LINTHICUM, MD, October 20 - A new simulation model that gauges the potential success of HIV prevention programs will be presented by a team of Canadian researchers at the national convention of the Institute for Operations Research and the Management Sciences (INFORMS) in Seattle. The convention is taking place at Washington State Convention & Trade Center and The Sheraton Seattle Hotel & Towers from Sunday, October 25 to Wednesday, October 28. The researchers present their findings on Sunday, October 28 from 4:30 - 6 PM.
Linking Prevention and the Epidemic
Given the complexity of HIV, the UBC simulation model hypothetically recreates the epidemic and, more significantly, possible interventions, including how each would impact the course of the infection. Among the prevention techniques evaluated are media campaigns, group counseling, condom distribution, and needle exchange programs.
In a departure, the model measures not only a program's success at educating those at risk but also actual changes in behavior - a more direct indicator of likeliness to contract or avoid contracting HIV. The researchers argue that measuring the number of people who have developed HIV, and not just the number of people reached through prevention programs, is a marked improvement in determining a program's potential success.
The model helps determine the expected cost and benefit of different types of intervention. This economic information is vital to policymakers who must make tactical choices and plan budgets to slow the spread of the AIDS virus.
The Challenge
The study addresses a conundrum facing researchers: Since it is impossible to know how many cases of HIV would have occurred in the absence of concerted prevention efforts, how does one count what doesn't happen? In proposing their model, the researchers observe that there have been few large scale efforts at evaluating prevention programs. Previous research has often considered specific populations - for example gay men in one city or intravenous drug users in another - but not how populations interact and affect one another.
Efforts at HIV education have proceeded under the assumption that education leads to a change in behavior - a conclusion that ought to be verified, say the authors. They also observe that evaluation tools covered in academic literature frequently don't credit the full value of intervention, often overlooking the multiplier effect: One less infection today translates into more than one case averted.
The Data
In developing their model, the researchers examined data on 12 groups based on gender, sexual orientation, and injection drug behavior. Each of the 12 groups was also divided into risk factors of high, medium, and low. The researchers adapted a theory about the way people change - the social theory of stages of behavior change -and focused on two stages - contemplation of change and action - to evaluate the degree to which prevention programs influence participants. Data on the financial cost of HIV prevention in Canada is based on a 1997 study by Canadian Policy Research Networks, Inc.
The paper, "Modeling the Impact of Prevention in the Spread of HIV for the Purposes of Economic Evaluation" is by Nancy L. Meagher, Robin A. Hanvelt, Tobin T. Copley, David G. Schneider, and Stephen A. Marion of the Department of Health Care and Epidemiology, University of British Columbia in Vancouver.
For additional information on the conference, including a full list of workshops, visit the web site at http://www.informs.org/Conf/Seattle98/
The Institute for Operations Research and the Management Sciences (INFORMS) is an international scientific society with 12,000 members, including Nobel Prize laureates, dedicated to applying scientific methods to help improve decision-making, management, and operations. Members of INFORMS work in business, government, and academia. They are represented in fields as diverse as airlines, health care, law enforcement, the military, the stock market, and telecommunications.