A new study shows that one in four parents believes some vaccines can trigger autism.

The study is based on a survey of more than 1,500 parents that was conducted last year. About 12 percent of parents said they had refused to allow their children to receive a vaccine that a doctor recommended. 

Those parents tended to shy away from four vaccines: 

• Human papillomavirus vaccine, because of concerns about side effects
• Vaccine for meningococcal diseases, because of the risk of Guillain-Barré syndrome, an immune system disorder
• The shot for measles, mumps and rubella, because of potential autism risk
• Chickenpox vaccine