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CSU 20/2009: 1) READER COMMENT / 2) MODELING THE IMPACT OF MALE CIRCUMCISION/ CALMETTE AND GUERIN

Friday, 10th of April 2009 Print

CSU 20/2009: 1) READER COMMENT / 2) MODELING THE IMPACT OF MALE  CIRCUMCISION/  CALMETTE AND GUERIN
  
 
 1) READER COMMENT
  
 
 Reader Bob Bailey, of the University of Illinois, comments as follows on
 the social science side of male circumcision:
  
 
 ‘The below is the reference to a review of acceptability studies in
 nine different  countries in sSA. Also, for answers to many questions about circumcision,
 you might want to turn to the website recently created by WHO/UNAIDS
 entitled, The Male Circumcision Clearinghouse. The website is
 
 at  http://www.malecircumcision.org/publicationsmale_circumcision_publications.html
 
  
 Westercamp N, Bailey RC. Acceptability of male circumcision for prevention
  of HIV/AIDS in sub-Saharan Africa: a review. AIDS Behav 2007;11(3):341-355.
 
 
  2) MODELING THE IMPACT OF MALE CIRCUMCISION
 
 
 Writing in the International Journal of Epidemiology, Gray and colleagues
 review the evidence on male circumcision and HIV prevention, especially in
 the light of different models of roll-out options for MC. Their conclusions,
 quoted in the excerpts below, and those of Londish and Murray, are likely
 to generate much discussion.
  
 Where 5 to 15 circumcisions prevent a single HIV infection, then MC is
 extremely cost-effective. Few interventions prevent HIV for a unit cost of <
 $1000 per new infection, a figure likely to be achieved in high prevalence
 countries where circumcision costs less than $50 per procedure. More
 contentious is a low priority to infant circumcision, which takes little
 account of the fact that circumcision of neonates is relatively simpler and
 less expensive, and that HIV/AIDS in Africa is likely to remain a pandemic
 in future decades, when today’s infants become sexually active. Among older
 age groups, some writers on the subject would prioritize boys in their teens
 rather than the 20-34 year age group.
  
 There is no 'either-or' here; the same resources can serve to
 circumcise younger boys, adolescent males and adults.
  
 From the editorial:
  
 ‘In most sub-Saharan African settings, the number of surgeries per HIV
 infection averted over a decade ranges from 5–15, depending on male HIV
 incidence. This makes circumcision a highly cost effective intervention,
 particularly when costs are discounted by savings for future antiretroviral
 care due to prevention of HIV acquisition.’
  
 ‘. . . as suggested by Londish and Murray, priority might be given to men
 aged 20–34 among whom incidence is generally greatest in Africa, and
 because such  men often have relationships with younger female partners, the derivative
 benefits to women are likely to be maximized. . .’
  
 ‘ Models can also address the question of whether to devote resources to
 surgery in adolescents and adults, or to infant circumcision. Again, the
 results are clear. Adolescent and adult surgery will reduce HIV over 10–20
 years, whereas with infant circumcision, HIV impact will be delayed for more
 than 20 years due to delayed onset of sexual activity.’
  
 Both the editorial, and the article by Londish and Murray from the same
 journal, are available online, with weblinks. The article is at
 http://ije.oxfordjournals.org/cgi/content/abstract/37/6/1246 and the
 editorial is at http://ije.oxfordjournals.org/cgi/content/full/37/6/1253 .
  
 Good reading.
  
 BD
 
 
 
 International Journal of Epidemiology, Volume 37, Number 6, Pp. 1253-1254
 
 Published by Oxford University Press on behalf of the International
 Epidemiological Association © The Author 2008; all rights reserved.
 
