Male Circumcision for Prevention of HIV Transmission: What the New Data Mean for HIV Prevention in the United States
et al. (2007) Male circumcision for
prevention of HIV transmission: What the new data
mean for HIV prevention in the United States. PLoS
Med 4(7): e223. doi:10.1371/journal.pmed.0040223
Male Circumcision for Prevention of HIV Transmission: What the New Data Mean for HIV Prevention in the United States
Patrick S. Sullivan 0
Peter H. Kilmarx 0
Thomas A. Peterman 0
Allan W. Taylor 0
Allyn K. Nakashima 0
Mary L. Kamb 0
Lee Warner 0
Timothy D. Mastro 0
0 Patrick S. Sullivan, Peter H. Kilmarx, Allan W. Taylor, Allyn K. Nakashima, and Timothy D. Mastro are with the Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America. Thomas A. Peterman and Mary L. Kamb are with the Division of Sexually Transmitted Disease Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America. Lee Warner is with the Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America. The findings and conclusions in this commentary are those of the authors, and do not necessarily represent the views of the Centers for Disease Control and Prevention
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Tclinical trials in South Africa,
hree randomized, controlled
Kenya, and Uganda were
recently unblinded early because
interim analyses concluded that
circumcision of HIV-negative adult
males reduced their risk for acquiring
HIV infection through penilevaginal
sex [13]. In each trial, men who
had been randomly assigned to
an intervention group receiving
circumcision had a lower incidence
of HIV infection in up to two years
of follow up, compared to men who
were assigned to a control group not
receiving circumcision. The estimated
reduction in the risk of HIV infection
ranged from 51% to 60%; per-protocol
estimates of risk reduction ranged from
55% to 76%.
It is now clear that male circumcision
can be efficacious for men in reducing
their risk of HIV acquisition through sex
with women [4]. Some experts predict
that the impact of male circumcision
as a biomedical intervention for HIV
prevention in Africa could be large
[5,6], and preparatory work has been
done to establish male circumcision
programs in Africa. The implications
of African trials on circumcision for
HIV prevention programs in the
United States are less cleardespite
the interest of the popular press in
the idea [7]. Here, we consider the
differences between the HIV epidemics
in Africa and the US, the current status
of male circumcision in the US, and
the knowledge gaps that will need to
be addressed as we consider whether
male circumcision should be evaluated
or implemented as a biomedical
intervention to reduce sexually acquired
HIV infections domestically.
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Epidemiological Differences
The results of any trial must be
interpreted with the caution that
inference not be extended to
populations differing from the study
participants in important ways.
The HIV epidemics in Africa are
substantially different from the US
epidemic. Generalized HIV epidemics
exist in many areas of Africa, and
the population prevalence of HIV
among adult Kenyans, Ugandans,
and South Africans ranges from
6%19% [8]. The predominant
mode of HIV transmission in Africa is
malefemale sex. In contrast, the US
has a concentrated epidemic, with most
sexual transmission occurring among
men who have sex with men (MSM).
The general population prevalence of
HIV is about 0.4% in the US [9], and
only 15% of men diagnosed with HIV
infection during 2005 were reported
to have acquired HIV through male
female sex [10].
Biological Plausibility of
Circumcision to Prevent HIV
Acquisition
The association between circumcision
and reduced risk for HIV acquisition
is biologically plausible: the foreskin
contains high concentrations of
superficial Langerhans cells, CD4+ T
cells, and macrophages [11]all target
cells for HIV infection, some of which
may also be close to the skin surface
[12,13]. In addition, the preputial
sac may serve as a reservoir for
HIVcontaining secretions, resulting in
prolonged contact time after exposure
to secretions, and the foreskin may
present less of a physical barrier to HIV
entry than the more heavily keratinized
skin of the shaft of the penis [12], and
may have more frequent epithelial
disruption. There are also potential
indirect mechanisms of association
between lack of circumcision and HIV
risk; for example, lack of circumcision
is associated with increased risk of
genital ulcer diseases, which in turn are
associated with increased risk of HIV
transmission and acquisition [14].
Considerations for Prevention
of HIV Transmission by Penile
Vaginal Sex in the US
Epidemic differences are important
because, on a population basis,
the impact of circumcision as an
intervention to prevent HIV infection
among men who have sex with women
will depend on th (...truncated)