Respiratory Syncytial Virus, or RSV, is the most common cause of bronchiolitis and pneumonia in U.S. children under the age of one. While there is no current vaccine, children at high risk for RSV can receive a preventive therapy, consisting of five injections of an antibody to keep the virus at bay during the winter months, when epidemics are common.
A team of researchers led by Daniel Weinberger, assistant professor in the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health, discovered that if timed appropriately to cover a region’s specific RSV season, five doses of the prophylaxis can be reduced to four, saving children a painful jab and, because the therapy can cost thousands of dollars, significant money.
RSV is the leading cause of hospitalization for young children globally. In most cases, the virus causes cold-like symptoms, but for premature infants and children with underlying cardiopulmonary conditions, such as congenital heart defects, the virus can be more dangerous.
In collaboration with two colleagues from the Yale School of Public Health, Virginia Pitzer and Joshua Warren, scientists from the National Institutes of Health and the Agency for Healthcare Research and Quality, the team analyzed hospitalization data from 38 states to evaluate the timing of local RSV epidemics across the United States. Currently the prophylaxis is given according to national guidelines set by the American Academy of Pediatrics, which does not take into account regional variation in the onset of RSV epidemics. Starting the injections too early or too late can leave children unprotected, according to the study. The findings are published in the journal Clinical Infectious Diseases.
The study found that in all states and counties examined, 90 percent to 98 percent of the cases occurring within the optimal 24-week window of protection also occurred during the optimal 20-week window of protection, as determined the typical onset of epidemic in each region. “Like many diseases, RSV epidemics roughly follow a bell-shaped curve,” with most cases of RSV falling in the middle period of the epidemic, said Weinberger. “Protecting children during the middle period of the epidemic is going to be most important, even if the child is protected for a shorter time overall.”
The findings suggest that the prophylaxis would be more effectively implemented using a state-specific recommendation, rather a general national recommendation. The study includes, Weinberger says, recommended start dates for different locations based on available data and statistical analysis. He and his team hope to continue their work to understand the determinants of epidemic timing by examining detailed local hospitalization data from Connecticut, with the goal of informing future recommendations for RSV prophylaxis use nationwide.