This article is more than 5 years old. Information may no longer be current.
Study reveals nonmedical vaccine exemption ‘hotspots’ in US
Click Here to Manage Email Alerts
Data show that nonmedical vaccine exemptions have increased in 12 of the 18 states that allow exemptions for philosophical beliefs, with high rates of exemptions — “hotspots,” as researchers called them — observed in many metropolitan areas.
This rise in antivaccine activity may put unvaccinated children at risk for contracting preventable diseases and leave areas vulnerable to future outbreaks, said Peter J. Hotez, MD, PhD, director of Texas Children’s Hospital Center for Vaccine Development and dean of the National School of Tropical Medicine at Baylor College of Medicine, and colleagues.
According to Hotez and colleagues, the 18 states that allow vaccine exemptions for philosophical beliefs are Arkansas, Arizona, Colorado, Idaho, Louisiana, Maine, Michigan, Minnesota, Missouri, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Texas, Utah, Washington and Wisconsin.
The researchers used state-level data on nonmedical vaccine exemptions to investigate trends occurring between the 2009-2010 and 2016-2017 school years. The number of children entering kindergarten with documentation of nonmedical vaccine exemptions was compared with the number of kindergarten enrollments in each state to calculate the rate of exemptions. Most data were collected from MMWR reports and state health departments. Although the CDC did not provide information regarding nonmedical vaccine exemptions for the 2010-2011 school year, 10 states included in the analysis collected individual data.
Hotez and colleagues observed an upward trend of nonmedical vaccine exemptions beginning in 2009 in 12 states: Arkansas, Arizona, Idaho, Maine, Minnesota, Missouri, North Dakota, Ohio, Oklahoma, Oregon, Texas and Utah, with the greatest increase in exemptions occurring between 2009 and 2014. Some of these states have demonstrated a slowing of exemptions; however, rates are still increasing in certain states like Arkansas, North Dakota, Ohio, Oklahoma, Texas and Utah.
“Parents are opting their children from vaccines because of erroneous beliefs that vaccines cause autism or other neurodevelopmental delays,” Hotez told Infectious Disease News. “As a vaccine scientist, pediatrician and autism dad, I’ve been working to raise awareness that there is no link between vaccines and autism. Despite these efforts, nonmedical exemptions are rising in the U.S., where antivaccine groups are well-funded and well-organized.”
When county-level exemption rates were assessed, eight Idaho counties had some of the highest rates of exemptions: Camas (26.7%), Bonner (19.7%), Valley (18.2%), Custer (17.1%), Idaho (16.1%), Boise (15.6%), Kootenai (14.9%) and Boundary (14.6%). Wisconsin’s Bayfield County had a vaccine exemption rate of 15.7%, and Morgan County in Utah had an exemption rate of 14.6%. Almost all locations were similar in that fewer than 50,000 people lived within these mostly rural areas.
However, the researchers noted that large metropolitan areas also demonstrated high rates of nonmedical vaccine exemptions. More than 400 kindergarteners obtained exemptions in the following counties associated with large metropolitan areas: King and Spokane Counties, Washington (Seattle and Spokane); Maricopa County, Arizona (Phoenix); Salt Lake and Utah Counties, Utah (Salt Lake City and Provo); Multnomah County, Oregon (Portland); Oakland, Macomb and Wayne Counties, Michigan (Troy, Warren and Detroit); Harris, Tarrant, Collin and Travis Counties, Texas (Houston, Fort Worth, Plano and Austin); Allegheny County, Pennsylvania (Pittsburgh); Jackson County, Missouri (Kansas City).
High rates of nonmedical vaccine exemptions in these metropolitan areas suggest that quickly spreading outbreaks of vaccine-preventable diseases among children are plausible, according to Hotez and colleagues. They reported that the areas with the largest number of unvaccinated children have busy international airports, which may increase the likelihood of further infection.
Additionally, a significant inverse relationship was observed in states that had high rates of nonmedical vaccine exemptions and immunization with the measles, mumps and rubella vaccine. States that banned nonmedical exemptions, including Mississippi, California and West Virginia, had the highest uptake rates and the lowest rates of disease, the researchers said.
“Whereas measles was thought to have been eliminated from the U.S. in 2000, we have seen local outbreaks of this vaccine-preventable disease and others, like whooping cough, in recent years due to inadequate immunization coverage in schools,” the researchers wrote. “For instance, a child with a nonmedical exemption from the measles, mumps and rubella vaccine is 35 times more likely to contract measles than is a vaccinated child. Moreover, a child without the diphtheria, tetanus and acellular pertussis vaccine is three times more likely to contract pertussis than is a vaccinated child.”
Hotez said pediatricians should become aware of talking points surrounding the issue of vaccine hesitancy and how to educate parents about immunizations.
“Unfortunately, pediatricians are spending more and more time in their practices trying to convince vaccine-hesitant parents that vaccines are safe,” he said. – by Katherine Bortz
- Reference:
- Olive JK, et al. PLoS Med. 2018;doi:10.1371/journal.pmed1002578.
Disclosures: The authors report no relevant financial disclosures.