Background. This pilot study investigated vaccine decision making, i.e., the relationships between knowledge and attitudes towards autism spectrum disorders (ASD), scientific literacy, attitudes toward the (MMR) vaccine, and children’s MMR vaccination status. Methods. A sample of 132 parents and expectant parents (mean age 38.40 years; >60% with university education) participated in a survey where they were asked about their knowledge of ASD, attitudes towards ASD and MMR, and their children’s MMR vaccine status. The participants also completed a standardized science test (The American College Test) to test their scientific literacy. Results. Knowledge of ASD was positively correlated with attitudes towards ASD. Attitudes towards ASD were positively correlated with scientific literacy and attitudes towards MMR. Attitudes towards MMR were positively correlated with MMR vaccine status (i.e., vaccination decision). Discussion. Factors other than scientific literacy seem to contribute towards children’s MMR vaccine status such as attitudes towards MMR. However, these are preliminary findings and need to be interpreted with caution.