Researchers from the Yale School of Public Health shed new light on the factors that induced seasonal variations for Pneumococcal bacteria provided information that will help to understand and predict the impacts of vaccination. The study entitled “Reduced-dose schedule of prophylaxis based on local data provides near-optimal protection against RSV” was published in the Clinical Infectious Diseases by Daniel Weinberger from the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health along with colleagues.
Respiratory Syncytial Virus (RSV) is a virus that causes respiratory tract infections and is the most frequent cause of bronchiolitis and pneumonia in children younger than one year old in the United States. Although there is no currently any vaccine available, the standard preventive treatment consists of 5 injections of an antibody to keep the virus controlled during the winter period, when epidemics are frequent. Worldwide, this infection is the main cause of hospitalization for young children. In temperate climates, the infection peaks during the winter months while in tropical climates occurs mostly during the rainy season.
The research team proposed that a reduced-dose plan tailored to the local RSV season in the continental United States would give suitable protection. They analyzed data stored in the State Inpatient Databases between 1997 and 2009. They evaluated the fraction of RSV cases that occurred during the protection period of time given by the RSV prophylaxis over different weeks of the year.
The researcher found that the timing of RSV epidemic onset changed considerably at the local level. However, the national guidelines for prophylaxis initiation gave almost optimal protection of the RSV season in the majority of locations across United States. They observed that the reduction from 5 to 4 doses per month (with a later initiation) provided almost optimal coverage, with a decrease in coverage lower than 5%, in most locations. The initiation of 4-doses of prophylaxis was associated with places located at south and east, higher population density and with higher percentage of black or Hispanic population.
Overall, the 4 dose plan of prophylactic injections timed with the local RSV epidemics could give protection similar to 5 doses and may be seen as a strategy to ameliorate the cost effectiveness of prophylaxis.