Researchers have found no link between the amount of vaccine antigens received by the age of 2 years and the likelihood of developing autism.
Yet another study has found no link between childhood vaccines and autism. The new study
, published in the April 2, 2013, edition of the Journal of Pediatrics
, analyzed the association between children’s cumulative exposure to vaccine antigens up to 2 years of age and the likelihood of developing the condition.
The researchers drew on data from a case-control study carried out in 3 managed care organizations of 256 children with autism spectrum disorder (ASD) and 753 matched controls. The children in the study were born between 1994 and 1999 and were aged 6 to 13 at the time of data collection. For each of 3 age ranges (birth to 3 months, birth to 7 months, and birth to 2 years), researchers looked at the association between total cumulative exposure to antibody-stimulating proteins and polysaccharides (antigens) from childhood vaccinations and the following outcomes: ASD, autistic disorder, and ASD with regression.
The results showed that the adjusted odds ratio of developing ASD associated with each 25-unit increase in total antigen exposure was 0.999 for cumulative exposure to 3 months of age, 0.999 for cumulative exposure to 7 months of age, and 0.999 for cumulative exposure to 2 years of age. In addition, no association was found between cumulative exposure to vaccine antigens and likelihood of developing autistic disorder or ASD with regression. Nor was a child’s maximum antigen exposure in a single day associated with an increased risk of ASD.
The researchers also looked at the association between receiving the whole-cell pertussis vaccine, which contains several thousand antigen units, and the condition outcomes. They found that the odds ratio for each increase of 1 whole-cell pertussis vaccine dose was 0.956 for ASD, 0.989 for AD, and 0.761 for ASD with regression.
The researchers conclude that increased exposure to vaccine antigens in early childhood is unrelated to risk of developing autism. “These results indicate that parental concerns that their children are receiving too many vaccines in the first 2 years of life or too many vaccines at a single doctor visit are not supported in terms of an increased risk of autism,” they write.
The researchers also note that since the whole-cell pertussis vaccine has been removed from the vaccine schedule, the antigen load for children today is much lower than it was in the late 1990s even though children today receive more vaccines. The maximum antigen load by age 2 was 315 in 2012, compared with several thousand in the late 1990s.