Charlotte Watts, PhD¹, Lilani Kumaranayake¹, Peter Vickerman¹, Fern Terris-Prestholt¹, and Lori Heise². (1) Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom, (2) Program for Appropriate Technology in Health (PATH), Global Campaign for Microbicides, 1800 K St. N.W., Suite 800, Washington, DC 20006, 202 822 0033, lheise@path-dc.org

Purpose: First generation vaginal microbicides may be 50-60% efficacious. We estimated their impact using mathematical and economic modeling techniques.

Data Used: Using demographic, behavioral, epidemiological and economic data, we estimated the impact of a 60% efficacious microbicide if used by 20% of the sexually active people accessing existing services in 73 lower income countries.

Methods: In each country we consider four groups: sex workers contacted through HIV prevention interventions; adolescents in school; injecting drug users using harm reduction services; and women in steady partnerships using contraception. We assumed microbicide use in 50% of sex acts not protected by a condom. Using country specific demographics, HIV prevalence data and four deterministic epidemiological models, we estimated the impact on HIV and STI transmission patterns and HIV infections averted. We also estimated health care costs avoided and productivity savings (through preventing absenteeism and worker retraining/replacement) with a simple disease progression model and published cost data.

Results: 2002 calculations estimate that 2.5 million HIV infections could be averted in men, women and children over three years in both endemic (sub-Saharan Africa) and emergent (South and East Asia) regions. Through the combined effect of product efficacy and coverage, even a low efficacy microbicide may have substantial impact if used by a large number of people. Using more recent data, we are updating the above calculations and associated economic benefits. These will be presentation at the meeting.

Policy Implications: Microbicides could play an important role in HIV prevention. Their development and distribution are a high priority.

Learning Objectives: At the conclusion of the session, the participant (learner) in this session will be able to

• Recognize why even a partially effective microbicide may have substantial impact on HIV transmission rates
• Briefly describe the scientific process through which this estimation of impact was developed.
• Apply the concept of impact being the result of technical efficacy, consistency of use and coverage (levels of actual uptake by the population) to other prevention interventions.

Keywords: HIV Interventions, International Public Health

Related Web page: www.global-campaign.org

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.