Indigenous Australian HPV Cohort Study

This prospective longitudinal cohort study was developed in partnership with Indigenous communities in SA and is governed by an Indigenous Reference Group, with data collected by trained Indigenous research officers.

The study, funded by the NHMRC in 2016, is led by Senior Aboriginal Research Officer Joanne Hedges. Funding for follow-up at 48, 60 and 72 months has been obtained from the NHMRC.

Participants

To be eligible at baseline, participants needed to identify as being Aboriginal and/or Torres Strait Islander, aged 18+ years and residing in SA. Participants were recruited from Feb 2018 to Jan 2019 across 8 SA sites, primarily through ACCHOs whose CEOs are key stakeholders. There was strong buy-in from the Indigenous community during recruitment, with several participants contacting the principal investigator by phone asking what they needed to do to be involved. The 1,011 participants recruited represent 5.0% of Indigenous SA adults eligible during the recruitment period; 8.2% of those eligible in non-metropolitan locations and 3.0% of those in metropolitan locations. Participants were followed-up at 12 months, with data from 749 participants obtained. Follow-up at 24 months resulted in 815 participants.

Progress and findings

Of the 1,011 participants recruited, 910 provided β-globin positive saliva samples (β-globin is a DNA integrity check). Of these 910, 35% were positive for any HPV infection. This was 5 times the prevalence reported in a systematic review involving the US, Brazil, Mexico and Finland.

The most prevalent HPV types at baseline were those associated with Heck’s disease (multifocal epithelial hyperplasia; 23% of the HPV types found); a relatively benign and rare condition caused by oral HPV 13 or 32 that is more prevalent among Indigenous populations. The next most prevalent HPV types were those associated with OPSCC (HPV 16 or 18; 3.3% of the types found).

Of the 749 participants retained at 12-month follow-up, 645 provided β-globin positive saliva samples. Of these, 43% were positive for any HPV infection. The most prevalent HPV types at 12-months were again those associated with Heck’s disease (33% of the HPV types found), followed by HPV types associated with OPSCC (HPV 16 or 18; 2.5%).

A total of 588 participants had samples at baseline and 12-month follow-up that were β-globin positive. The prevalence of any oral HPV infection increased from 34% to 44%. This increase was largely due to increases in HPV types 13 or 32 (Heck’s disease); from 20% at baseline to 34% at 12-months. The prevalence of HPV 16 or 18 decreased from 3.9% at baseline to 2.7% at 12-months. The prevalence of high risk HPV types according to the International Agency for Research on Cancer (IARC) definition decreased from 8.5% at baseline to 7.1% at 12-months.