27344
Incomplete Vaccination and Risk of Autism Spectrum Disorder
Objectives: We examined the relationship between completion of 6 types of vaccinations in childhood and higher risk for ASD, using an internal replication design.
Methods: Two large South Korean epidemiologic samples were used to: 1) Generate hypotheses about completion of all 6 types of vaccination and increased risk for ASD in a Discovery Sample (DS: N=10,006); and, 2) Replicate the initial findings in a Replication Sample (RS: N=29,381). Mothers reported completion of 6 types of vaccination, including BCG, HepB, MMR, JEV (Japanese Encephalitis Vaccination), DTaP and Polio. Completion of the vaccinations were categorized into three groups: <3 , 4-5 , and 6 vaccines. Three levels of risks for ASD diagnosis was estimated with the Autism Spectrum Screening Questionnaire(ASSQ): low (ASSQ<10), intermediate (ASSQ=10-14), and high (ASSQ≥15) risk. Multivariate ordinal regression was performed: model 1 controlled for demographic factors and model 2 controlled for demographic and confounders (family history of psychiatric disorders, prematurity, and birth order).
Results: 84.3 % of DS and 80.1% of RS were fully vaccinated. After adjusting for demographic covariates and confounders, children who were vaccinated incompletely were at increased ASD risk when compared to those fully vaccinated in the DS (adjusted odds ratio [aOR] = 2.33, 95% CI, 1.53-3.56 in vaccination less than 3; aOR=1.42, 95% CI, 1.17-1.73 in 4-5 vaccination). This initial finding was replicated in the RS (aOR=2.19, 95% CI, 1.80-2.67 in vaccination less than 3; aOR=1.44, 95% CI, 1.32-1.58 in 4-5 vaccination).
Conclusions: Our data suggest that vaccination does not increase risk for ASD but may carry protective effects against ASD. Vaccination has proven to be a successful and effective public health strategy to prevent life-threatening infectious disease in childhood, and to improve the well-being and health of children. When replicated in other populations, the benefit of vaccination might extend to its protective effect for common childhood neurodevelopmental disorders, like ASD.