Department of Biostatistics Seminar/Workshop Series

Effectiveness of RSV immunoprophylaxis on RSV induced morbidity in high-risk infants

Pingsheng Wu, PhD, MS

Research Assistant Professor of Medicine & Biostatistics, Department of Medicine, Vanderbilt University School of Medicine

Wednesday, April 11, 1:30-2:30pm, MRBIII Room 1220

Respiratory syncytial virus (RSV) is the leading cause of serious upper and lower respiratory tract infection in infants and children, causing significant morbidity and mortality worldwide in children under age 5 years.  The initial RSV infection is typically the most severe, causing lower respiratory tract disease, such as bronchiolitis, in 20% to 30% of infants.  Currently, RSV immunoprophylaxis is the only available preventive approach, licensed for use in prophylaxis for RSV-attributable morbidity in high-risk infants.  While there have been a number of randomized clinical trials of RSV immunoprophylaxis to establish the “efficacy” in decreasing infant RSV morbidity and mortality, the comparative effectiveness of RSV immunoprophylaxis has not been studied. The objectives of this study were to determine the real world effectiveness of RSV immunoprophylaxis, hypothesizing that the real world effectiveness would be lower than efficacy trials on a measurable reduction in RSV-attributable healthcare visits. To test our hypothesis, we conducted a retrospective cohort study of infants who were born from 1996 to 2008 and were continuously enrolled in an insured health care organization. The effectiveness of RSV immunoprophylaxis on bronchiolitis healthcare visits during the RSV season (November to March) was determined. RSV immunoprophylaxis was associated with an average of 40% decrease in RSV hospitalization rate, but did not decrease rate of less severe RSV healthcare visits. RSV immunoprophylaxis was most effective in reducing RSV-related morbidity in children with chronic lung disease with an effect size that was comparable to that seen in efficacy (RCT) trials.