Improving public health surveillance of chlamydia: analysis of population-level positivity trends

Background: Chlamydia remains Australia's most frequently notified communicable disease; however, interpretation of notification data is difficult without knowledge of testing practices. This study examined the value of reporting positivity trends.

Methods: Tasmanian population-level chlamydia laboratory tests and notification data from 2001 to 2010 were compared.

Results: Notifications, tests and positivity increased, most significantly in males and females aged 15-29 years.

Conclusions: Analysis of chlamydia positivity trends can inform the development, monitoring and evaluation of prevention and control activities and improves the interpretation of notification trends. After allowing for testing effort, an increase in chlamydia infections in young people was found.