Australia is struggling with the worst whooping cough epidemic on record since vaccines were introduced to protect against the pertussis bacteria.

As of Friday, November 8, there have been 41,772 confirmed cases of whooping cough in Australia for the year. If projections are accurate, and Australia end up with around 45,000 for the year, it means the rate of infection will have slowed.

In 2023, there were just 2454 notifications of whooping cough for the year.

Adrian Esterman is Professor of Biostatistics at the University of South Australia. He told The New Daily that “the epidemic probably peaked in September”.

But whooping cough is known to have a cyclical outbreak every three to five years. And, as Esterman noted, these outbreaks occur over a two-year period, so cases will likely pick up again.

The respiratory disease is potentially lethal for babies aged under six months, when they are too young to be fully immunised.

Downturn in vaccinations

Infectious disease experts have made repeated appeals throughout the year for parents to get their school-age children vaccinated.

To some extent, via laxness or willful refusal, those calls have gone unheard – with the epidemic driven in large part by schoolchildren and teenagers not getting their boosters in time.

But adults – parents, grandparents and childcare workers –  also need to get a booster shot when they are exposed to small babies.

Most babies become infected when exposed to adults whose whooping cough immunity from a childhood vaccination has waned.

Meanwhile, overall vaccination rates among children in Australia have declined for the third consecutive year, according to the National Centre for Immunisation Research and Surveillance.

The declines tend to be a fraction of a per cent – but the net result is that the government’s plan to get 95 per cent of children vaccinated is going backwards.

According to analysis by the Sydney Morning Herald:

• Of the 13-year-olds due for their pertussis booster last year, one in four didn’t get it
•  The proportion of four-month-old babies getting their second dose on time (within 30 days of the recommended age) dropped by almost seven percentage points (90.1 per cent to 83.5 per cent) between 2020 and 2023.

Complicating the issue are suspicions by researchers that we’re dealing with a newer strain of the Bordetella pertussis bacteria that causes the disease – one that is better at evading the vaccine. This, too, could be driving the rise in cases.

What is whooping cough?

According to the Royal Children’s Hospital in Melbourne:

‘‘Whooping cough is a respiratory infection of the lungs that causes coughing. The coughing can occur in long spells, and often ends with a high-pitched ‘whoop’ sound when the child breathes in.

‘‘Whooping cough is extremely contagious. It is particularly serious in babies under six months of age, who are at risk of severe complications and will usually need to be admitted to hospital.

‘‘Whooping cough is spread easily by droplets of fluid in the air from coughing and sneezing. It can also be spread by hands that have come in contact with the bacteria.

‘‘If your child has whooping cough, they will be infectious just before the start of the cough until three weeks after the cough started. If your child is given antibiotics, they can still spread the infection until they have had five days of antibiotics.

‘‘Because whooping cough is easily spread, often other family members or close contacts of the child with whooping cough will also have the infection.’’

Signs and symptoms of whooping cough

Whooping cough usually starts with cold-like symptoms, such as a runny nose and dry cough, which last for about one week.

After that, a more definite cough develops, which may last for 10 weeks or more.

Some children cough so much they vomit afterwards.

Children are usually well between coughing spells.

Babies under six months of age may have pauses in breathing, or apnoeas, instead of a cough.

In more severe cases, babies and children may have problems catching their breath after a coughing spell.

Caring for a sick child

In most cases, children with whooping cough can be cared for at home after they have been seen by a doctor.

Give your child small, frequent meals and fluids often (such as sips of water or smaller feeds, but more often).

Taking care of a child with whooping cough can be stressful. Ask for help from family and friends so that you can catch up with sleep.

The antibiotic usually prescribed for whooping cough is Azithromycin. It’s used to treat infections including chest infections such as pneumonia, and ear, nose and throat infections such as sinus infections.

At the moment, according to the TGA, none will become available until early 2025. Alternatives are available.