Superinfection (Reinfection): New Study in San Francisco Offers Free Resistance and Viral Load Testing.

A new study in San Francisco will try to find out if someone who already has HIV can be additionally infected with a different strain of HIV. Some experts doubt that such "superinfection" can occur-but no one knows because cases would not be found by the tests used in standard medical care.

The answer is very important, for at least three reasons:

(1) If two people who both have HIV have unprotected sex with each other, are they at risk of additional infection with a new strain (which might be more virulent, or might already have resistance to certain antiretrovirals, or could worsen the illness or complicate treatment in other ways)?

(2) Whether or not superinfection occurs is very important for vaccine research. If infection with one strain cannot prevent infection with another, it would probably be difficult (although not impossible) for a vaccine to do so.

(3) If superinfection does not occur it would be good news for HIV-positive patients who need organ transplantation for any reason, since it would suggest that organs from HIV-positive donors could be used (instead of being thrown away, as happens now).

This study, called Positive Partners, will initially enroll 20 sexually active HIV-positive couples. Here is a description from the researchers, including an explanation of who can participate, and contacts for more information. Note that this study requires only two visits to the research site in San Francisco, for interviews and blood draws. It does not provide drugs nor require any changes in one's treatment.

Can drug-resistant HIV be transmitted to someone already HIV-positive? The Positive Partners Study will try to find out!

Who is conducting this study and why?

The Positive Partners Study (P2) is a collaboration between Dr. Robert Grant of the Gladstone Institute of Virology and Immunology and Dr. Greg Greenwood at the Center for AIDS Prevention Studies to study super infection. P2 is a new and unique study to demonstrate that it is feasible to recruit, interview, and follow seroconcordant HIV-positive partners. P2 is designed to examine whether new drug resistant strains of HTV - 1 can be sexually transmitted between partners who are already both HIV-positive (superinfection). This project is one key element in Dr. Grant's broader virological research involving reexamination of data from several other UCSF studies for evidence of superinfection.

Who can participate?

Positive Partners will initially enroll 20 sexually active, HIV-positive partners (M/M, M/F, & M/TG) who are both taking HIV medications. Participants must be 18 years old or older. Recruitment is on going so please share this information with people who might be interested.

What will participants have to do?

Positive Partners will conduct two one-on-one confidential interviews with each participant. We pay $25 in cash for each interview completed. In addition, we offer FREE drug resistance genotyping and phenotyping tests. These tests determine the genetic structure of the present HIV strain and how the strain stands up to medications being taken by persons living with HIV. The tests are fairly new to the market and are not covered by many insurance plans. They can cost a patient upwards of $2000. We provide this testing free of charge and will make the results available to each participant and their physician, if the participant chooses to release this information. We will also test for the participant's T-cell count and viral load. In case where participants experience a one-log increase in viral load during the study year we ask them to come in for an additional interview and specimen collection to see if the increase is a result of a superinfection. In a case like this where there has been a large increase in viral load the drug resistance tests we provide can help participants and their providers make medical decisions.

Laboratory assays will identify similarities and differences in partners' viruses that will indicate if superinfection has occurred (at baseline and 1-year follow-up).

If I am interested and would like to screen or get more information, where do I call?

If you or a patient, friend, or partner is interested in participating or hearing about the study, Positive Partners can be reached at 415-597-9292.

Where is Positive Partners located?

Positive Partners is located at 74 New Montgomery, Suite 600. This is downtown San Francisco between Market and Mission Street, just off the BART/MUNI Montgomery Street station.