Whooping cough cases across Australia have passed 40,000 in a year for the first time since recording began more than 30 years ago.

To November 6, there had been 41,013 cases confirmed across the country, passing the 38,748 cases recorded in 2011.

Surges in cases are expected every five years but doctors and infectious disease experts say they had not anticipated the magnitude of this year's outbreak.

"Australia is currently in the midst of a whooping epidemic that is expected to continue for many months," paediatrician and vaccine expert Professor Nicholas Wood said.

Approximately 130 confirmed cases of whooping cough (pertussis) have been recorded each day on average in 2024, according to data from the National Notifiable Diseases Surveillance System, with more than 45,000 cases of the respiratory infection expected by the end of the year.

New South Wales has recorded the highest number of cases (19,653), followed by Queensland (11,728).

Dr Laurence Luu, Chancellor's Research Fellow and Lecturer at University of Technology Sydney said low vaccination rates are a major concern amid the surge in cases.

"While we do an incredible job protecting newborns and infants, re-vaccination or 'booster' rates are alarmingly low," he said.

Data from the National Centre for Immunisation's annual report shows that in 2023, one-in-four adolescents turning 13 years of age missed out on their whooping cough booster, while only one-in-five Australians aged over 50 years is up to date for whooping cough vaccination.

"The impact on the public's trust in vaccination since the pandemic is affecting the performance of the childhood immunisation program and vaccination coverage rates are below the 95 per cent target required for herd immunity," a spokesperson for the federal Department of Health told the ABC.

Whooping cough, also known as pertussis, is a highly infectious respiratory disease that can be fatal for infants.

It attacks the airways, causing uncontrollable coughing and difficulty breathing.

As symptoms of whooping cough often don't appear for a week or two following infection, the bacteria is easily spread and, once infected, a person can remain contagious for three weeks or until they complete a course of antibiotics.

Typically in adulthood, pregnant women and those around small children are urged to get their booster.

Under the national program, all pregnant women can access the vaccine for free.

Dr Sonia McAlister, a pertussis researcher, said that decades of research showed vaccination was the single most effective way to prevent whooping cough.

"Whooping cough doesn't just affect kids," she said.

"Getting vaccinated on time is the best way to prevent disease."

All Australians urged to be up to date on vaccinations

While not usually fatal for older children and adults, long-term effects of the disease can include broken or sprained ribs, incontinence and weeks of coughing.

New South Wales GP and Royal Australian College of General Practitioners board member Dr Rebekah Hoffman said cases are so high she is advising all of her patients to get their booster.

"It's really worrying from a GP's perspective. At the moment we'd be expecting numbers to drop off from the end of winter and we'd be heading back to normal toward the end of year," she said.

"But what we've seen is people still presenting with cough and viral symptoms and a lot of the time we're really surprised when it comes back as whooping cough when we might have expected it to be something else."

Whooping cough is diagnosed by a swab test at a pathology clinic.

Children aged 10-14 have the highest rates of whooping cough in the country. Dr Hoffman said vaccination rates can tend to drop off within that age group.

"Unfortunately, the last whooping cough vaccine children get is age four and then next is about 13-14 years of age," she said.

"We know you get really good coverage for five years but it then does drop off after that."

Older children who are not vaccinated are often the source of infection for infants.

Protecting infants from infection

Catherine Hughes lost her four-week-old son Riley to whooping cough in 2015.

Riley was three weeks of age when he started displaying cold-like symptoms and developed an occasional cough.

After a night where he barely woke they knew something was wrong and took him to hospital.

It was first suspected he had bronchitis, but quickly the doctors suspected (whooping cough) and began treating him for it.

Despite treatment in a paediatric intensive care unit, he died at just 32 days old.

Ms Hughes, who was not offered a vaccine booster while she was pregnant, went public with her tragedy to encourage the government to consider a free program for expectant mothers.

Her work then evolved into the establishment of the National Immunisation Foundation of Australia.

The foundation has just released its Whooping Cough report card where it highlights the major surge in cases.

Ms Hughes said: "It has been a number of years since the last epidemic and this is an epidemic."

"I just worry we'll see another die."

There have been no infant deaths related to whooping cough since 2019.

From January 1, 2019 to October 27, 2024, there were two deaths in infants aged 0-5 months, which were infected with whooping cough.

Infectious diseases expert Dr Nigel Macmillan said research into the surge in cases needs to be done.

While vaccination rates have dropped off and surges are cyclical he is surprised by the "exceptionally high" numbers of cases.

"I was looking at data in front of me from 2005, 2010, 2015 so honestly it's (surges in cases) like clockwork almost," he said.

"[but] Those numbers of those peaks are much lower than what we're seeing now.

"There's definitely something else going on, we just don't know what it is."

And it is not just happening in Australia.

"The CDC in the US is recording five times the typical amount and the UK is having the same problem," Professor Macmillan said.

"We don't really know what this current set of cases are and if they're caused by bacteria that might have changed and if it is better at avoiding immunity we have."

GPs say there are even more cases in the community going undetected.

"It is… the tip of the iceberg," Dr Rebekah Hoffman, a GP in New South Wales said.

"That is just patients who have gotten their swab done or have been in the emergency department."

Information on how to check your immunisation record can be found here.