Primary HIV-1 drug resistance in Canada:

1. Primary HIV-1 drug resistance in Canada: Updated results from the Canadian HIV Strain and Drug Resistance Surveillance Program Canadian HIV Strain and Drug Resistance Surveillance Program XVI International AIDS Conference Toronto August 13-18

2. Canadian HIV SDR Program Partners and Contributing Authors PHAC BC AB Chris Archibald Michael Rekart Ameeta Singh Gaya Jayaraman Jutta Preiksaitis Neil Goedhuis SK Paul Sandstrom Huiming Yang MB James Brooks Fred Sidaway Magdy Dawood Harriet Merks Greg Hammond ON NS Robert Remis NL Maureen Baikie Carole Swantee Sam Ratnam Faith Stratton

3. Acknowledgments • Field Surveillance Officers, PHAC Elsie Wong (BC) Sabrina Plitt (AB) Erin Laing (SK) Michelyn Woods (MB) Lena Shah (ON) Tracey MacDonald (NS) • HIV Surveillance Section, PHAC Jennifer Pennock Jennifer Geduld Chris Sheardown Stéphane Racette

4. Objectives • To describe the prevalence of primary drug resistance in Canada and associated trends (1998-2005) • To describe the factors associated with primary drug resistance

5. Background – HIV Drug Resistance • Drug resistance among untreated individuals (primary DR) is presumably due to transmission of a drug resistant strain of HIV from a treated individual • Prior to the Canadian HIV SDR program no systematic surveillance for primary DR across Canada

6. Program Description • Comprises all individuals newly diagnosed with HIV in Canada for whom left-over diagnostic serum samples are available for subtype and DR genotyping. • No subjects are directly recruited • Only treatment-naïve individuals are included

7. SDR Surveillance Program- Participating Provinces NL BC AB MB SK ON NS

8. Data Collection and Transfer National HIV Laboratories Epidemiological data => Routine + Enhanced Serum specimens subtype data P/T Partners PHAC primary DR mutations “detuned” assay data Laboratory results plus Epidemiological data SRAD

9. Distribution of Primary DR 1998-2005 N = 2,333

10. Mutations Associated with DR PI NNRTI NRTI

11. Proportion of cases with primary DR (overall), 1998-2005 p=0.056

12. Proportion of cases with resistance to NNRTI 1998-2005 p=0.003 Proportion with Drug Resistance (%)

13. Factors associated with primary DR

14. Factors associated with primary DR, con’t

15. Published August, 2006 (contains data to March 2005) • Data from SDR program generate research questions and used for other specific analyses August 2006

16. Program Limitations • Data only include individuals who were infected and diagnosed with HIV. • Results based on number of newly diagnosed cases with sufficient sera for whom PCR amplification was successful. • Treatment history cannot always be verified. • Current assays may not accurately identify recent infections particularly among the non-B subtypes.

17. Conclusions • Prevalence of primary DR in sample 9.1%. • Overall prevalence of primary DR may be increasing over time; accounted for mainly by an increase in the prevalence of NNRTIs. • No significant differences found by sex, age at diagnosis or across exposure category • Higher proportion of primary drug resistance found among: • Recent infections • Ethnicities other than African/Caribbean • B subtypes

18. Next Steps • Increase coverage across Canada to increase representativeness, sample size and power • Liaise with national stakeholders to inform prevention and treatment programs and policies • Partner with national and international experts to develop list of mutations to be used for DR surveillance in B and non-B subtypes • Partner with international experts to monitor global trends