Footnotes

• Handling editor Anna Maria Geretti

• Contributors ZK conceptualised and implemented the overall study design, implemented the epidemiological methods. AA led interpretation of analyses, drafted the manuscript, and provided epidemiological and writing support on the manuscript. JS provided clinical expertise in sexual health medicine, interpretation of analyses and writing support on the manuscript. PD provided technical expertise in epidemiological methods and provided support in writing support the manuscript. CET contributed to the conceptual and technical support early in the study design phase of the project, and provided epidemiological and writing support on the manuscript. TW provided clinical expertise in infectious diseases, interpretation of analyses and writing support on the manuscript.

• Funding This work was supported by funds from the New Zealand Ministry of Health STI Surveillance.

• Competing interests None declared.

• Provenance and peer review Not commissioned; internally peer reviewed.

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