LEADING scientists say the anti-immunisation lobby is endangering children's lives because of the soaring number of parents refusing to vaccinate.

The number of Australian babies not fully immunised is now one in 12 and parents registering a conscientious objection has leapt from 4271 in 1999 to more than 30,000.

The figures have prompted 12 top researchers to launch a campaign this week to debunk the claims of groups that claim vaccinations are dangerous.

Professor Ian Frazer, who developed the cervical cancer vaccine, said he feared immunisation levels for some diseases were falling below those required to prevent deadly outbreaks.

And eminent biologist Sir Gustav Nossal has accused the anti-vaccination lobby of preventing the eradication of measles through its false claim that the vaccine against the disease caused autism.

A 20-page booklet to be launched today explains that many more children will die from diseases such as measles, mumps and diphtheria than will be harmed by the side effects of immunisation.

The booklet, launched by the Academy of Science, will also explain why it is better to gain immunity from a vaccination than from the disease.

Professor Frazer, who helped develop the document, warned of a dangerous fall in immunisation levels for diseases such as whooping cough.

Although 92 per cent of 12 to 15-month-old babies have been immunised against whooping cough, Professor Frazer said the disease spread more easily when the rate fell below 95 per cent.

Health Department figures show there were more than 7100 cases of whooping cough recorded across Australia in the first three months of 2012.

Professor Nossal said the anti-vaccination lobby was only able to campaign against immunisation because of its success in reducing the outbreak of infectious diseases.

Professor Frazer said it was because parents no longer saw cases of measles or mumps that they did not understand measles could kill a child and cause brain damage or that mumps could make a male sterile and that chicken pox could be fatal.

"As infectious diseases become less common, people are less aware of the need to vaccinate their children," Prof Frazer said.

And he noted that it was a "brave decision" by parents not to immunise their child when the child could not make that decision itself.

Father of two Jaime Sanchez said he and wife Genevieve felt strongly about immunisation.

The couple's daughters Eva, 6, and Lola, 4, had received all the recommended vaccinations, which meant they were fully protected for school and kindergarten.

"There's probably a few risks with any medical procedure but the risk of not doing it is much, much greater and statistics prove that out," he said.

"I think there's a lot of ill-advised fear-mongering from people who don't know what they're on about.

"But it's a hard one to bring up with people who have decided they don't want to vaccinate their kids."

He was concerned that unvaccinated children could pass on diseases to children who were too young to have been vaccinated.

"If you're not going to vaccinate your kids, that's fine but then don't bring them around mine," he said.

Children must be fully immunised for their families to claim the $726 Family Tax Benefit Part A supplement.

More than 30,000 children have a conscientious objection recorded.

The 20-page booklet explains to parents who may be worried about vaccine side effects that only three in every 10,000 children who receive the measles-mumps-rubella vaccine develop a fever high enough to cause seizures but 100 in 10,000 develop such a fever if they catch the disease.

One in four patients chronically infected with hepatitis B will die from cirrhosis of the liver or from liver cancer.

This risk is reduced to almost zero after the hepatitis B vaccine.

The booklet tackles claims that immunisation is linked to autism and says medical studies show the incidence of autism in people who had the measles-mumps-rubella vaccine is identical to that of people who did not have it.

The booklet is produced by the Australian Academy of Science and parents can access the document here.

- with Lauren Novak

Originally published as Danger as vaccination rates plunge