S.P.65 Immunogenicity of intramuscular versus subcutaneous administration of Trivalent Inactivated Influenza Vaccine (TIV) in individuals with neuromuscular diseases

Abstract

Abstract TIV is recommended for patients with late stage muscular dystrophy/atrophy. However, their immune response to the standard intramuscular (IM) route versus a subcutaneous (SC) route has not been studied. Objective: To compare immunogenicity and safety of TIV administered IM vs. SC and (2) To assess immune responses to TIV in subjects receiving glucocorticoids. Study design: A prospective, randomized, open-label study. Serum hemagglutination inhibition (HAI) antibody titers before and ⩾21 days after vaccine administration. Geometric mean titer (GMT) ratios against the three influenza antigen strains were compared for both routes. Seroprotection (SPN) against each strain was defined as HAI titer of ⩾1:40. Seroconversion (SCN) was defined as post-vaccination titer of ⩾1:40 for those with baseline titer of 0.5) between IM and SC routes. SCN for the IM vs. SC route was 45% vs. 55% for H1N1; 9% vs. 18% for H3N2; and 45% vs. 9% for B. For subjects receiving glucocorticoids (n = 10), baseline SPN rates were 100% for H1N1, 70% for H3N2, and 50% for B and rose to 100% for H1N1, 80% for H3N2, and 60% for B post-vaccination. TIV was well tolerated. The immediate pain score (visual analogue scale) was higher for the IM route; p = 0.013. Non-ambulatory subjects with late stage muscular dystrophy/atrophy had similar immune responses to IM vs. SC administration of TIV. SPN was not adversely affected by glucocorticoid therapy. Local tolerance was better with SC route.