Jenny McCarthy is a former Playboy bunny, not an academic expert, a doctor or a vaccine researcher. Yet 24% of parents surveyed recently by the University of Michigan say they place “some trust” in information provided by celebrities such as McCarthy about the safety of vaccines.

Most parents reported they relied on their child’s doctor for accurate information. But the opinions of friends, relatives, public health officials and nurses were also considered, according to a national survey of 1,552 parents of children under 18 that asked them to rate the degree to which they trusted various sources of information about vaccines using the following terms: a lot, some or none. (More on Time.com: A Little-Known Problem in Children With Autism: Wandering Away)

Researchers were interested in assessing which sources of information about vaccines parents trust and how best to disseminate evidence of vaccine safety, according to the study, which was published online this month in the journal Pediatrics.

Most parents — 76% — ranked their doctor’s advice highest, but 67% placed “some” trust in family and friends and 65% trusted parents who thought vaccines had harmed their children. Just 2% of parents trusted celebrities “a lot,” but 24% trusted them to “some” extent.

“It’s great that parents trust physicians as their primary source for vaccine information, but it’s terribly concerning that 24% of parents have some trust in information provided by celebrities,” says Gary Freed, chief of the Division of General Pediatrics and director of the Child Health Evaluation and Research (CHEAR) Unit at the University of Michigan. (More on Time.com: Bill Gates Chats With CNN’s Sanjay Gupta About the Vaccines-Autism Myth)

Among Hispanics, 40% of parents reported they have “a lot” or “some” trust in celebrities’ insight. In general, researchers found that mothers, regardless of nationality, were more liable to trust celebrities, news articles and television shows and other parents who said vaccines had harmed their children.

Freed says the media is at fault for giving celebrities such as McCarthy — the most vocal star to have denounced vaccination, associating it with autism — a stage. McCarthy has written a book, Healing and Preventing Autism: A Complete Guide, and speaks regularly in favor of chelation therapy, or removal of heavy metals from the body, which she says cured her son.

“I don’t understand why when a celebrity says something about which they have no training, that is reported more than someone who has done rigorous scientific training,” says Freed. “Celebrities are juxtaposed to medical experts as credible sources of information by the media. As long as that continues to occur, the public will continue to assume they are as credible as credible sources really are.”

Freed is not advocating blind faith in physicians; parents deserve to have as much information as they need to feel comfortable about immunizing their children, and pediatricians should take time to discuss their concerns. (More on Time.com: Autism, Vaccines and Fraud: Q&A With Author Seth Mnookin)

“The message for physicians is to understand that people use many different sources for their information,” says Freed, pointing out that numerous studies have confirmed that vaccinations don’t cause autism. “Physicians need to help deconstruct myths for parents and help them understand the actual data.”