A Sydney couple in hiding after refusing to have their newborn baby vaccinated against hepatitis B also have a three-year-old child who could be carrying the virus.
The parents fled their Croydon Park home on Thursday to avoid police and Department of Community Services (DoCS) officials, after they refused to have their three-day-old son vaccinated at Royal Prince Alfred Hospital.
The baby's mother, who is from China, was diagnosed with hepatitis B several years ago.
On medical advice, DoCS took a recommendation to the NSW Supreme Court last week and ordered the parents to vaccinate the baby.
Yesterday, the court made the decision to continue the orders, with the case due back in court today.
"This is a day by day proposition," DoCS spokeswoman Annette Gallard told reporters in Sydney yesterday.
The baby's parents, who have not been named, also have a three-year-old child, who DoCS believe has also not been vaccinated against hepatitis B.
"We understand that there is another child, but we were unaware at the birth of the child that there was an issue, so we did not have the opportunity to act," Ms Gallard said.
"We're very concerned that the health of both of these children is monitored and that the little baby in particular can be vaccinated."
Ms Gallard said the department was working with police to find the family and had spoken with the parents on a number of occasions.
"We've had some phone contact with them from time to time and obviously each time we're urging them to come forward," she said.
The parents believe the illness, which can cause liver cancer and cirrhosis, can be managed more effectively without vaccination.
They fear the vaccination could cause their child neurological damage.
Hepatitis Australia CEO Helen Tyrrell said the hepatitis B vaccination was extremely safe.
"The incidences of acute reactions to the hepatitis B vaccine are extremely rare. . . and if they do occur, they are usually short-lived," she told AAP.
"So, if you're weighing up the risks of vaccination versus not vaccination, then we would certainly recommend vaccination."
Ms Tyrrell said mother-to-child transmission during the birth process and immediately after was common, with the chance of transmission between five and 40 per cent.
If a baby was vaccinated, the chances of infection were "very, very low", she said.
Vaccinations are not compulsory in Australia, but it's NSW health policy for babies born to hepatitis B mothers to be given the immunoglobulin injection within 12 hours of birth.
Ms Tyrrell said a baby who developed hepatitis B had a 95 per cent chance of developing the chronic form of the disease, which carried with it a "very high chance" of liver cancer among other problems which are difficult to reverse.
Ms Gallard refused to speculate on whether the parents would be charged, but said DoCs would be taking both medical and legal advice about what to do next.
"We will make a decision in the best interest of the family," she said.
"But at this stage, we just want to get the baby vaccinated."