Chlamydia retesting remains low among young women in Australia: an observational study using sentinel surveillance data, 2018-2022.

BACKGROUND: Chlamydia remains the most notified bacterial sexually transmissible infection in Australia with guidelines recommending testing for re-infection at 3months post treatment. This paper aimed to determine chlamydia retesting and repeat positivity rates within 2-4months among young women in Australia, and to evaluate what factors increase or decrease the likelihood of retesting. METHODS: Chlamydia retesting rates among 16-29-year-old women were analysed from Australian Collaboration for Coordinated Enhanced Sentinel Surveillance of sexually transmissible infection and bloodborne virus (ACCESS) sentinel surveillance data (n =62 sites). Among women with at least one positive test between 1 January 2018 and 31 August 2022, retesting counts and proportions within 2-4months were calculated. Logistic regression was performed to assess factors associated with retesting within 2-4months. RESULTS: Among 8758 women who were positive before 31 August 2022 to allow time for follow up, 1423 (16.2%) were retested within 2-4months, of whom 179 (12.6%) tested positive. The odds of retesting within 2-4months were 25% lower if tested in a coronavirus disease 2019 (COVID-9) pandemic year (2020-2022) (aOR=0.75; 95% CI 0.59-0.95). Among 9140 women with a positive test before 30 November 2022, 397 (4.3%) were retested too early (within 7days to 1month) and 81 (20.4%) of those were positive. CONCLUSIONS: Chlamydia retesting rates remain low with around a sixth of women retested within 2-4months in line with guidelines. Re-infection is common with around one in eight retesting positive. An increase in retesting is required to reduce the risk of reproductive complications and onward transmission.

Determining reinfection rates by hepatitis C testing interval among key populations: A systematic review and meta-analysis.

BACKGROUND & AIMS: Detecting hepatitis C virus (HCV) reinfection among key populations helps prevent ongoing transmission. This systematic review aims to determine the association between different testing intervals during post-SVR follow-up on the detection of HCV reinfection among highest risk populations. METHODS: We searched electronic databases between January 2014 and February 2023 for studies that tested individuals at risk for HCV reinfection at discrete testing intervals and reported HCV reinfection incidence among key populations. Pooled estimates of reinfection incidence were calculated by population and testing frequency using random-effects meta-analysis. RESULTS: Forty-one single-armed observational studies (9453 individuals) were included. Thirty-eight studies (8931 individuals) reported HCV reinfection incidence rate and were included in meta-analyses. The overall pooled estimate of HCV reinfection incidence rate was 4.13 per 100 per person-years (py) (95% confidence interval [CI]: 3.45-4.81). The pooled incidence estimate among people who inject drugs (PWID) was 2.84 per 100 py (95% CI: 2.19-3.50), among men who have sex with men (MSM) 7.37 per 100 py (95% CI: 5.09-9.65) and among people in custodial settings 7.23 per 100 py (95% CI: 2.13-16.59). The pooled incidence estimate for studies reporting a testing interval of ≤6 months (4.26 per 100 py; 95% CI: 2.86-5.65) was higher than studies reporting testing intervals >6 months (5.19 per 100 py; 95% CI: 3.92-6.46). CONCLUSIONS: HCV reinfection incidence was highest in studies of MSM and did not appear to change with retesting interval. Shorter testing intervals are likely to identify more reinfections, help prevent onward transmission where treatment is available and enable progress towards global HCV elimination, but additional comparative studies are required.

Immediate treatment for recent hepatitis C infection in people with high-risk behaviors: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Direct-acting antivirals (DAAs) are almost exclusively approved for the treatment of chronic HCV. This poses a significant barrier to the treatment of recently acquired HCV because of the limited access to DAAs. This review seeks to address this issue by synthesizing evidence of the benefits and harms of immediate treatment after the detection of recently acquired HCV in people at higher risk of infection. APPROACH AND RESULTS: A systematic review and meta-analysis were conducted reporting on populations with recently acquired HCV at higher risk of infection. Studies were included if they assessed standard duration DAA treatment regimens and reported on the benefits and harms of immediate treatment (within one year of diagnosis). Outcomes included sustained virological response at 12 weeks post-treatment (SVR12), incidence, treatment initiation and adherence, overtreatment, engagement in care, and adverse events. Eight cohort studies, 3 open-label trials, and 1 case series study were included, reporting on 2085 participants with recently acquired HCV infection. No studies included a comparison group. Eight studies assessed DAA treatment in either men who have sex with men or men who have sex with men with HIV, 2 studies assessed treatment in people who inject drugs, and 2 among people living with HIV. Immediate treatment of HCV was associated with a pooled SVR12 of 95.9% (95% CI, 92.6%-99.3%). Three studies reported on hepatitis C incidence, where most participants were treated in the chronic phase of infection. A treatment completion rate of 100% was reported in 2 studies, and only 1 serious adverse event was described. CONCLUSIONS: High rates of cure were achieved with the treatment of recently acquired hepatitis C in people at higher risk of infection. Serious adverse events were rare, highlighting individual benefits consistent with the treatment of chronic hepatitis C. The impact of immediate treatment on HCV incidence requires further evaluation.