Informing randomized clinical trials of respiratory syncytial virus vaccination during pregnancy to prevent recurrent childhood wheezing: A sample size analysis.
Early Respiratory Syncytial Virus (RSV) illness is associated with wheeze-associated disorders in childhood. Candidate respiratory syncytial virus (RSV) vaccines may prevent acute RSV illness in infants. We investigated the feasibility of maternal RSV vaccine trials to demonstrate reductions in recurrent childhood wheezing in general pediatric populations.
Vaccination of pregnant women against RSV may protect their infants against RSV illness during their first months of life, primarily through maternal antibodies transported across the placenta. While licensure of RSV vaccines for use during pregnancy is likely to be sought for the primary indication of preventing acute RSV illness in young infants, the public health value of maternal RSV vaccines would be greater if the vaccine also prevented wheeze-associated disorders. Studies to assess the effects of RSV prevention on these childhood respiratory outcomes have been recommended by experts convened by the Bill & Melinda Gates Foundation, the Lancet, and the World Health Organization (WHO). However, the sample sizes required to detect an effect on such outcomes in randomized clinical trials (RCTs) have not been calculated.