Time since last negative HIV test among men who have sex with men and people who use injection drugs in British Columbia, 2006-2011.

Objectives: Canadian surveys of men who have sex with men (MSM) and people using injection drugs (IDU) demonstrate that most have tested for HIV at least once, but that half or fewer have done so in the previous year. To better inform targeted HIV testing guidelines for these populations, we derived estimates of inter-test interval (ITI) for persons newly diagnosed with HIV in British Columbia (BC) between 2006 and 2011, and assessed variables associated with longer ITI among MSM and IDU.

Methods: Provincial HIV case report and testing data were linked by deterministic and probabilistic matching (based on unique personal health number, name, and date of birth). ITI was defined as time from last recorded negative to first positive HIV result; those with ITI ≤30 days were excluded.

Results: Of 2,004 eligible individuals, 1,116 (55.7%) had a recorded negative HIV test result in the previous ten years. Overall median ITI was 20 months with a skewed distribution (inter-quartile range 8-46); median ITI was 15 months for MSM and 21 months for IDU with 41.2% and 33.1% testing in the past year, respectively. Longer ITI was associated with older age for both groups, and among MSM with residence outside Vancouver and not known to have an HIV-positive partner.

Conclusions: These findings highlight potential missed opportunities for earlier detection of HIV and prevention of secondary transmission among newly diagnosed MSM and IDU, and provide evidence to inform recommendations for HIV test frequency and testing strategies for these populations in BC.