Comparison of the Immunogenicity of Intramuscular Versus Subcutaneous Administration of Trivalent Inactivated Influenza Vaccine in Individuals With Neuromuscular Diseases

Individuals with neuromuscular diseases are more prone to influenza-related morbidity. Vaccination is the most effective measure to reduce the influenza disease burden. In the United States, the recommended route of administration for the inactivated influenza vaccine is intramuscular. In other countries, the subcutaneous, deep subcutaneous, and intramuscular routes are all considered acceptable for influenza vaccine administration. The United States CDC states that subcutaneous influenza vaccine doses, provided they are age-appropriate, may be counted as valid.

Those with neuromuscular diseases have muscle fibrosis that may potentially make intramuscular vaccines more effective. Those with Duchenne muscular dystrophy receive systemic corticosteroids to reduce inflammation. Corticosteroids may suppress antibody responses to vaccines. The goal of this research study is to evaluate the immunogenicity and safety of intramuscular and subcutaneous administration of inactivated influenza vaccine in individuals with neuromuscular diseases. This is a single site, open-label, randomized study. At the first visit, a blood sample was collected prior to vaccination. Each subject received either an intramuscular or subcutaneous vaccine administered in the anterolateral aspect of the thigh. Within 30 minutes of vaccination, subjects rated pain at the injection site using a numeric pain scale (0-10). Subjects and their caregivers were also asked to record local and systemic adverse events on diary sheets from day 0 to day 4 after vaccination. Subjects were instructed to notify the study staff by telephone should they develop any serious adverse reactions following vaccination. At a second study visit approximately 28 days later, a repeat blood sample was obtained. The blood samples obtained pre-vaccination and also at day 28 were tested for hemagglutination inhibition (HI) titers to the three influenza vaccine strains. rovider's office. The geometric mean titer ratios for each of the three vaccine strains were calculated as the ratios of postvaccination to prevaccination titers at geometric mean scale.