Minor vaccine hesitancy creates three-fold increase in measles outbreaks
Slight reductions in measles-mumps-rubella vaccinations resulting from vaccine hesitancy have the ability to create a three-fold increase in measles cases, according to a study published in JAMA Pediatrics.
“In [some areas in the United States], there is growing vaccine hesitancy that could accelerate gaps in vaccine coverage across the United States.,” Nathan C. Lo, BS, from the division of epidemiology at Stanford University, and Peter J. Hotez, MD, PhD, from the Texas Children’s Hospital Center for Vaccine Development and the National School for Tropical Medicine at Baylor University, wrote.
“The determinants of the parental decision-making process on whether to vaccinate their child are complex and context specific, but are often influenced by misinformation, false claims regarding safety, and a low perceived risk of infectious diseases among other factors,” they continued.
To evaluate the impact of vaccine hesitancy on the number of measles cases in U.S., as well as the economic cost of such hesitancy, the researchers conducted a simulation in which county MMR vaccination coverage was assessed in children between 2 and 11 years.
Data was gathered from the U.S. CDC, and a mathematical model was modified to estimate infectious disease transmission. Through this approach, outbreak sizes were compared with vaccine coverage. All information regarding economic costs was collected from literature. The researchers then estimated the predicted effects of increased vaccine hesitancy and the removal of nonmedical exemptions.
When MMR coverage decreased by 5%, the researcher observed an annual three-fold increase in measles cases in children between 2 and 11 nationally. This would also result in a $2.1 million increase in public sector costs. When unvaccinated infants, children and adults were included, this increase would be substantially greater.
“Presently, 18 states allow for nonmedical personal belief exemptions to childhood vaccination. In addition, all but two states offer nonmedical exemption on religious or philosophical grounds,” Lo and Hotez wrote. “Given trends in declining vaccine coverage, our study predicts that removal of nonmedical personal belief exemptions would substantially reduce the risk of measles in the U.S.” — by Katherine Bortz
Disclosure: The researchers provide no relevant financial disclosures.