Abstract Book Vol. 1 [International Conference on AIDS (16th: 2006: Toronto, Canada)]

TUACO202
Male circumcision and HIV infection risk among tea
plantation residents in Kericho, Kenya:
incidence results after 1.5 years of follow-up
W.B. Sateren', C.T. Bautista', D.N. Shaffer2, G. Foglia3, M. Wassuna4,
S. Kiplangat2, F. Sawe2, D.E. Singer', M. Robb', N. Michael', D.L. Birxs.
'U.S. Military HIV Research Program at the Walter Reed Army Institute of
Research and the Henry M. Jackson Foundation, Inc., Rockville, United States,
2U.S. Army Medical Research Unit - Kenya, Nairobi, Kenya, 3U.S. Army Medical
Research Unit - Kenya (formerly), Nairobi, Kenya, 4Kenya Medical Research
Institute - KEMRI, Nairobi, Kenya, sU.S. Military HIV Research Program at the
Walter Reed Army Institute of Research and the Henry M. Jackson Foundation,
Inc., (formerly), Rockville, United States
Background: To determine the association between male circumcision and
risk of HIV infection at baseline and after 1.5 years of follow-up in an HIV
prospective cohort study.
Methods: As part of an ongoing 3-year study of HIV incidence, a total of
1,719 men were enrolled at a tea plantation in Kericho, Kenya, between June
and December 2003. Following written informed consent volunteers were
administered a sociodemographic and behavioral questionnaire and screened
for HIV infection. Circumcision status was self-determined. HIV testing was
done by ELISA and confirmed by Western blot assay. Participants returned for
follow-up HIV screening and additional questionnaires at 6, 12 and 18 months.
Incidence rates (IR) were expressed as the number of seroconverters per 100
person-years of follow-up.
Results: At baseline a high HIV prevalence was found in this study population,
11.3% (95% CI 9.8-12.8). A strong statistically significant difference in HIV
prevalence (p<0.01) was observed between the 398 uncircumcised men
(24.9%, 95% CI: 20.6-29.1) and the 1,321 circumcised men (7.3%, 95%
CI 5.9-8.7). Circumcision was found to be a protective predictor of HIV
infection (odds ratio = 0.24, 95%: CI 0.17-0.32). This protective effect was
also observed for circumcised men compared to uncircumcised men across all
strata of age groups, education, marital status, history of sexually transmitted
infection(s), and syphilis infection status. After 1.5 years of follow-up, the overall
HIV incidence rate was statistically significantly lower among circumcised men
(0.84/100 person-years, 95% CI: 0.38-1.29) compared to uncircumcised men
(2.98/100 person-years, 95% CI: 1.25-4.72), yielding an HIV incidence rate
ratio of 0.28 (95% CI: 0.13-0.63, p<0.001).
Conclusions: Circumcision plays an important role in a reduced risk of HIV
infection among men.
TUACO203
The potential benefits of expanded male
circumcision programs in Africa: predicting the
population-level impact on heterosexual HIV
transmission in Soweto
K. Mesesan', D.K. Owens2, A.D. Paltiel'. 'Yale University School of Medicine,
Department of Epidemiology & Public Health, New Haven, United States, 2VA
Palo Alto Health Care System & Stanford University, Department of Medicine,
Palo Alto, United States
Background: Male circumcision was recently shown to dramatically reduce
individual-level female-to-male heterosexual transmission of HIV in South
Africa, with additional results from Kenya and Uganda pending. We considered
the impact of expanded circumcision programs on HIV prevention.
Methods: We developed a mathematical model to simulate the population-level
impact of various male circumcision programs on HIV transmission in Soweto,
South Africa. We calculated annual rates of movement between population
groups defined by gender, male circumcision status, and disease stage. Model
parameters included
(1) 823,000 sexually-active, anti-retroviral-naive men/women,
(2) 12%(male) and 20%(female) initial HIV prevalence,
(3) 35% male circumcision,
(4) 61% circumcision protective effect,
(5) male-negotiated condom use, and
(6) varying contact (0-3 partners annually) and infectivity (0.068-0.270 perpartnership) rates by disease stage.
We evaluated potential 5-year male circumcision programs by assessing HIV
prevalence and total infections prevented over a 20-year period.
Results: When the reduction in HIV transmission from circumcision is ignored,
the model forecasts 318,000 new HIV infections over the next 20 years,
and overall HIV prevalence increases from 16% to 23%. Incorporating the
transmission reduction (61%) from current circumcision rates (35%) reduces
predicted new HIV infections to 244,000 and 20-year HIV prevalence to 17%.
A 5-year prevention program targeting an additional 10% of uncircumcised
males each year would prevent 32,000 infections and decrease 20-year HIV
prevalence to 14%. A program targeting 20% of uncircumcised males each
year would prevent 53,000 infections and decrease HIV prevalence to 13%.
Outcomes are sensitive to potential changes in risk behavior: e.g. if overall

condom use decreased by 30%, the latter program would prevent only 18,000
infections.
Conclusions: For South Africa and countries with similar epidemic profiles,
even modest programs offering male circumcision would confer enormous
benefits in terms of HIV infections averted. Because increases in sexual risk
behaviors could diminish these benefits, programs should continue emphasizing
risk-reduction counseling.

