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 PHACBCAB Chris ArchibaldMichael RekartAmeeta Singh Gaya JayaramanJutta Preiksaitis Neil GoedhuisSK Paul SandstromHuiming YangMB James BrooksFred SidawayMagdy Dawood Harriet MerksGreg Hammond ON NSRobert RemisNL Maureen BaikieCarole SwanteeSam 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 BC AB SK MB NL ON NS

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

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

10. Mutations Associated with DR PI NRTI NNRTI

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

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

13. Variable Sample size % Drug Resistant p value Sex0.329 Male1701 8.8 Female61910.2 Risk Exposure0.951 MSM662 9.4 MSM/IDU71 8.5 IDU637 8.6 Heterosexual685 9.2 Age0.822 15-193613.9 20-29491 9.4 30-39852 9.9 40-49639 8.0 50-59207 8.7 60+83 8.4 Factors associated with primary DR

14. Variable Sample size % Drug Resistant p value Time of Infection0.130 Recent53810.4 Established14218.2 Ethnicity0.052 Aboriginal55011.1 Asian798.9 Caucasian12008.3 African/Caribbean2224.5 Subtype0.012 B20409.7 non-B2885.2 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