Primary HIV-1 drug resistance in Canada:
description
Transcript of Primary HIV-1 drug resistance in Canada:
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
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
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, PHACJennifer PennockJennifer GeduldChris SheardownStéphane Racette
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
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
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
SDR Surveillance Program-Participating Provinces
BC AB
SK
MB
NL
ONNS
Data Collection and Transfer
P/T Partners
SRAD
PHAC
National HIV Laboratories
Laboratory resultsplus Epidemiological data
Serum specimens
Epidemiological data => Routine + Enhanced
subtype data
primary DR mutations
“detuned” assay data
PI2.1%
NNRTI2.0%NRTI
3.9%
MDR1.1%
WT90.9%
N = 2,333
Distribution of Primary DR1998-2005
0
10
20
30
40
50
60
70
M41
L
T21
5C/D
/E/S
/I/L
L210
W
M18
4V
V11
8I
T21
5Y
T69
D
D67
N
K21
9Q
Q15
1M
A62
V
K65
R
F77
L
V75
I
M18
4I
Y11
5F
F11
6Y
K10
3N
V10
8I
G19
0A
Y18
1C
Y18
8L
G19
0S
P22
5H
L100
I
Y18
1I
M23
0L
P23
6L
L90M
M46
I
M46
L
D30
N
V82
F
I84V
V82
A
G48
V
PI NNRTI NRTI
Nu
mb
er
Ca
se
s w
ith
Mu
tati
on
Mutations Associated with DR
PI NRTINNRTI
Proportion of cases with primary DR (overall), 1998-2005
p=0.056
0
2
4
6
8
10
12
1998 1999 2000 2001 2002 2003 2004 2005
Year of Diagnosis
p=0.003
Proportion of cases with resistance to NNRTI 1998-2005
Pro
port
ion
with
Dru
g R
esis
tanc
e (%
)
Variable Sample size% Drug
Resistant p value
Sex 0.329
Male 1701 8.8
Female 619 10.2
Risk Exposure 0.951
MSM 662 9.4
MSM/IDU 71 8.5
IDU 637 8.6
Heterosexual 685 9.2
Age 0.822
15-19 36 13.9
20-29 491 9.4
30-39 852 9.9
40-49 639 8.0
50-59 207 8.7
60+ 83 8.4
Factors associated with primary DR
VariableSample
size% Drug
Resistantp value
Time of Infection 0.130
Recent 538 10.4
Established 1421 8.2
Ethnicity 0.052
Aboriginal 550 11.1
Asian 79 8.9
Caucasian 1200 8.3
African/Caribbean 222 4.5
Subtype 0.012
B 2040 9.7
non-B 288 5.2
Factors associated with primary DR, con’t
Published August, 2006 (contains data to March 2005)
Data from SDR program generate research questions and used for other specific analyses
August 2006
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.
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
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