Dr. Kumanan Wilson, Canadian Research Chair for public health, shows a map of Europe - all the dots indicate outbreaks of vaccine-preventable viral illnesses in 2012.

The Ottawa Cancer Foundation has reversed its decision to hire actress and model Jenny McCarthy to headline its one-day fitness fundraiser Bust A Move.

In a statement released late Friday afternoon, the foundation said McCarthy would be replaced by Canadian celebrity fitness instructor and former CFL player Tommy Europe.

The statement said that since the announcement of McCarthy's appearance, "...attention has shifted away from breast cancer awareness and fundraising."

On Tuesday, McCarthy was revealed as Bust A Move's guest fitness instructor, which caused many to question why an organization supporting cancer research would invite someone with a history of promoting erroneous ideas about health and disease.

Despite reams of scientific research to the contrary, McCarthy writes and speaks publicly about the supposed link between child vaccination and autism. The former Playboy Playmate also blames her son's autism on vaccinations.

Word of McCarthy's appearance at a charity cancer event sparked a #dropjenny hashtag on Twitter, which generated many comments about whether the actress was a credible choice. Similar online debate occurred on Bust A Move's Facebook page.

Other supporters of the cancer foundation and immunologists also expressed concern about its choice of McCarthy for this year's event. Ottawa resident Greg Mills said he'd think twice before donating.

"She's been very vocal in support for really quackery rather than anything that could achieve results," said Mills. "It is astounding that a breast cancer foundation, or activity would bring her on for that. I think there are better choices out there."

In an effort to equal or beat the $350,000 Bust A Move raised last year, with the help of legendary fitness guru Richard Simmons, McCarthy was tapped to headline the March 2013 event.

Dr. Kumanan Wilson, Canada Research Chair for Public Health who has studied vaccine safety, says celebrities have a lot of influence and that McCarthy's misinformation could have negative health impacts.

Wilson said there has been significant research done on the safety of vaccines and that there is absolutely no link between child vaccination and autism.

"Concerns need to be put forward and they need to be studied," said Wilson. "But in this case it has been studied and there is no association."

On her Twitter feed Friday afternoon, McCarthy blamed the cancellation of her appearance on scheduling conflicts: “So, so sorry Ottawa! I had to pull out of (the) event because of my new show taping conflict but will be back in a few months to make up for it!”