Estimating pertussis incidence in general practice using a large Australian primary care database.

Area of Science:

• Epidemiology
• Public Health
• Infectious Diseases

Background:

• Pertussis (whooping cough) is a notifiable disease, but official notifications often underestimate its true incidence.
• Understanding the actual burden of pertussis in primary care settings is crucial for effective public health strategies.

Purpose of the Study:

• To explore and estimate the incidence of pertussis-related encounters in Australian general practice.
• To compare primary care-based pertussis incidence with national notification data.

Main Methods:

• Utilized MedicineInsight, a large electronic medical record database (>1.5 million patients).
• Defined four categories of pertussis-related encounters using free-text search algorithms.
• Calculated incident pertussis-related encounter rates per 100,000 active patients from 2008 to 2015.

Main Results:

• Estimated mean annual pertussis incidence ranged from 94.3 (category 1) to 148.8 (categories 1+2+3) per 100,000 patients.
• Incidence was highest in children aged 0-9 years and 30% higher in females.
• Combined categories 1-3 showed an incidence 64% higher than national pertussis notification rates.

Conclusions:

• Primary care data reveals a significantly higher burden of medically-attended pertussis than previously indicated by notification rates.
• MedicineInsight data offers valuable insights into the epidemiology of pertussis.
• Findings underscore the limitations of current pertussis surveillance systems.