BackgroundHuman papillomavirus (HPV) infection, a common sexually transmitted disease, is associated with cancers of the cervix, vulva, vagina, penis, anus, and head and neck. Oropharyngeal squamous cell carcinoma (OPSCC; throat cancer) is a type of cancer involving the head and neck area that is rapidly increasing across the globe. There are higher rates of OPSCC among Indigenous populations relative to non–Indigenous Australian populations, although the HPV-attributable fraction remains unknown. For the first time at a global level, we plan to extend an Indigenous Australian adult cohort to monitor, screen, and ultimately prevent HPV-associated OPSCC and to undertake extensive cost-effectiveness modelling around HPV vaccination.ObjectiveThis study aims to (1) extend follow-up to a minimum of 7 years post recruitment to describe the prevalence, incidence, clearance, and persistence of oral HPV infection; and (2) conduct clinical examinations of the head and neck, oral cavity, and oropharynx and collect saliva samples for early-stage OPSCC testing.MethodsWe will continue to implement a longitudinal design for the next study phase, where we will ascertain the prevalence, incidence, clearance, and persistence of oral HPV infection at 48, 60, and 72 months; undertake clinical examinations/saliva assessments to detect early-stage OPSCC; and refer for treatment. The primary outcome measures are changes in oral HPV infection status, biomarker measures of early HPV-related cancer, and clinical evidence of early-stage OPSCC.ResultsParticipant 48-month follow-up will commence in January 2023. The first results are expected to be submitted for publication 1 year after 48-month follow-up begins.ConclusionsOur findings have potential to change the way in which OPSCC among Australian Indigenous adults is managed, with desired impacts including cost-savings on expensive cancer treatments; improved nutritional, social, and emotional outcomes; and improved quality of life for both Indigenous adults and the Indigenous community more broadly. Continuing a large, representative Indigenous adult cohort to track oral HPV infection and monitor early OPSCC is essential to yield critical information to include in the management armamentarium of health and well-being recommendations for Australia’s First Nations.International Registered Report Identifier (IRRID)PRR1-10.2196/44593