A young boy is pictured receiving a vaccine at a health center in Glasgow, Scotland, Sept. 3, 2007. Jeff J Mitchell/Getty Images)

Autistic children and their younger siblings are much less likely to be fully vaccinated compared to those without the disorder, according to new research published Monday in the journal JAMA Pediatrics.

"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, a doctor at the Kaiser Permanente Northern California Division of Research.

The team of researchers studied data on 3,729 children with autism spectrum disorder (ADS) born between 1995 and 2010 and their younger brothers and sisters. The team also compared the information to 592, 907 children of the same age without the diagnosis.

ADS is used to describe "a spectrum" of symptoms, skills, and levels of disability in an individual. Those with the disorder often experience social problems including difficulty communicating and expressing themselves, which is typically diagnosed by the age of 2, according to the National Institue of Mental Health.

The study focused on whether the subjects received all vaccinations recommended by the Centers for Disease Control and Prevention's Advisory Committee.

The study's senior author, Dr. Nicola Klein, revealed the report indicated that about "80 percent of children with autism received all vaccines recommended for children between ages 4 and 6, versus 94 percent among children without autism."

The research also showed that the proportion of children with the recommended vaccinations including polio, chicken pox and measles, mumps and rubella, was lower among the younger siblings diagnosed with ASD, alongside the younger siblings of the children without the disorder.

"Nonetheless, this new study suggests that many children with autism and their younger siblings are not being fully vaccinated," said co-author Dr. Frank DeStefano, the CDC Director of Immunization Safety.

"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," Dr. DeStefano added.

In recent years, the rates of parents vaccinating their children have decreased. Notably, research has highlighted no association between vaccines and autism.