INFLUENZA VACCINATION OF CHILDREN DURING ACUTE ASTHMA EXACERBATION AND CONCURRENT PREDNISONE THERAPY

Objectives. The influenza vaccination rate is very low among children with moderate to severe asthma. This may be partly because of poor pat ient motivation and failure to visit clinics for vaccination. Another important factor may be health care providers' deferral of vaccination because of concern about the efficacy and safety of influenza vaccina tion during asthma exacerbations and concurrent prednisone therapy. We therefore examined the safety and immunogenicity of influenza vaccina tion during acute asthma exacerbation with concomitant prednisone ther apy. Setting. A pediatric allergy and pulmonology clinic and a pediatr ic emergency department. Design. Children (n = 109) with a known diagn osis of asthma 6 months to 18 years of age were recruited. All partici pating patients, 59 without asthma symptoms (no prednisone, control gr oup) and 50 with acute asthma exacerbation requiring prednisone burst therapy (prednisone group) received trivalent subvirion influenza vacc ine. Fifteen children in the control group and 12 in the prednisone gr oup received a booster dose according to American Academy of Pediatric s guidelines. Serum antibody titers to influenza A/Beijing/32/92 (H3N2 ), influenza A/Texas/36/91 (H1N1), and influenza B/Panama/45/90 were m easured before and 2 weeks after vaccination. Adverse effects noted wi thin 48 hours after vaccine dose were ascertained during the follow-up visit. Results. The antibody response was analyzed by comparing mean postvaccine titers, the percentage of patients achieving protective an tibody levels (greater than or equal to 5log(2)), and the percentage o f patients achieving rises in titers of 2log(2) or greater. Antibody r esponses to influenza A/Beijing/32/92 (H3N2) and influenza A/Texas/36/ 91 (H1N1) in the prednisone-treated and control groups were not differ ent. A significantly better response to the influenza B/Panama/45/90 a ntigen was seen in the prednisone group for all three parameters. Chil dren who received a booster dose and the subgroup of children with low prevaccination titers (less than or equal to 3log(2)) showed similar patterns. Adverse effects, including asthma exacerbation, local swelli ng at the injection site, fever, rash, and headache, were not differen t in the two groups. Conclusions. Influenza vaccination can be given s afely and effectively to asthmatic children regardless of asthma sympt oms or concurrent prednisone therapy when necessary. Vaccination of al l moderate to severe asthmatic patients visiting clinics or emergency departments would improve the overall vaccination rate significantly.