Epidemiology of notified chlamydia infections, Queensland, 2000-2019.

BACKGROUND

Chlamydia infection is a frequently reported notifiable condition in Queensland, with the highest prevalence observed among young people. Infection can occur in several sites including the anus, eye, pharynx, cervix/vagina, and urethra. Currently, historical trends in chlamydia by site of infection in Queensland are unknown.

METHODS

A descriptive analysis of all chlamydia notifications in Queensland, 2000-2019, was performed. Queensland Health statewide notification data were classified as either anorectal, eye, genitourinary, upper respiratory tract, or other/unspecified. The number of chlamydia tests and proportion of tests positive for chlamydia were calculated using Medicare online testing data. Population denominator values were obtained from the Australian Bureau of Statistic's catalogues.

RESULTS

Over the 20-year period, chlamydia notifications increased, particularly among individuals aged 20-24 years. However, there was a noticeable decline in genitourinary notifications among those aged 15-19 years since 2010. Despite increased testing, the ratio of positive specimens to testing decreased among females aged 15-24 years.

CONCLUSIONS

Across the period of our study, there was a substantial and sustained decline in chlamydia notifications in those aged 15-19 years. Further research is required to understand factors that have contributed to this decrease and to guide programs for controlling chlamydia.