Cases of whooping cough are surging across Australia, with an infectious disease expert warning the disease is "back with a vengeance".
In Queensland, which saw more cases of whooping cough than any other state or territory in the last national reporting period, health authorities have recorded 317 cases of the highly infectious respiratory disease this year — four times the year-to-date average since 2018.
Briannah Quintas's three-month-old daughter, Daisy, was rushed to Gold Coast University Hospital (GCUH) with a severe whooping cough infection in October, despite the entire family being immunised against the disease.
"She was completely blue — completely blue and had stopped breathing," Ms Quintas said.
Ms Quintas said she was on the phone to emergency services when Daisy again stopped breathing moments later.
"She turned blue again and they rushed someone out, put her on a gurney and went in to GCUH, where she had another episode of going blue," she said.
"It was terrifying."
Nationally, 2,542 cases of whooping cough – also called pertussis – were recorded in the 12 months to January 7 this year, but more than 1,000 of those were recorded in the last six weeks of that period.
More cases likely
Director of infectious diseases and immunology at Griffith University, Nigel McMillan, said the recent rise in whooping cough could in part be attributed to a lack of immunity brought about by COVID-19 pandemic isolation.
"We hardly saw any pertussis while we were in COVID isolation but it's come back with a vengeance," Professor McMillan said.
"We seem to be suffering this long-term immune-deficiency where we're just seeing these cases rise."
Experts last year warned Australia was "well overdue" for an outbreak of whooping cough, which Professor McMillan said we could now be seeing the beginnings of.
"A lot of respiratory diseases are being affected by our COVID pandemic isolation, and are coming back now," he said.
"If that coincides with a wave of whooping cough around the world then we are going to see more and more cases because we are a very mobile society."
He said the spike in pertussis cases during the warmer months is unusual as respiratory infections more commonly increase during winter when people gather indoors.
Schools and parents warned
Health authorities on the Gold and Sunshine coasts this week issued public health alerts to schools, parents and GPs, due to the sharp increase in cases of whooping cough.
Dr Nick Smoll from the Sunshine Coast Public Health Unit said the high rates of whooping cough had been exacerbated by the return of school.
"We're noticing this often in school-aged kids, but we are also noticing this all across the Sunshine Coast, both in adults and children," Dr Smoll said.
Gold Coast Public Health doctor Candice Colbran said that, as demonstrated by Daisy's case, babies under six months old were most at risk from a whooping cough infection.
But, Dr Colbran said, most cases on the Gold Coast were in school-aged children.
"It's children aged between five and 17 years of age that are having the illness and getting tested," she said.
"Unfortunately, they're the population that might be spreading it to other people in the community."
Keys to prevention
Whooping cough vaccines are provided free to children up to the age of four as part of the National Immunisation Program.
As of 2021, more than 95 per cent of five-year-old children in Australia were fully vaccinated, including against whooping cough.
Vaccines are also offered free to adolescents aged 12 to 13 through school immunisation programs, and to pregnant women.
Professor McMillan said the number of women who receive the whooping cough vaccine while pregnant is well below the ideal level.
"Those rates are at about 70 per cent, so we could probably improve that," he said.
Dr Colbran said while vaccination against pertussis is key to preventing severe illness, it does not stop mild cases or transmission of the bacteria.
She said in the midst of an outbreak it is important for unwell children to stay away from others.
"Keep them at home, keep them away from school and see a doctor to get them tested," she said.
Ms Quintas, who believes one of her older children inadvertently brought whooping cough home from school, strongly agrees.
"I don't think people realise that sending your kids to school when they're sick can really affect others," she said.
"It puts a really big strain [on the family], plus you don't ever want to see your kid turning blue."