Contact tracing for sexually transmitted infections in Aotearoa New Zealand: a review of clinician-notified gonorrhoea and syphilis data

Introduction The sexually transmitted infections (STIs) gonorrhoea and syphilis became notifiable in Aotearoa New Zealand in 2017, requiring diagnosing clinicians to complete an anonymous case report form detailing behavioural, clinical and management information. Surveillance for gonorrhoea occurs through laboratory and clinician notification, whereas syphilis is only clinician-notified. Aim To review information related to contact tracing (partner notification) from routinely collected gonorrhoea and syphilis notification data. Methods Aggregated data on clinician-notified gonorrhoea and syphilis cases in 2019 were analysed to review information related to contact tracing and to estimate numbers of partners requiring contact tracing. Results There were 722 cases of syphilis and 3138 cases of gonorrhoea notified by clinicians in 2019. However, there were 7200 laboratory-notified gonorrhoea cases, so clinician notification occurred for less than half (43.6%, 3138/7200) of the cases, ranging from 10.0 to 61.5% across District Health Board regions. An estimated 28 080 recent contacts of gonorrhoea cases and 2744 contacts of syphilis cases would have required contact tracing in 2019. Contact tracing could not be completed for 20% of syphilis and 16% of gonorrhoea cases due to anonymous contacts, and was 'initiated or planned' for 81% of gonorrhoea cases and 79% of syphilis cases. Discussion Although surveillance data for gonorrhoea and syphilis are incomplete, estimates can be obtained about the number and type of contacts, which can be used to inform contact tracing strategies. Optimisation of the content of clinician-completed forms and an improved response rate would provide a more complete picture to inform interventions to address the high and inequitable prevalence of sexually transmitted infections in Aotearoa New Zealand.