Immune response to influenza vaccination in children and adults with asthma: effect of corticosteroid therapy.

BACKGROUND: Annual influenza vaccination is currently recommended as a preventative measure for all patients with asthma. However, the effect of maintenance corticosteroid therapy on the immune response to influenza vaccine has received limited evaluation. OBJECTIVE: In this study, we evaluated the effect of corticosteroid therapy on the immune response to influenza vaccine in children and adults with asthma. METHODS: This was a substudy of a larger multicenter, randomized, double-masked, placebo-controlled, crossover study investigating the safety of trivalent influenza vaccine in patients with asthma. At baseline, 294 subjects were randomized to receive either placebo first (n=139) or inactivated trivalent split-virus influenza vaccine first (n=155). Study subjects were categorized into 2 groups: subjects in group 1 (n=148) were receiving medium-dose or high-dose inhaled corticosteroids (ICSs) or oral corticosteroids, whereas subjects in group 2 (n=146) were not receiving corticosteroids or were receiving low-dose ICSs. Serum hemagglutination inhibition antibody titers for the vaccine antigens were measured before and 4 weeks after the administration of placebo or vaccine. RESULTS: Serologic responses to each influenza vaccine antigen were significantly higher in vaccine than in placebo recipients and were similar among influenza vaccine recipients in groups 1 and 2 for the following endpoints: rise in antibody titer, percent of participants who developed a serological response, and percent of subjects who developed a serum hemagglutination inhibition antibody titer > or =1:32. Post hoc subgroup analyses demonstrated an attenuated response to influenza B antigen in subjects receiving high-dose ICS compared with subjects who were steroid-naïve (P<.05). CONCLUSION: The immune response to the A antigens of the inactivated influenza vaccine in subjects with asthma is not adversely affected by ICS therapy. High-dose ICS therapy may diminish the response to the B antigen of the vaccine, an observation that needs further investigation.