The Grapevine

More Parents Are Not Vaccinating Their Children, Increasing Risk Of Disease Outbreaks

Some parts of the United States have seen a rise in non-medical exemptions from childhood vaccinations, according to researchers from Baylor College of Medicine and the Texas Children's Hospital Center.

The study titled "The state of the antivaccine movement in the United States: A focused examination of nonmedical exemptions in states and counties" was published in PLOS Medicine on June 12.

Children affected by anti-vaccine attitudes

Currently, 18 states in the country allow vaccine exemptions for philosophical beliefs, including Arizona, Michigan, Ohio, Pennsylvania, Texas, Utah, Washington etc. In 12 of these states, the study found an increasing number of children enrolling in kindergarten with a non-medical exemption since 2009. 

Usually, parents file a one-time or annual form with a school district providing a personal objection they have to vaccination. 

"Parents are opting their children from vaccines because erroneous of beliefs that vaccines cause autism or other neurodevelopmental delays," said lead author Peter Hotez.

"Our concern is that the rising [non-medical exemptions] linked to the anti-vaccine movement in the US will stimulate other countries to follow a similar path," the authors wrote, urging stricter legislative action to close non-medical exemptions from vaccination.

The risks of non-medical exemptions

Higher rates of non-medical exemptions in individual states were linked to lower rates of vaccination coverage for measles, mumps, and rubella (MMR). A child with a non-medical exemption from the MMR vaccine is 35 times more likely to contract measles compared to a vaccinated child.

A near-complete vaccination coverage (90 to 95 percent) is required to establish immunity and prevent the spread of highly infectious diseases among children, the authors stated. They cited the measles outbreak in California during 2014–2015 which was thought to have occurred as a result of parental resistance to vaccination. 

"High rates of non-medical exemptions have been associated with higher rates of vaccine-preventable diseases. Local clusters of vaccine exemptions geographically overlap with outbreaks of pertussis," stated Dr. Saad B. Omer from Emory University, Georgia, in a previous 2017 study.

More strategies to control outbreaks

Infection prevention responses targeting measles and mumps outbreaks were highlighted in a new research presented at the 45th Annual Conference of the Association for Professionals in Infection Control and Epidemiology (APIC). Researchers also noted that 67 percent of facilities lacked a designated infection preventionist (IP) in addition to being unfamiliar with testing recommendations for mumps.

"Many of the providers were unfamiliar with mumps because they've never seen it before," said Thi Dang, lead author of one of the case studies. "This gap, and others that we identified provide valuable information for any outbreaks that we might be faced with in the future, as we better understand aspects of symptom monitoring, vaccination recommendations, and control measures."

Encouraging vaccinations and increasing awareness about symptoms among medical professionals and patients can go a long way in eradicating outbreaks, according to the research.

The HealthPartners care system, which provided care for 24 cases of measles during the 2017 Minnesota outbreak, activated a system-wide command center. Here, IPs collaborated to respond to the outbreak as an integrated system by sharing information in real-time and adjusting prevention strategies in a timely manner.