Dr. Pilcher, et al. presented the updated experience with the North Carolina screening and tracing active transmission program (STAT) which was first published in JAMA (2002; 288; 216-221). A key feature of the approach is to screen HIV antibody negative samples with a pooled RNA approach that efficiently allows for the identification of HIV RNA positive samples at a cost of about $2 per test. This approach allows for the identification of persons who are in the process of seroconverting. From the epidemiologic perspective, it is important to recognize incident HIV, and from the prevention standpoint, the approach allows for access to sexual networks and the potential to interrupt transmission at a time when the risk is highest.

Over 12 months, 117,000 samples were tested for HIV antibodies. Seven hundred fifty-five were HIV Ab positive, with 130 identified to be recent infection (more likely white men who have sex with men [MSM]). Twenty-three samples (4%) were Ab negative RNA positive (picked up by the STAT program), of which 22/23 patients started antiretroviral therapy (ART), with 12 of these patients entering clinical trials. Forty-one at-risk partners received HIV testing and five were found to be HIV positive (four acutely).

The overall cost was $1,500 per case diagnosed. Thirteen of the 23 people who tested positive had experienced acute retroviral syndrome (seven of the people already had symptoms when they tested and six later developed symptoms). Eight of the people who tested positive had additional symptoms due to sexually transmitted disease (STD). The median HIV level at initial screening was 209,000 copies/mL. Overall, an additional 4% of the HIV antibody negative samples were actually HIV positive, with a rate of 6% for samples originating from STD clinics. This approach provides information about where to target resources by geographic technology monitoring. The new cases were noted to have a limited distribution in rural areas, mostly along trucking/interstate routes. This allowed the identification of contact networks.

Risk associations included: MSM (11), anonymous partner (4), sex work (5), crack cocaine (8), prison release (5), with a small number of college students (black MSM). Eleven of the subjects were likely transmitters (three perhaps to two or more other persons), with 10 involved with previously diagnosed HIV-positive persons and nine in long-term relationships.

A key take-home lesson was that, in some high-risk populations, HIV antibody testing may be inadequate to confidently rule out HIV infection (in STD clinic settings and prisons the additional testing picked up 6% more HIV+ cases). Although resource intensive, the costs pale in comparison to the costs of HIV care/year, so an expanded use of this innovative approach may be warranted. However, this seems unlikely to occur considering the overall poor state of public health funding in the U.S.

Reference

Abstract: The "Screening and Tracing Active Transmission" Program: Real-Time Detection and Monitoring of HIV Incidence (Oral 20)
Authored by: C. Pilcher, E. Foust, J. McPherson, R. Ashby, J. Owen-O'Dowd, T. Nguyen, R. Lee, S. Fiscus, P. Leone
Affiliations: Univ. of North Carolina at Chapel Hill, NC; North Carolina Dept. of Hlth. and Human Svcs., Raleigh, NC