 
 
 Commentary: Disease modelling to inform policy on male circumcision for HIV
 prevention
 
 
 
 Ronald H Gray1,, Maria J Wawer 1, Godfrey Kigozi 2 and David Serwadda 3
 
 
 
 1 Johns Hopkins University, Bloomberg School of Public Health, Baltimore,
 Maryland, USA.
 
 2 Rakai Health Sciences Program, Entebbe, Uganda.
 
 3 School of Public Health, Makerere University, Kampala, Uganda.
 
  Corresponding author. E-mail: rgray@jhsph.edu
 
 
 
 Accepted 7 April 2008
 
 
 
 The findings from three randomized trials 1–3 and multiple observational
 studies4 that male circumcision prevents HIV acquisition in men has been
 welcomed as an historic opportunity to control the HIV epidemic,
 particularly in sub-Saharan Africa.5 However, the challenges are daunting
 because we have never attempted to use surgery as a means of controlling an
 infectious disease, the African health infrastructure is weak and trained
 personnel required to provide circumcision surgery on a massive scale are
 limited. Therefore, modelling the impact of circumcision on the future
 course of the HIV epidemic is needed to persuade health authorities and
 donors to invest resources in this unprecedented initiative.
 
 
 
 The paper by Londish and Murray in this volume 6 adds to the growing body of
 models, all of which suggest that circumcision has the potential to abate
 but not abolish the African HIV epidemic over a period of 10-20 years.7–10 A
 variety of model projections were reviewed at a recent Joint United Nations
 Programme on AIDS (UNAIDS) meeting at Imperial College, London (March 5–6,
 2008). A report will be forthcoming. The models have varied in their
 assumptions and structures, and in the endpoints used (e.g. HIV prevalence
 or incidence over time, HIV infections or AIDS deaths prevented, the number
 of surgeries needed to avert one HIV infection and the costs per infection
 averted). Irrespective of these differences in modelling methods and
 outputs, the direct biological effect of circumcision on reducing HIV
 acquisition in men by 60%, and the secondary protection afforded to women
 via reduced exposures to HIV infected men, are so overwhelming that, under
 most plausible scenarios, the impact of circumcision on the African HIV
 epidemic is clear and substantial. The impact of circumcision will likely be
 greatest in settings, such as those in southern Africa, where HIV incidence
 is high and the prevalence of circumcision is low.
 
 
 
 The circumcision trials provide an estimate on the numbers needed to treat
 per HIV infection over a short period of two years. However, since the
 efficacy of circumcision is likely to be life long, models can estimate the
 number of surgeries needed to prevent one HIV infection over a period of
 10–20 years. In most sub-Saharan African settings, the number of surgeries
 per HIV infection averted over a decade ranges from 5–15, depending on male
 HIV incidence. This makes circumcision a highly cost effective intervention,
 particularly when costs are discounted by savings for future antiretroviral
 care due to prevention of HIV acquisition.
 
 
 
 Other policy relevant questions addressed by modelling include whether to
 provide services to all men or to focus on specific segments of the
 population such as limited age groups or subgroups with higher sexual risk
 behaviours. Thus, as suggested by Londish and Murray, priority might be
 given to men aged 20–34 among whom incidence is generally greatest in
 Africa, and because such men often have relationships with younger female
 partners, the derivative benefits to women are likely to be maximized.
 Similarly, a focus on high risk core groups such as STD clinic attendees or
 clients of commercial sex workers might provide greater benefit. However,
 there are practical limitations to such strategies. First, HIV prevalence
 will be high in such high incidence subgroups, and since circumcision of
 HIV-infected men does not appear to directly benefit women,11 the impact of
 the program will be diluted and there would be substantial number of
 surgeries in already HIV infected men who may infect their female partners
 if intercourse is resumed before full wound healing is complete.11 Second,
 such ‘targeting’ could exclude large segments of the male population who,
 given the belief that circumcision is protective, might seek services from
 unsafe sources. Therefore, although models predict greater impact from
 targeting specific adult age or risk groups, this may be of limited
 practical programmatic value.
 
