Transcript Trends in High-Risk Sexual Behaviour Among Homosexual Men

Acknowledgements
• For help in recruitment:
• Action Séro
-
M
O
H
L
T
C
,
L
a
b
o
r
a
t
o
r
i e
s
B
r
a
n
c
h
•
A
•
H
,
I
M
C
–
2
0
I
D
e
0
1
S
a
C
l
t
h
o
H
m
o
m
u
i
n
d
t
t
e
s
e
,
o
G
f
l
e
T
n
o
r
B
Z
o
r
é
n
o
t
w
r
o
,
C
o
h
o
r
t
e
O
m
é
g
a
o
n
&
A
s
s
o
c
i
a
t
e
s
C
o
n
s
u
l
t
i
Background
• Behavioural modification can only reduce HIV
transmission; HIV continues to spread, especially in
developing world
• HIV vaccine is desperately needed
• AIDSVAX is only vaccine in Phase III trial
• Began in summer 1998 in U.S.
• Canadian sites include Montreal, Toronto and
Vancouver; recruitment July to October 1999
• Sexual behaviour is of concern
• Report on data on sexual behaviour to 12 months
MOHLTC, Laboratories Branch, IMC – 2001
Study objectives
• To examine trends in risky sexual behaviour among
participants in the Canadian sites of the AIDSVAX
Phase III trial
• To compare sexual behaviour among participants
from Canada, US and Netherlands
MOHLTC, Laboratories Branch, IMC – 2001
HIV vaccine trial
• Double-blind, placebo-controlled trial of bivalent
rgp120 HIV-1 vaccine (AIDSVAX® B/B)
• Subjects are men aged 18–60 years who report anal
sex with a male partner in the previous year
• HIV-negative at first screening
• Receive 7 doses of vaccine or placebo (2:1) over 2½
years (0,1,6,12,18,24 and 30 months).
MOHLTC, Laboratories Branch, IMC – 2001
Data source and analysis
• Risk reduction counseling provided at each visit
• Questionnaire on sexual behaviours in the previous
6 months
• Compare proportions at baseline and over time in 3
countries
• Data extracted at VaxGen Inc
• Significance testing by chi-square
MOHLTC, Laboratories Branch, IMC – 2001
Demographic characteristics
at baseline
Canada
n=291
US
n=5,007
Netherlands
n=120
37.6
37
18 – 59
36.4
36
18 – 62
37.1
36
18 – 58
93%
2%
1%
1%
3%
82%
7%
7%
1%
2%
96%
0%
3%
1%
0%
29%
40%
31%
40%
40%
20%
41%
42%
18%
Age (years)
Mean
Median
Range
Race
White
Hispanic
Black
Asian
Other
Education
<=High school
College
Graduate degree
MOHLTC, Laboratories Branch, IMC – 2001
History of drug use and sexually
transmitted diseases at baseline
Canada
n=291
Any injection of drugs
Smoked crack
Snorted cocaine/heroine
Amphetamine
STD
Syphilis
NGU
MOHLTC, Laboratories Branch, IMC – 2001
US
n=5,007
Netherlands
n=120
p-value
0.0%
2.4%
14.4%
12.7%
0.2%
2.0%
12.3%
8.9%
0.0%
5.8%
10.8%
5.8%
NS
0.01
NS
0.04
1.7%
0.3%
3.4%
2.2%
0.1%
3.2%
2.5%
0.0%
5.8%
NS
NS
NS
Sexual behaviours (previous
6 months) at baseline
Canada
n=291
US
n=5,007
Netherlands
n=120
p-value
16.6
39%
52%
53%
32%
43%
12.6
32%
43%
58%
37%
47%
20.4
58%
32%
48%
28%
37%
0.001
0.02
0.05
0.03
90%
41%
40%
21%
33%
82%
27%
39%
21%
32%
98%
23%
32%
16%
22%
0.001
0.001
NS
NS
0.05
Male partners
Mean number
10+ partners
Oral sex
Any unprotected anal sex
Unprotected receptive anal
Unprotected insertive anal
Male HIV+/? partners
Had an HIV+/? partner
Oral sex
Any unprotected anal sex
Unprotected receptive anal
Unprotected insertive anal
MOHLTC, Laboratories Branch, IMC – 2001
Trends in unprotected anal sex
reported (previous 6 months), Canada
45%
UIAS
URAS
UAS
Proportion reporting
40%
35%
30%
25%
20%
15%
10%
5%
0%
0
6
Visit (months)
MOHLTC, Laboratories Branch, IMC – 2001
12
Trends in receptive anal sex with HIV+/? partner,
Canada, US and Netherlands
45%
Canada
US
Netherlands
Proportion reporting
40%
35%
30%
25%
20%
15%
10%
5%
0%
0
6
Visit (months)
MOHLTC, Laboratories Branch, IMC – 2001
12
Trends in unprotected receptive anal sex with
HIV+/? partner, Canada, US and Netherlands
Proportion reporting
25%
Canada
US
Netherlands
20%
15%
10%
5%
0%
0
6
Visit (months)
MOHLTC, Laboratories Branch, IMC – 2001
12
Limitations
• Subjects not representative of gay population
• Data on sexual behaviour self-reported
• Decreases in sexual behaviour could be due to
selective drop-out and infection;
however, unlikely given the low attrition rate
MOHLTC, Laboratories Branch, IMC – 2001
Conclusions
• Subjects are engaging in high risk sexual behaviour
• This will provide sufficient power to measure
HIV vaccine efficacy
• Participation does not appear to lead to increasing
risky sexual behaviour
• Study subjects and trends in sexual behaviour
generally comparable in 3 countries
MOHLTC, Laboratories Branch, IMC – 2001