TUACO204
Cost-effectiveness of male circumcision in
sub-Saharan Africa
J.G. Kahn', E. Marseille2, B. Auvert3. 'University of California, Institute for
Health Policy Studies, San Francisco, United States, 2IHPS, UCSF, Health
Strategies International, Orinda, United States, 3Hopital Ambroise-Pare,
Assitance Publique, Hopitaux de Paris, Boulogne, INSERM U 687, SaintMaurice; University Versailles Saint-Quentin, IFR, Villejuif, France
Background: A randomized controlled trial of adult male circumcision (MC)
conducted in Gauteng Province, South Africa, demonstrated a 60% protective
effect against HIV acquisition. This study assesses the cost-effectiveness of an
MC intervention to reduce the spread of HIV in sub-Saharan Africa.
Methods: Cost-effectiveness was modeled for 1000 MCs within a general
adult male population. Intervention costs included the MC and treatment of
adverse events. HIV prevalence was estimated from published estimates and
incidence among susceptible subjects calculated for a steady-state epidemic.
Effectiveness was defined as HIV infections averted, estimated by projecting
over 20 years the reduction in HIV incidence observed in the trial. Net savings
reflect the averted lifetime costs of HIV treatment. Sensitivity analyses
examined the effects of input uncertainty and program coverage. Monte Carlo
simulations indicated 80% confidence intervals (CI). Results were obtained for
the trial province in South Africa and other sub-Saharan settings. Results are
discounted to the present at 3% annually.
Results: For Gauteng, South Africa (2005 adult male prevalence of 25.6%),
at full MC coverage, each 1000 circumcisions would avert an estimated 308
(80% CI: 189 - 428) infections over 20 years; two-thirds in men and one-third
in women. The cost is $181 (80% CI $117 - 306) per HIV infection averted
(HIA), and net savings are $2.4 million (80% CI: $1.3 - $3.6 million). Costeffectiveness is sensitive to the costs of MC and of averted HIV treatment, the
protective effect of MC, and HIV prevalence. With HIV prevalence of 8.4%,
the cost per HIA is $550 (80% CI $318 -$1 200) and net savings are $753
thousand (80%-range: $0.3 - $1.3 million). Cost-effectiveness is insensitive
to coverage.
Conclusions: In settings in sub-Saharan Africa with high or moderate HIV
prevalence among the general population, adult male circumcision appears very
cost-effective and, when adjusted for averted HIV medical costs, cost-saving.
TUACO205
Male circumcision in Siaya and Bondo districts,
Kenya: a prospective cohort study to assess
behavioural disinhibition following circumcision
K. Agot', J. Kiarie2, H. Nguyen3, J. Odhiambo', T. Onyango4, N. Weiss3. 'Impact
Research & Development Organization, Kisumu, Kenya, 2University of
Nairobi, Obstetrics & Gynaecology, Nairobi, Kenya, 3University of Washington,
Epidemiology, Seattle, United States, 4Siaya District Hospital, District AIDS &
STD Coordination, Siaya, Kenya
Background: Evidence forthe efficacy of male circumcision as an HIV prevention
measure is increasing, but the possibility that men who are circumcised may
subsequently adopt more risky sexual behaviors (behavioral disinhibition) is a
serious concern. We compared sexual behaviors of recently circumcised men
with those of uncircumcised men.
Methods: We carried out a non-randomized prospective cohort study in two
districts in western Kenya to compare sexual behaviors in a group of 324
recently circumcised men with those of 324 uncircumcised men at 1, 3, 6, 9 and
12 months after surgery/enrolment in the study. The main outcome indicators
were the incidence of sexual behaviors known to place men at increased risk of
acquiring HIV, specifically married men having sexual intercourse with partners
other than their wife/wives, and unmarried men having partners other than
their "regular" girlfriends (referred to below as "risky sex"). Condom use
was also ascertained. All men in both groups received thorough sexual risk
reduction counseling. Circumcised men were advised to not have sex for at
least one month after surgery.
Results: In the first month following circumcision, 8% of men reported having
had sexual intercourse. During that time, they were 59% less likely to report
having engaged in risky sex than men who remained uncircumcised, and 69%
less likely to report risky sex without condom use. During the remainder of the
first year of follow-up this difference disappeared, but there was no excess of
reported risky sex (with or without condom use) among circumcised men.
Conclusions: During the first year post-circumcision, men did not engage
in risky sexual behaviors to a greater degree than did uncircumcised men.
These results suggest that, within the context of adequate counseling on risk
reduction, any protective effect of male circumcision on HIV acquisition is not
likely to be appreciably offset by an adverse behavioral impact.

XVI INTERNATIONAL AIDS CONFERENCE * 13-18 AUGUST 2006 * TORONTO CANADA * ABSTRACT BOOK VOLUME 1