Kristen Bell has told friends that if they don't get the whooping cough vaccination, they can't hold her baby.

Bell, who voiced the character of Anna in Disney film Frozen, said: "It's a very simple logic: I believe in trusting doctors, not know-it-alls."

Bell has two young daughters, Lincoln and Delta, with actor Dax Shepard.

During a conversation for charity drive This Bag Saves Lives, which raises money for malaria treatments, Bell said: "When Lincoln was born [in March 2013], the whooping cough epidemic was growing, and before she was 2 months old, we simply said [to friends]: 'You have to get a whooping cough vaccination if you are going to hold our baby.'"

The debate around vaccinations rages on in the States, with a measles outbreak in California prompting people to join sides of the debate.

'Anti-vaxxers' argue that immunisations can have fatal side-effects and that doctors should not meddle in personal medical choices.

An open letter Road Dahl wrote about his daughter Olivia dying of the disease raised the profile of the debate. In it, Dahl said that it was tantamount to child abuse if you don't vaccinate your children.

But the debate has now spread beyond the US. Dr Ava Easton, Chief Executive of The Encephalitis Society, says that measles encephalitis is still a deadly disease in modern Britain.

"Roald Dahl wrote his letter 30 years ago but still today in the UK alone, 6000 people are diagnosed with encephalitis each year, that's 16 people every day," she tells The Independent. "This, it seems, is also considered an underestimate as encephalitis is very difficult to diagnose and like in the case of Roald Dahl's daughter, is sadly often missed.