 
 
 Models can also address the question of whether to devote resources to
 surgery in adolescents and adults, or to infant circumcision. Again, the
 results are clear. Adolescent and adult surgery will reduce HIV over 10–20
 years, whereas with infant circumcision, HIV impact will be delayed for more
 than 20 years due to delayed onset of sexual activity. Similarly, models can
 provide guidance for the speed of program scale up. Rapid achievement of
 high circumcision coverage will maximize impact by more rapidly preventing
 new HIV infections in the population.
 
 In summary, modelling the effectiveness of circumcision for HIV prevention
 can be an important tool for policy and planning. The only remaining
 question is whether policy makers will use this information in their
 decision making, whether they will devote resources to this initiative, and
 whether programs can be brought to scale in a timely manner.
 
 
 
 References
 
 
 
 1 Gray RH, Kigozi G, Serwadda D, et al. Male circumcision for HIV prevention
 in men in Rakai, Uganda: a randomized trial. Lancet (2007) 24:657–66.
 
 2 Bailey RC, Moses S, Parker CB, et al. Male circumcision for HIV prevention
 in young men in Kisumu, Kenya: a randomized controlled trial. Lancet (2007)
 369:643–56.[CrossRef][ISI][Medline]
 
 3 Auvert B, Taljaard D, Lagarde E, Sobngwi-Tambekou J, Sitta R, Puren A.
 Randomized, controlled intervention trial of male circumcision for reduction
 of HIV infection risk: the ANRS 1265 Trial. PLoS Med (2005) 11:e298. Epub
 2005 October 25. Erratum in: PLoS Med 2006 May;3:e298.
 
 4 Weiss HA, Quigley MA, Hayes RJ. Male circumcision and risk of HIV
 infection in sub-Saharan Africa: a systematic review and meta-analysis. AIDS
 (2000) 14:2361–70.[CrossRef][ISI][Medline]
 
 5 WHO and UNAIDS press release on recommendations for male circumcision on
 prevention of HIV infection (March 28 2007). Available at:
 http://www.who.int/mediacentre/news/releases/2007/pr10/en/print.html.
 
 6 Londish GC, Murray JM. Significant reduction in HIV prevalence according
 to male circumcision intervention in sub-Saharan Africa. Int J Epidemiol.
 (2008) 37:1246–1253.[Abstract/Free Full Text]
 
 7 Nagelkerke NJ, Moses S, de Vlas SJ, Bailey RC. Modelling the public health
 impact of male circumcision for HIV prevention in high prevalence areas in
 Africa. BMC Infect Dis (2007) 7:16.[CrossRef][Medline]
 
 8 Gray RH, Li X, Kigozi G, et al. The impact of male circumcision on HIV
 incidence and cost per infection prevented: a stochastic simulation model
 from Rakai, Uganda. AIDS (2007) 21:845–50.[ISI][Medline]
 
 9 Kahn JG, Marseille E, Auvert B. Cost-effectiveness of male circumcision
 for HIV prevention in a South African setting. PLoS Med (2006)
 3:e517.[CrossRef][Medline]
 
 10 Williams BG, Lloyd-Smith JO, Gouws E, et al. The potential impact of male
 circumcision on HIV in Sub-Saharan Africa. PLoS Med (2006)
 3:e262.[CrossRef][Medline]
 11 Wawer M, Kigozi G, Serwadda D, et al. Trial of male circumcision in HIV+
 men, Rakai, Uganda: Effects in HIV+ men and in women partners. Proceedings
 of the 15th Conference on Retroviruses and Opportunistic Infections. Boston,
 February 3–6, 2008. Abstract 33LB CROI, Alexandria, VA.
 
 3) CALMETTE AND GUERIN
 
 Most readers of these updates are familiar with BCG, but some may not know
 about the two French researchers who gave their names to the Bacille
 Calmette-Guerin, a modified form of Mycobacterium bovis used in most
 countries against tuberculosis (some studies show a protective effect of BCG
 against leprosy as well).
 
 See their story at http://www.technet21.org/Articles/BCG_vaccine.html
 Cross-posted, with thanks, from EPI Technet.

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