Chlamydia trachomatis and Neisseria gonorrhoeae retesting and reinfection rates in New Zealand healthcare settings: implications for STI control

BACKGROUND: Reinfection with chlamydia or gonorrhea is common and can lead to significant reproductive health complications so testing for reinfection after treatment is recommended. This study described retesting and reinfection rates in regions of New Zealand with higher-than-average population rates of chlamydia. METHODS: This retrospective cohort study analyzed chlamydia and gonorrhea testing data from 2 laboratories providing community testing services for 4 higher-rate regions in the North Island of New Zealand. Three years of data were obtained (2015-2017) to include a minimum of 6-month follow-up for all individuals. Retesting and reinfection rates between 6 weeks and 6 months of a positive result were calculated, and time to retesting was plotted using Kaplan-Meier curves. Logistic regression modeling was used to determine the odds of retesting (outcome 1) and reinfection (outcome 2) between 6 weeks and 6 months of follow-up. RESULTS: Overall, 34% (3151/9241) of the cohort was retested within the recommended period, of whom 21% retested positive. Significant differences were observed in the odds of retesting by sex, age band, ethnic group, clinic type, and region (P < 0.01). The odds of a subsequent positive on retesting within 6 months differed significantly by sex, age band, and ethnic group (P < 0.01). CONCLUSIONS: These findings reflect substantial gaps in the delivery of best-practice sexually transmitted infection management in New Zealand. There is a clear need to prioritize the implementation of clinic-level processes to support clinicians in the routine delivery of best-practice sexual health care. These should include routine provision of patient advice about retesting and strategies to promote timely and equitable access to retesting.