Population-level diagnosis and care cascade for chlamydia in Australia

Richard T. Gray*, Denton Callander, Jane S. Hocking, Skye McGregor, Hamish McManus, Amalie Dyda, Clarissa Moreira, Sabine Braat, Belinda Hengel, James Ward, David P. Wilson, Basil Donovan, John M. Kaldor, Rebecca J. Guy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Objectives: Key strategies to control chlamydia include testing, treatment, partner management and re-testing. We developed a diagnosis and care cascade for chlamydia to highlight gaps in control strategies nationally and to inform efforts to optimise control programmes. Methods: The Australian Chlamydia Cascade was organised into four steps: (1) annual number of new chlamydia infections (including re-infections); (2) annual number of chlamydia diagnoses; (3) annual number of diagnoses treated; (4) annual number of diagnoses followed by a re-test for chlamydia within 42-180 days of diagnosis. For 2016, we estimated the number of infections among young men and women aged 15-29 years in each of these steps using a combination of mathematical modelling, national notification data, sentinel surveillance data and previous research studies. Results: Among young people in Australia, there were an estimated 248 580 (range, 240 690-256 470) new chlamydia infections in 2016 (96 470 in women; 152 100 in men) of which 70 164 were diagnosed (28.2% overall: women 43.4%, men 18.6%). Of the chlamydia infections diagnosed, 65 490 (range, 59 640-70 160) were treated (93.3% across all populations), but only 11 330 (range, 7660-16 285) diagnoses were followed by a re-test within 42-180 days (17.3% overall: women 20.6%, men 12.5%) of diagnosis. Conclusions: The greatest gaps in the Australian Chlamydia Cascade for young people were in the diagnosis and re-testing steps, with 72% of infections undiagnosed and 83% of those diagnosed not re-tested: both were especially low among men. Treatment rates were also lower than recommended by guidelines. Our cascade highlights the need for enhanced strategies to improve treatment and re-testing coverage such as short message service reminders, point-of-care and postal test kits.

Original languageEnglish
Pages (from-to)131-136
Number of pages6
JournalSexually Transmitted Infections
Issue number2
Early online date5 Jun 2019
Publication statusPublished - Mar 2020
Externally publishedYes


  • care cascade
  • control
  • genital chlamydia trachomatis
  • high-income setting
  • incidence
  • sti guidelines
  • surveillance and monitoring


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