An international review involving more than 1.25 million children is further debunking long-held concerns about an association between vaccines and autism.

Scientists found no association between the developmental disorder and immunizations for measles, mumps, rubella, diphtheria, tetanus or whooping cough.

What’s more, they did not find any link between autism and thimerosal or mercury, which are sometimes used as preservatives in vaccines.

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The findings published in the journal Vaccine this month are based on a review of 10 previously published studies looking at the experiences of over a million kids.

“The data consistently shows the lack of evidence for an association between autism, autism spectrum disorders and childhood vaccinations, regardless of whether the intervention was through combination vaccines (MMR) or one of its components, providing no reason to avoid immunization on these grounds,” said Guy Eslick of the Sydney Medical School in Australia, the study’s senior author.

The review is just the latest evidence refuting a link between vaccines and autism.

Widespread concerns about immunizations emerged after a now-discredited 1998 study suggested an association. The initial study was retracted and subsequent reports backed by the U.S. Centers for Disease Control and Prevention and the Institute of Medicine found no link, yet many parents remain skeptical with a recent survey finding that 1 in 3 believe vaccines can cause autism.