The number of Australian babies not fully immunized is now one in 12 and parents registering a conscientious objection has leapt from 4,271 in 1999 to more than 30,000, according to a booklet released on Monday.

A 20-page booklet launched by the Academy of Science Monday explains that many more children will die from diseases such as measles, mumps and diphtheria than will be harmed by the side effects of immunization and why it is better to gain immunity from vaccination than from the disease.

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

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

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