As stars mums like Jenny McCarthy continue to fight against vaccinations, claiming medical research suggests their kids could be at risk from serious illness, mother of two Bell has joined Amanda Peet and those that are for inoculation, because she believes it's her responsibility to make sure all kids are not put at risk by a decision she and her husband Dax Shepard have made.

She tells Good Housekeeping magazine, "I thought I would be anti-vaccination before I had kids. I'm very crunchy (earthy), and happily so. But there is a lot of scientific, proven information out there that shows why vaccinations are necessary.

"Kids with autoimmune diseases, kids who are receiving cancer treatments - they can't be vaccinated because their immune systems (can't handle it). If your kid has leukaemia, he can't get vaccinations; if he then goes to school with my kid and I chose not to give my kid vaccinations, I'm putting your kid at risk. To me, that's unacceptable.

"There are the weak among us whom we have to protect. As moms, our responsibility is not just to our kids - it's to all the other kids, too. People often misplace fear. Your child is 100 times more likely to be struck by lightning than to have a severe reaction to a vaccine. That's a fact."