Parents are urged to have their children vaccinated against chickenpox after a survey found many were avoiding it because they thought people were better off developing natural immunity to the highly contagious disease.
WA doctors say the results show they still face a battle to convince people that chickenpox can cause serious complications such as pneumonia, and birth defects in unborn babies.
Health Department officials are launching a public education campaign, focusing on parents of preschoolers, to lift lagging immunisation rates for the disease which is caused by the varicella zoster virus and commonly causes an itchy rash and blisters.
From this month, chickenpox has been added to the list of diseases for which vaccines are required for a child to be considered "fully vaccinated" on the Australian Childhood Immunisation Register.
The change is likely to lower the State's immunisation rates further below the nationally accepted target of 90 per cent.
A recent survey of parents' views about chickenpox found that the main reasons for not using the vaccine were that they did not consider it as effective as natural immunity and did not see chickenpox as a serious disease.
It comes as new figures show a fall in the rate of WA schoolboys completing the three-dose course of the human papilloma virus vaccine, which protects against cervical and throat cancers and genital warts.
Last year, only 86 per cent of boys had the three doses, compared with 92 per cent of girls.
Australian Medical Association WA president Michael Gannon said there was a long way to go in improving immunisation rates.
"As an obstetrician, I'm concerned because chickenpox is a particularly nasty and dangerous virus in pregnant women, and while we would expect about 90 per cent of women who grew up in WA to be immune through previous exposure or having been vaccinated, some women are vulnerable," Dr Gannon said.
"A proportion of children who get chickenpox infection will develop severe complications like pneumonia and inflammation of the brain, and they can be left with life-long disabilities or it can be fatal."
Dr Gannon said there would always be a small minority who rejected the scientific evidence in favour of immunisation but he believed it was possible to get vaccination rates up to 95 per cent.
The vaccine is free for children aged 18 months and is also offered through the Year 8 school-based immunisation program.