Vaginal microbicides save money: a model of cost-effectiveness in South Africa and the USA.
OBJECTIVE
To determine the hypothetical cost-effectiveness of vaginal microbicides preventing male to female HIV transmission.


METHODS
A mathematical epidemiological and cost-effectiveness model using data from South Africa and the USA was used. The prospective 1-year-long intervention targeted a general population of women in a city of 1,000,000 inhabitants in two very different epidemiological settings, South Africa with a male HIV prevalence of 18.80% and the USA with a male HIV prevalence of 0.72%. The base case scenario assumes a microbicide effective at 55%, used in 30% of sexual episodes at a retail price for the public sector in South Africa of US$0.51 per use and in the USA of US$2.23 per use.


RESULTS
In South Africa, over 1 year, the intervention would prevent 1908 infections, save US$6712 per infection averted as compared with antiretroviral treatment. In the USA, it would be more costly: over 1 year, the intervention would prevent 21 infections, amounting to a net cost per infection averted of US$405,077. However, in the setting of Washington DC, with a higher HIV prevalence, the same intervention would prevent 93 infections and save US$91,176 per infection averted. Sensitivity analyses were conducted and even a microbicide with a low effectiveness of 30% would still save healthcare costs in South Africa.


CONCLUSIONS
A microbicide intervention is likely to be very cost-effective in a country undergoing a high-level generalised epidemic such as South Africa, but is unlikely to be cost-effective in a developed country presenting epidemiological features similar to the USA unless the male HIV prevalence exceeds 2.4%.
Department of Mechanical Engineering, University of California, Berkeley, California, USA. verguet@uw.edu
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Verguet
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Walsh
D000282:Administration, Intravaginal; D000293:Adolescent; D000328:Adult; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage* / Q000191:economics; D017280:Condoms / Q000191:economics / Q000706:statistics & numerical data; D017046:Cost Savings; D003362:Cost-Benefit Analysis; D016527:Drug Costs; D005260:Female; D015658:HIV Infections / Q000191:economics / Q000453:epidemiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013019:South Africa / Q000453:epidemiology; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D000891:Anti-Infective Agents, Local