In children, the most common side effects following the first dose of vaccine included headache, runny/stuffy nose, and cough. In adults, the most common side effects were headache, runny nose and decreased activity. Symptoms after the second dose were similar but generally occurred at lower rates in both children and adults. No vaccine-related serious adverse events have been reported in children or adults. The local and systemic symptoms observed are consistent with intranasal vaccine virus replication and are similar to those observed with seasonal LAIV. Serum antibody responses to the vaccine in addition to pre-clinical characterization data are also consistent with previously studied formulations of seasonal LAIV, which has been shown in multiple studies to be safe and effective in eligible children and adults 2 to 49 years of age.

LAIV initiates the immune response in the nose, where the virus enters the body and replicates, and is the key to establishing a vaccine response that will help prevent disease if the person later encounters a circulating H1N1 virus. In response to the vaccine, the body develops mucosal immunoglobulin A (IgA), serum immunoglobulin G (IgG), and cellular immunity to help protect the individual from infection from an influenza virus.

Study results have been submitted to and reviewed by authorities at the FDA, the U.S. Centers for Disease Control and Prevention (CDC), the National Institutes of Health (NIH), and the U.S. Department of Health and Human Services (HHS).

SOURCE MedImmune