Gonococcal infections and risk factors for reinfection: a descriptive and case-case analysis of notifications in the Australian Capital Territory, 2017-2022

Abstract

Background: In Australia, gonococcal infection notification rates are increasing with reinfections representing a substantial proportion of infections. Understanding the local epidemiology of gonococcal infections and reinfections and the risk factors for reinfection can assist with the design of targeted interventions. This study aimed to describe the epidemiology of gonococcal infections and reinfections between 2017 and 2022 in the Australian Capital Territory (ACT), and to examine the risk factors for reinfection.

Methods: Data for gonococcal infections notified in the ACT between 2017 and 2022 were described. The epidemiological characteristics of individuals with a single infection and reinfection were compared using a case-case study design.

Results: There were 1,886 gonococcal infection notifications during the study period. Of these, 20.4% were reinfections (n = 385). Of 1,501 individuals, 1,254 (83.5%) had a single infection and 247 (16.5%) had a reinfection. Between 2017 and 2022, the annual gonococcal infection notification rate per 100,000 population increased from 59.98 to 80.14 and the proportion of reinfections from 4.0% to 26.8%. Compared with those with a single infection, individuals with a reinfection had significantly greater odds of being male, of having a same-sex sexual exposure, of using HIV pre-exposure prophylaxis at diagnosis, and of having been diagnosed at a sexual health/family planning clinic. Individuals with a reinfection had significantly greater odds of being in the 25-34, 35-44 and 45-54 years age groups than in the 14-24 years age group. The odds of anatomical site of first infection being only the rectum, only the throat, or at more than one site, compared with urogenital only, were significantly greater for those with a reinfection.

Conclusion: Gonococcal reinfections contribute substantially to gonococcal infection notifications in the ACT. Targeted interventions are needed to prevent gonococcal reinfections among at-risk groups, particularly among men who have sex with men, people who use HIV pre-exposure prophylaxis, and individuals accessing sexual health/family planning services.

Keywords: Australian Capital Territory; gonococcal infection; notifications; reinfection; risk factor; sexually transmissible infection.