Rotavirus (RV) infection is the leading cause of diarrheal disease in young children worldwide, causing more than half a million deaths of children aged <5 years annually, according to the World Health Organization. There are two safe and effective RV vaccines, pentavalent Rotateq (Merck) and monovalent Rotarix (GSK), yet global coverage remains below 20% of children.
According to the U.S. immunization schedule, infants should receive two (Rotarix) or three (Rotateq) doses between the ages of 6 weeks and 8 months. However, a study published in Human Vaccines & Immunotherapeutics suggests that 40% of U.S. infants from low-income families do not receive even a single dose of RV vaccine.
A team of scientists from GSK Vaccines and Analysis Group studied completion (an infant receives all doses within the overall recommended timeframe) and compliance (an infant receives each dose during the recommended time interval) rates in four states—Florida, Iowa, Arkansas, Mississippi—by analyzing Medicaid administrative claims data for >650,000 infants during the period 2008-13. Medicaid is a U.S. public health insurance program for the low-income population, which covered almost 30 million children in 2013.
The results show that of those infants who received the first dose of either Rotarix or Rotateq, less than 60% and 50%, respectively, completed the entire series. The numbers were slightly lower for compliance rates.
“The results may depend on patient population characteristics, such as parent education level and socioeconomic status,” says senior author Songkai Yan, Director of US Health Outcomes & Epidemiology at GSK. “The study showed lower RV vaccination rates, and lower compliance and completion rates compared with studies evaluating commercially insured infants.”
“One reason for the low rate of RV vaccination may be that infants with Medicaid coverage are less likely to have a regular healthcare provider and their parents are less likely to have transportation to the doctor’s office.”
Another big potential factor that may contribute to the sizeable rate of non-vaccination, even in privately insured infants, is that RV disease might not be viewed by parents as being as serious as other infectious diseases and RV vaccination usually is not required by school systems.
The rates differed across states: the proportion of unvaccinated infants ranged from 50% in Florida to 22% in Mississippi. Both completion and compliance were consistently higher for the two-dose Rotarix than the three-dose Rotateq.
“A simple, convenient dosing regimen of a vaccine can lead to better compliance and completion of vaccination. For a disease such as RV that is viewed as being less serious than other infectious diseases, more efforts may be needed in educating the public to increase awareness in order to achieve optimal immunization goals,” concludes Songkai Yan.