Whooping cough seems to be running rampant in New South Wales. The Australian state has recorded the highest rate in 17 years.
More than 6,500 people contracted the disease in 2008, despite the wide availability of vaccinations and restrictions on children who are not vaccinated.
It is the highest number of cases since 1991.
Australia-wide there were more than 12,000 reports of the infection last year.
Whooping cough causes long bursts of coughing and can be fatal in babies and young children.
Professor Mark Ferson from the South East Area Health Service says cases are continuing into January.
"We're concerned about the number of cases,' he said.
"The disease is affecting all age groups in the community, but the ones we're most concerned about are the babies of a few month of age in which may be very serious or fatal.
"People have been vaccinated but we know that the effects of vaccination don't last particularly long."
Professor Ferson says booster whooping cough vaccinations may be needed to cut rates of the disease.
"We're strongly recommending that people who are around babies up to a few months of age should have the booster vaccination," he said.
"The disease is affecting all age groups but the highest rates are in children, particularly in the 10 to 14 year age group. The adolescent booster is also recommended at that age and there will be vaccinations in 2009 for that age group."
The acting NSW Health Minister, Ian MacDonald, says no-one has died but the disease is clearly at a peak.
"The disease in the past had killed many hundreds of people in its peaks prior to vaccination, so vaccination is the key point," he said.
"It is important that we keep vaccination levels up and that we don't drop off."
An increasing number of cases of the highly infectious illness have been reported on the Gold Coast and northern NSW areas in recent weeks.
Gold Coast pediatrician Dr Darrell Price said the outbreak would not be as severe if the State Government provided free vaccinations every 10 years for both adults and children.
He said older members of the community needed to be aware that if they had not been vaccinated since they were children, they were just as much at risk.
"In the last few months we have seen an increase of children and babies being admitted to hospital with whooping cough," he said.
"This week, all the babies in hospital have got the illness from an adult. The adult population should be getting vaccinated.
"The majority of the adult population has not been immunised since they were four."
Gold Coast population health medical officer Dr Don Staines said whooping cough normally worked on a three to four-year cycle.
"We do have an excess number of cases of whooping cough and it is a very dangerous condition, producing extreme toxicity in children," he said.
"There is the issue that parents are passing the illness on to their children. We are seeing grandparents who have not been vaccinated since they were children who are getting the infection and passing it on to their grandchildren."
Dr Staines said the disease was now circling the Coast, affecting people who would not normally come in contact with it.
"This is not a disease anyone should take lightly. It is a very dangerous condition," he said.
"Everyone needs to realise that if you are coughing longer than a week you could have whooping cough."