A new research report from Kaiser Permanente shows that children with autism and their younger siblings are "significantly less likely" to be fully vaccinated than the general population.
The research, which was published Monday in JAMA Pediatrics, studied more than 3,700 children with autism spectrum disorders (ASD) who were diagnosed by the age of five. The study also featured nearly 500,000 children without ASD born between Jan. 1, 1995 and Sept. 30, 2010; and their respective younger siblings born between Jan. 1, 1997 and Sept. 20, 2014.
"In this large and comprehensive study, we found that after children received an autism diagnosis, the rates of vaccination were significantly lower when compared with children of the same age who did not have an autism diagnosis," said Ousseny Zerbo, the lead author of the study and a PhD postdoctoral fellow with the Kaiser Permanente Northern California division of Research.
Researchers looked into if the children received vaccines recommended by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices. The information came from Kaiser Permanente locations in California, Colorado, Oregon and Washington, and Marshfield Clinic in Wisconsin.
"There were large disparities in vaccination rates between children with and without autism spectrum disorders, as well as between their siblings, across all age groups and after adjusting for important confounding factors," senior author and director of the Kaiser Permanente Vaccine Study Center Nicola Klein said.
Ninety-four percent of children ages seven and older without ASD received all vaccines recommended between four and six years of age, opposed with 82 percent of those with ASD. As for the measles, mumps, rubella vaccine, 96 percent of those without ASD were vaccinated, compared to 84 percent with ASD.
The proportion of children fully vaccinated with recommended vaccines was lower with the younger siblings of children with ASD compared with younger siblings of children without ASD.
"Numerous scientific studies have reported no association between childhood vaccination and the incidence of autism spectrum disorders," said Frank DeStefano, co-author of the study. "Nonetheless, this new study suggests that many children with autism and their younger siblings are not being fully vaccinated.
"We need to better understand how to improve vaccination levels in children with autism spectrum disorder and their siblings so they can be fully protected against vaccine-preventable diseases."