Australia is on the brink of a whooping cough epidemic, with cases skyrocketing to 11,000 in the first half of 2024. This marks a significant increase compared to the 2,447 cases recorded throughout all of last year, setting the stage for the worst outbreak since 2016.
Epidemic Cycles and Strain Evolution
Whooping cough, or pertussis, is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. It follows epidemic cycles that can vary in severity depending on the bacterial strain. Recent surges indicate that Australia could face a substantial epidemic this year.
Symptoms and Vulnerable Populations
The disease typically begins with symptoms resembling a common cold—runny nose, sneezing, mild cough, and fever. However, within one to two weeks, severe coughing fits can develop, sometimes leading to vomiting or fractured ribs. Known as the “100-day cough,” pertussis can persist for up to three months.
“Whooping cough is particularly perilous for infants under six months old, who are too young to be vaccinated,” explained Dr. Laurence Luu, a microbiologist at the University of Technology Sydney. “The disease can cause newborns to stop breathing and turn blue.”
Testing and Early Detection
Due to its highly contagious nature, early testing is crucial. “Adults may not exhibit the characteristic ‘whoop’ sound, making diagnosis challenging,” Dr. Luu noted. “Early antibiotic treatment can mitigate the severity, but timely detection is key.”
Hospitalization and Mortality Rates
According to the Australian Institute of Health and Welfare, approximately one in three infants under 12 months with whooping cough requires hospitalization. In severe cases, the disease can lead to pneumonia, brain damage, and even death, with one in 125 affected infants succumbing to complications. 
Outbreak Cycles and COVID-19 Impact
Dr. Luu highlighted the cyclical nature of whooping cough outbreaks, which typically occur every three to four years. “The last major spike was around 2017. The expected resurgence in 2020 was delayed by COVID-19, leading to the current surge.”
Australia’s largest recorded outbreak followed the widespread introduction of vaccines, with over 140,000 cases between 2008 and 2012, peaking at nearly 40,000 cases in 2011. “We are witnessing a similar pattern now,” stated Dr. Peter Richmond, head of paediatrics at the University of Western Australia.
Geographical Spread and Demographic Trends
The National Notifiable Disease Surveillance System reports that Queensland and New South Wales have seen the highest increases in cases, with numbers also rising in Victoria and other states. “This surge began in late 2023 and has particularly affected school-aged children,” Professor Richmond observed.
Missed routine vaccinations during the pandemic may have left certain groups more susceptible. “Children should receive six doses of the whooping cough vaccine between six weeks and 13 years old,” Richmond emphasized. “Timely vaccination is critical.”
Global Trends and New Strains
Australia is not alone in facing a whooping cough resurgence. The United States, United Kingdom, Europe, and China have also reported significant increases. China, in particular, saw over 30,000 cases in the first two months of 2024, nearly matching the total for the previous year. “New antibiotic-resistant strains have emerged,” Dr. Luu cautioned.
Research conducted with the University of New South Wales in 2020 identified a new strain in Australia that emerged during the 2008 epidemic. This strain could evade vaccines more effectively, suggesting the need for advanced vaccination strategies.
Current and Future Vaccination Strategies
Despite the challenges, current vaccines remain effective. “We are working on new vaccines that offer longer-term immunity and reduce transmission,” said Professor Richmond, who is developing a nasal spray vaccine with the Telethon Kids Institute.
Vaccination Recommendations
- Infants and Children: A 5-dose schedule at 2, 4, 6, and 18 months, and at 4 years of age.
- Adolescents: A booster around 11-13 years.
- Adults: A booster every 10 years.
- Pregnant Women: A single dose between 20-32 weeks of pregnancy.
Healthcare workers, early childhood educators, and carers should receive boosters every 10 years.
Conclusion
With the current resurgence, ensuring up-to-date vaccinations is imperative. Pregnant women, the elderly, and those in regular contact with infants are particularly urged to get vaccinated. “Pertussis is not going away,” Professor Richmond concluded. “This resurgence underscores the importance of maintaining vaccination schedules.”
