A new report published in the Journal of the American Medical Association confirmed, once again, that there is no link between the MMR vaccine and children developing autism. This new report is another in a string of research papers which debunk the dangerous myth that the MMR vaccine is linked to children developing autism.
For this new study, researchers conducted a cohort study of over 95,000 children enrolled in a large commercial health care plan. The children received either 1, 2 or no doses of the MMR vaccine from birth to the age of 5 between 2001 and 2012. Many of the children within the cohort group also had older siblings who were continuously enrolled in the health care plan for at least 6 months between 1997 and 2012.
Using the databases, the researchers studied the risk of developing autism between those children who received the MMR vaccine compared to those who did not. They also looked at the risks associated with the MMR vaccine causing autism in children who had older siblings diagnosed with ASD, as well as the ages the vaccines were given.
From the data collected, the researchers were able to conclude that the MMR vaccine was NOT associated with any increased risk of children developing autism, even for children in a higher risk group; those who had older siblings with ASD.
What was concerning was the children with older siblings diagnosed with ASD were 10% less likely to be vaccinated against measles, mumps and rubella than those with unaffected siblings. The researchers noted “MMR vaccination rates for children with older siblings with ASD were lower (73% at age 2 years [n = 1409] and 86% [n = 1660] at age 5 years).”
Even though Andrew Wakefield’s 1998 study, which connected autism to vaccines, was retracted and dubbed an “elaborate fraud”, the myth has prevailed. The result is that many parents have refused to vaccinate their children against mumps, measles and rubella in fear that their child might develop autism.
The researchers concluded “These findings indicate no harmful association between MMR vaccine receipt and ASD even among children already at higher risk for ASD”.
These new findings should help address concerns some parents still have as to whether there is a link between vaccines and autism.
Written by Victoria Driscoll – NeuroscienceNews.com
Image Source: The image is credited to the NIH and is in the public domain
Original Research: Full open access research for “Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism” by Anjali Jain, MD; Jaclyn Marshall, MS; Ami Buikema, MPH; Tim Bancroft, PhD; Jonathan P. Kelly, MPP; and Craig J. Newschaffer, PhD in JAMA. Published online April 21 2015 doi:10.1001/jama.2015.3077
Abstract
Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism
Importance Despite research showing no link between the measles-mumps-rubella (MMR) vaccine and autism spectrum disorders (ASD), beliefs that the vaccine causes autism persist, leading to lower vaccination levels. Parents who already have a child with ASD may be especially wary of vaccinations.
Objective To report ASD occurrence by MMR vaccine status in a large sample of US children who have older siblings with and without ASD.
Design, Setting, and Participants A retrospective cohort study using an administrative claims database associated with a large commercial health plan. Participants included children continuously enrolled in the health plan from birth to at least 5 years of age during 2001-2012 who also had an older sibling continuously enrolled for at least 6 months between 1997 and 2012.
Exposures MMR vaccine receipt (0, 1, 2 doses) between birth and 5 years of age.
Main Outcomes and Measures ASD status defined as 2 claims with a diagnosis code in any position for autistic disorder or other specified pervasive developmental disorder (PDD) including Asperger syndrome, or unspecified PDD (International Classification of Diseases, Ninth Revision, Clinical Modification 299.0x, 299.8x, 299.9x).
Results Of 95 727 children with older siblings, 994 (1.04%) were diagnosed with ASD and 1929 (2.01%) had an older sibling with ASD. Of those with older siblings with ASD, 134 (6.9%) had ASD, vs 860 (0.9%) children with unaffected siblings (P < .001). MMR vaccination rates (≥1 dose) were 84% (n = 78 564) at age 2 years and 92% (n = 86 063) at age 5 years for children with unaffected older siblings, vs 73% (n = 1409) at age 2 years and 86% (n = 1660) at age 5 years for children with affected siblings. MMR vaccine receipt was not associated with an increased risk of ASD at any age. For children with older siblings with ASD, at age 2, the adjusted relative risk (RR) of ASD for 1 dose of MMR vaccine vs no vaccine was 0.76 (95% CI, 0.49-1.18; P = .22), and at age 5, the RR of ASD for 2 doses compared with no vaccine was 0.56 (95% CI, 0.31-1.01; P = .052). For children whose older siblings did not have ASD, at age 2, the adjusted RR of ASD for 1 dose was 0.91 (95% CI, 0.67-1.20; P = .50) and at age 5, the RR of ASD for 2 doses was 1.12 (95% CI, 0.78-1.59; P = .55).
Conclusions and Relevance In this large sample of privately insured children with older siblings, receipt of the MMR vaccine was not associated with increased risk of ASD, regardless of whether older siblings had ASD. These findings indicate no harmful association between MMR vaccine receipt and ASD even among children already at higher risk for ASD.
“Autism Occurrence by MMR Vaccine Status Among US Children With Older Siblings With and Without Autism” by Anjali Jain, MD; Jaclyn Marshall, MS; Ami Buikema, MPH; Tim Bancroft, PhD; Jonathan P. Kelly, MPP; and Craig J. Newschaffer, PhD in JAMA. Published online April 21 2015 doi:10.1001/jama.2015.3077
