Controversy exists regarding the effectiveness of influenza vaccination in preventing influenza-related asthma exacerbations in the pediatric population. While yearly influenza immunization is widely recommended for asthmatic children, there is currently little evidence to support this practice. Several studies have demonstrated no measurable benefit in asthma outcomes. This study sought to determine if influenza vaccination status is associated with indicators of asthma morbidity within the military pediatric population.
A survey of patients aged 3-18 years with a diagnosis of asthma enrolled to the pediatric clinics of Brooke Army Medical Center, Fort Sam Houston, Texas and Wilford Hall Medical Center, Lackland Air Force Base, Texas was conducted. Management practices and outcomes for 80 children were evaluated. Univariate analyses were performed to identify associations between influenza vaccination and selected demographic variables and asthma exacerbation defined by oral steroid prescription, hospital visits and unscheduled clinic or emergency department visits for asthma symptoms. Logistic regression analyses were conducted to detect possible confounding variables.
In the univariate analyses, current influenza vaccination status was associated with a significant reduction of oral steroid use in the 12 months prior to the survey (Table 1). This relationship was appreciated to a lesser extent with ED or unscheduled clinic visits in last 12 months. No significant differences were found regarding the distribution of influenza vaccination status across selected variables. In the multivariate analyses, current influenza vaccination status was independently associated with significantly decreased odds of using oral steroids in the previous 12 months (Table 2). There was no evidence of confounding or effect modification.
This study suggests influenza vaccination is associated with fewer asthma exacerbations. After controlling for several potential confounding variables, administration of influenza vaccine was associated with a protective effect against indicators of asthma exacerbations. Our results indicate that pediatric asthmatics in the military beneficiary population may benefit from annual influenza vaccination.
These measurable differences in asthma outcomes help confirm current recommendations for clinical practice and set the stage for further prospective trials.
Univariate Analysis, Distribution of Influenza Vaccination Status Pilot Data, N = 80Independent variableReceived vaccination (n = 49) Number (%)No vaccination (n = 31) Number (%)Chi Square p ValueRaceWhite26 (53)9 (29)0.97Non-White13 (26)22 (70)GenderMale24 (49)20 (65)0.62Female25 (51)11 (35)Has asthma action plan33 (67)13 (42).025Received formal asthma education32 (65)16 (68).0.22On post housing13 (27)5 (16)0.99Prescribed oral steroid32 (65)15 (48)0.03Hospitalized in last 12 months7 (14)5 (16)0.68Unscheduled ED or clinic visit last 12 months31 (63)15 (48)0.59Prescribed ICS42 (86)27 (87)0.25Active duty family member34 (69)20 (65)0.35Table 2—
Logistic Regression of Asthma Outcomes by Influenza Vaccination Status and Covariates, Pilot Data, N = 80Independent variableOdds of prescribed oral steroid OR (95% CI)Odds of being hospitalized in last 12 months OR (95% CI)Odds of ED or unscheduled clinic visit in last 12 months OR (95% CI)RaceAA1.16 (0.37-3.60)3.73(0.66-21.08)1.07 (0.34-3.37)MA1.99 (0.60-6.63)2.01 (0.32-12.70)0.72 (0.23-2.25)Gender, male1.70 (0.60-4.84)0.48 (0.12-1.94)2.41(0.86-6.78)Received influenza vaccine in last 12 months0.290(0.10-0.84)1.39 (0.34-5.67)0.54 (0.20-1.49)On post housing1.56 (0.49-5.02)0.59(0.11-3.10)1.61 (0.52-5.02)Prescribed ICS2.15(0.48-9.61)1.48 (0.15-15.10)2.55 (0.58-11.30)
Bruce Ong, None.