Development of Assays to Estimate HIV Incidence: Meeting Proceedings

Fifty leading HIV-prevention experts gathered on May 13-14, 2009 to advance the development and validation of HIV incidence assays -- tests that are used to identify the number of recent HIV infections in a population within a given time period. Virologists, immunologists, assay developers, industry representatives, public health scientists, and epidemiologists from around the world participated in interactive, problem-solving sessions to propose how best to improve the use of current HIV incidence assays and to develop new assays, as well as to determine the global demand for these assays. The meeting was convened by Family Health International (FHI), with funding from the Bill & Melinda Gates Foundation, and support from the World Health Organization (WHO), the HIV Prevention Trials Network (HPTN), and the Center for HIV/AIDS Vaccine Immunology (CHAVI). Dr. Timothy Mastro, Vice President for Health and Development Sciences at FHI, chaired the meeting.

Background

Development of accurate methods to determine HIV incidence is crucial for the fight against HIV. Without accurate measures for HIV incidence, scientists cannot determine whether the number of new HIV infections is increasing or decreasing, or whether new HIV prevention and treatment strategies are working to slow the epidemic. Traditional methods of HIV incidence determination, such as cohort studies, are slow, expensive, logistically challenging, subject to bias, and difficult to sustain. 

Scientists have been developing a variety of HIV incidence assays based on the principle that a person's immune response to HIV evolves over the course of infection. In theory, a person with a recently acquired infection could be identified by an immature antibody response in his or her blood. In practice, however, current tests frequently misclassify a long-standing infection as a recent infection, resulting in inaccurate HIV-incidence estimates.

The need for improved HIV incidence assays is only part of the problem. Scientists also need better statistical methods to design and interpret HIV incidence surveys in populations. Furthermore, a recent FHI survey of scientists, program leaders, donors, clinicians, and other stakeholders uncovered several fundamental issues that also must be resolved. For example, stakeholders hold diverse opinions on the reliability of the current assays and many are confused about the terminology. Many also believe that the market's demand for HIV incidence assays is too low to drive the development of new assays in the commercial sector.

Results of the Meeting

The Chapel Hill meeting marked the first time that a large group of leading experts, including industry representatives, has gathered to discuss the status and the future of HIV incidence testing. The high level of interest in the gathering reflects the vital need to obtain accurate estimates of the HIV incidence in populations.

Among the most notable outcomes of the meeting were the identification of initial steps needed to develop improved HIV incidence assays, and ways to make better use of existing assays. Additionally, the participants discussed the potential use of new biomarkers for HIV incidence assays, identified the infrastructure needed to develop and evaluate HIV incidence assays, and outlined the optimal specifications and requirements for new assays.

The meeting also provided information that will allow FHI researchers to assess the market and estimate the demand for HIV incidence assays. The WHO Technical Working Group on HIV Incidence Assays will coordinate the development of guidance documents on standardized terminology and optimal use of HIV incidence assays for various public health, research, and epidemiologic applications.

For more information, please see the meeting proceedings (PDF, 917 KB).