Attitudes to and Understanding of Risk of Acquisition of HIV Over Time: Design and Methods for an Internet-based Prospective Cohort Study Among UK Men Who Have Sex With Men (the AURAH2 Study).

Background: The annual number of new human immunodeficiency virus (HIV) infections among men who have sex with men (MSM) has risen in the United Kingdom and, of those who are HIV positive, the proportion undiagnosed is high.

Objective: The prospective AURAH2 study aims to assess factors associated with HIV acquisition among MSM in the United Kingdom and to investigate changes over time within individuals in sexual behavior and HIV-testing practices.

Methods: AURAH2 is a prospective study among MSM without diagnosed HIV, aiming to recruit up to 1000 sexually active MSM attending sexual health clinics in London and Brighton in the United Kingdom.