OAKLAND, Calif. — Children with autism and their
younger siblings are significantly less likely to be fully vaccinated
than the general population, according to new Kaiser Permanente research
published today in JAMA Pediatrics. This is despite multiple well-publicized studies showing no link between autism and childhood vaccinations.
“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 lead author Ousseny Zerbo, PhD, postdoctoral fellow with the Kaiser Permanente Northern California Division of Research.
The retrospective matched cohort study, “Vaccination Patterns in
Children After Autism Spectrum Disorder Diagnosis and in Their Younger
Siblings,” included more than 3,700 children with autism spectrum
disorders diagnosed by 5 years of age, and 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. 30,
2014.
The researchers reviewed whether the children received vaccines recommended by the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices. The data were drawn from six sites participating in the CDC’s Vaccine Safety Datalink: 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,” said senior author Nicola Klein, MD, PhD, director of the Kaiser Permanente Vaccine Study Center.
For example, among children aged 7 years or older, 94 percent of
those without an ASD received all vaccines recommended between 4 and 6
years of age, compared with 82 percent of those with an ASD; and for the
measles, mumps, rubella (or MMR) vaccine, 96 percent of those without
an ASD were vaccinated, compared with 84 percent of those with an ASD.
In addition, the proportion of children who were fully vaccinated
with the recommended vaccines was also lower among younger siblings of
children with ASD compared with younger siblings of children without
ASD. For example, for vaccines recommended between one and 11 months, 73
percent of younger siblings of children with ASD were fully vaccinated
compared to 85 percent of younger siblings of children without ASD.
“Numerous scientific studies have reported no association between
childhood vaccination and the incidence of autism spectrum disorders,”
said co-author Frank DeStefano, MD, MPH, Immunization Safety Office,
Centers for Disease Control and Prevention. “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.”
This study was funded by the Centers for Disease Control and Prevention.
In addition to Dr. Klein, Zerbo and Dr. DeStefano, co-authors were
Sharareh Modaressi, MPH, Kristin Goddard, MPH, Edwin Lewis, MPH, Bruce H. Fireman, MA, of the Kaiser Permanente Vaccine Study Center, Oakland, California; Matthew F. Daley, MD, Kaiser Permanente Institute for Health Research, Denver; Stephanie A. Irving, MHS, Kaiser Permanente Center for Health Research, Portland, Oregon; Lisa A. Jackson, MD, MPH, Kaiser Permanente Washington Health Research Institute, Seattle; James G. Donohue, DVM, PhD, Marshfield Clinic Research Institute, Wisconsin; Lei Qian PhD, Darios Getahun, MD, PhD, Kaiser Permanente Department of Research and Evaluation, Pasadena, California; and Michael M. McNeil, MD, MPH, Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta.
“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 lead author Ousseny Zerbo, PhD, postdoctoral fellow with the Kaiser Permanente Northern California Division of Research.
Ousseny
Zerbo, PhD, is a Post-Doctoral Researcher in the Vaccine Study Center
at Kaiser Permanente Northern California Division of Research.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes
and disseminates epidemiologic and health services research to improve
the health and medical care of Kaiser Permanente members and society at
large. It seeks to understand the determinants of illness and
well-being, and to improve the quality and cost-effectiveness of health
care. Currently, DOR’s 550-plus staff is working on more than 350
epidemiological and health services research projects. For more
information, visit divisionofresearch.kaiserpermanente.org or follow us @KPDOR.
