vaccination exacerbate asthma? Analysis of a large cohort of children with asthma. Vaccine Safety Datalink
Arch Fam Med
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Reprint requests: Frank DeStefano, MD, MPH, National Immunization Program, Centers for Disease Control and Prevention, 1600 Clifton Rd, MS-E61, Atlanta, GA 30333.