Australia is experiencing a significant and concerning resurgence of whooping cough, with new research pinpointing the primary drivers behind the post-COVID surge. The findings come as health authorities record a sharp increase in cases of the highly contagious respiratory disease, also known as pertussis.
Immunity Gap and Waning Protection Fuel Outbreak
According to the latest analysis, the current spike is largely attributed to an immunity gap created during the COVID-19 pandemic. With prolonged lockdowns, border closures, and social distancing measures, the usual circulation of the Bordetella pertussis bacteria was drastically reduced. This led to a lack of natural boosting of immunity in the community, leaving a larger pool of susceptible individuals.
Compounding this issue is the fact that protection from both the disease and the vaccine diminishes over time. Professor Robert Booy, an infectious diseases expert from the University of Sydney, emphasised that vaccine immunity wanes after five to ten years. This natural decline, combined with the pandemic-induced gap, has created a perfect storm for transmission.
Alarming Case Numbers and High-Risk Groups
Official data reveals a stark picture. In the first half of 2024 alone, Australia recorded more than 11,000 cases of whooping cough. This figure dramatically outpaces the roughly 2,500 cases reported for the entirety of 2023. The surge has been declared a national outbreak by health officials.
The research highlights that infants under six months old are at the greatest risk of severe complications and death, as they are too young to be fully vaccinated. The illness is particularly dangerous for this group, causing severe coughing fits that can lead to pneumonia, brain damage, and even death. Pregnant women, teenagers, and adults with waning immunity are also key carriers who can unknowingly transmit the bacteria to vulnerable babies.
Urgent Call for Vaccination and Boosters
Health experts are issuing a strong and urgent public health message centred on vaccination. The cornerstone of prevention remains the pertussis vaccine, offered free under the National Immunisation Program.
The critical recommendations are:
- Pregnant women should receive a whooping cough booster (dTpa vaccine) during every pregnancy, ideally between 20 and 32 weeks. This provides passive immunity to the newborn in their first vulnerable months.
- Infants and children must receive their scheduled doses at 6 weeks, 4 months, 6 months, 18 months, and 4 years of age.
- Adolescents are due for a booster at around 12-13 years of age.
- Adults, especially those in contact with young infants (parents, grandparents, childcare workers), are urged to check their vaccination status and get a booster if it has been more than ten years since their last dose.
Professor Booy stresses that while the vaccine may not always prevent infection entirely, it is highly effective at preventing severe disease, hospitalisation, and death. He describes the current situation as a "wake-up call" for the nation to review immunisation records and close the immunity gaps that have opened up.
The research underscores that high population vaccination coverage is essential to protect those who are most vulnerable and cannot be vaccinated themselves. As Australia moves through winter and respiratory virus season, health authorities are monitoring the outbreak closely and reinforcing the message that vaccination remains the best defence against this serious and resurgent disease.
