What's causing the recent rise in whooping cough cases in Australia, and who is vulnerable?

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Whooping cough, also known as pertussis, is a persistent concern in Australia, with outbreaks expected every three to four years. Nevertheless, the recent spike that began in 2024 exceeds typical epidemic levels.

Australia has long relied on vaccines to combat this highly contagious respiratory disease. Despite this, controlling it remains difficult due to the gradual decrease in immunity over time, whether gained from previous infections or vaccinations.

By 2025, over 14,000 cases have already been documented. Certain areas, notably Queensland and the Kimberley region in Western Australia, are experiencing significant increases in case numbers.

In 2024, Australia witnessed more than 57,000 whooping cough cases — the highest annual count since 1991 — with 25,900 reports in New South Wales alone.

What is causing the current surge?

A few factors are driving numbers higher than we’d expect for an anticipated epidemic.

COVID lockdowns in 2020 and 2021 reduced natural immunity to many diseases, disrupted routine childhood vaccination services, and resulted in rising distrust in vaccines. This has meant higher-than-usual numbers for many infectious diseases.

And it’s not only Australia witnessing this surge.

In the United States, whooping cough cases are at their highest since 1948, with deaths reported in several states, including two infants.

In Australia, vaccine coverage remains relatively high but it is slipping and is below the national target of 95 per cent.

Even small declines may have a significant impact on infection rates.

Who is at risk of whooping cough?

Young babies, especially those under six weeks of age, are extremely vulnerable to whooping cough because they’re too young to be vaccinated.

Infants under six months of age are also more likely to require hospitalisation for breathing support or have severe outcomes such as pneumonia, seizures or brain inflammation. Some do not survive.

However, the majority of cases are seen in older children and adults. Notably, in 2024, over 70 percent of the cases were among those aged 10 and above, including adults.

Can you get whooping cough even if you’re vaccinated?

The whooping cough vaccine works well, but its protection fades with time. Babies are immunised at six weeks, four months and six months, which gives good protection against severe illness.

But without extra (booster) doses, that protection drops, falling to less than 50 per cent by four years of age. That’s why booster doses at 18 months and four years are essential for maintaining protection against the disease.

A whooping cough vaccine is also recommended for any adult who wishes to reduce the likelihood of becoming ill with pertussis. Carers of young infants, in particular, should have a booster dose if they’ve not received one in the past ten years.

A booster dose is also recommended every ten years for health-care workers and early childhood educators.

The whooping cough vaccine works well, but its protection fades with time. Source: AAP / PA/Alamy

One of the best ways we can protect babies from the life-threatening illness of whooping cough is vaccination during pregnancy, which transfers protective antibodies to the unborn baby.

If a woman has not been vaccinated during pregnancy, it is recommended to administer the vaccine as soon after childbirth as possible, preferably before leaving the hospital. While this does not confer direct immunity to the baby, it reduces the chances of the mother contracting whooping cough, thereby providing some indirect protection to the newborn.

How contagious is whooping cough?

Whooping cough is extremely contagious — in fact, it is up to ten times more contagious than the flu.

If you’re immunised against whooping cough, you’re likely to have milder symptoms. But you can still catch and spread it, including to babies who have not yet been immunised.

Data shows siblings (and not parents) are one of the most common sources of whooping cough infection in babies.

This highlights the importance of on-time vaccination not just during pregnancy, but also in siblings and other close contacts.

How do I know it’s whooping cough, and not just a cold?

Early symptoms of whooping cough can look just like a cold: a runny nose, mild fever, and a persistent cough.

After about a week, the cough often worsens, coming in long fits that may end with a sharp “whoop” as the person gasps for breath.

In very young babies, there may be no whoop at all. They might briefly stop breathing (called an “apnoea”) or turn blue.

In teens and adults, the only sign may be a stubborn cough (the so-called “100-day” cough) that won’t go away.

If you have whooping cough, you may be infectious for up to three weeks after symptoms begin, unless treated with antibiotics (which can shorten this to five days).

You’ll need to stay home from work, school or childcare during this time to help protect others.

What should I do to reduce my risk?

Start by checking your vaccination record. This can be done through the myGov website, the Express Plus Medicare app or by asking your GP.

If you’re pregnant, get a whooping cough booster in your second trimester. A booster is also important if you’re planning to care for young infants or meet a newborn.

Got a cough that lasts more than a week or comes in fits? Ask your GP about testing.

One quick booster could help stop the next outbreak from reaching you or your loved ones.

Niall Johnston is a conjoint associate lecturer at Faculty of Medicine, UNSW Sydney.

Helen Quinn is a senior research fellow at National Centre for Immunisation Research and Surveillance, and a senior lecturer at Children’s Hospital Westmead Clinical School, University of Sydney.

Phoebe Williams is a paediatrician and infectious diseases physician, and a senior lecturer and NHMRC fellow, Faculty of Medicine, University of Sydney.