by Bob Roehr
"Don't screw with the flu" could become a new slogan for HIV prevention.
That's because up to 80 percent of persons newly infected with HIV experience flu-like symptoms. Viral load is sky high in the period immediately after that, until your immune system kicks in and suppresses the virus to an individual set point of chronic infection.
Viral load is the strongest predictor of transmission to another person and someone in acute HIV infection (AHI) is about 10 times more likely to transmit the virus as someone in a state of chronic infection, regardless of the mode of transmission. A study of serodiscordant heterosexual couples in Rakai, Uganda found that about half of all new infections through vaginal sex occurred during AHI.
The cornerstone of HIV prevention has been "getting people to test, know their antibody status, and act accordingly," says Steve Morin, director of the Center for AIDS Prevention Studies at the University of California, San Francisco.
But that simply does not apply during AHI. You do not "test positive" when you are most infectious because the standard ELISA test that is used to screen for HIV measures antibodies, not the virus itself.
New data presented at the 2007 National HIV Prevention Conference in Atlanta on Dec. 5 focused on AHI. The pilot study enrolled patients who were referred to it because of flu-like symptoms, as well as those identified through blood screening that looked for the virus rather than antibodies to it.
The purposes of the study were to determine whether it was possible to identify participants during AHI, better understand the dynamics that led to their infection, and determine the feasibility of intervening during AHI to reduce the risk of ongoing transmission.
Study participants had their blood drawn and underwent extensive initial interviews within five weeks of becoming infected and then ten weeks later. Each session could go two hours or more. The purpose was to try to reconstruct both the events and attitudes of the participants in the few weeks immediately before and after infection.
Despite participation by six of the leading HIV research centers in the country, the analysis was based on only 27 patients. That is an indication of how difficult it can be to identify persons during acute infection, particularly when people are not aware of it.
Uninformed
Robert Remien, PhD, from Columbia University HIV Center for Clinical and Behavioral Studies, said many of the participants had no knowledge of AHI. They did not understand that they were at higher risk of transmission during AHI, even though most of them were tested for HIV on a regular basis
One person infected both his boyfriend and a regular sex partner outside of that relationship during the first few weeks of AHI. He expressed remorse after learning those facts and said if he had known that the flu-like symptoms he experienced might be AHI, he might have used a condom until he got tested.
Another participant was aware that the flu-like symptoms he was experiencing could be a marker of AHI and he refrained from having unsafe sex with his boyfriend until he had a viral load test.
While a third went to a clinic seeking to be tested, but the staff was ignorant of AHI and tried to administer a standard ELISA screen rather than a PCR test which might have detected the virus.
Other participants said the providers they saw downplayed the importance of flu-like symptoms and the need to make a diagnosis of AHI, perhaps because there are no guidelines for treatment at that point in infection.
Dr. Remien asked, "How do we create messages about 'don't screw with the flu,' especially during flu season."
Behavior Change
A number of studies are reporting growing evidence of serosorting; that once people learn that they are HIV-positive; they tend to have sex with other people who are positive. The University of California, San Francisco's Wayne Steward, PhD, looked to see if that was happening among this group of people, and it was.
"There is a significant decline in the number of partners over time" and an increase in the portion of acts that used condoms, he said. "The second trend is an increase in the proportion of partners who are HIV-positive; after diagnosis the majority were HIV-positive…and almost all of their risk behavior – unprotected sex – is with people who they believe to be HIV-positive."
The participants reported two reasons for their change in behavior. One was altruistic, they did not want to put others at risk. The other was more personal; they believed that another HIV-positive person could better understand what they were going through. Steward concluded, "Diagnosis itself is likely to be an important component of risk reduction."
How difficult will it be to identify AHI? Perhaps not that difficult if you know what to look for, said Peter Kerndt, MD, with the Los Angeles County Department of Health Services. "It turns out that the needles are a lot bigger and the haystack a lot smaller than I had thought. It clearly is possible."
Flu-like symptoms, often with a rash, are easily mistaken for something other than HIV infection. That is why risk of exposure 7-11 days prior is important in helping to decide whether or not to use the more expensive PCR assay that looks for the virus itself, rather than the traditional ELISA screening assay that looks for antibodies.
Testing of pooled blood samples, particularly from STD clinics, is another way to identify early infection, even before the onset of symptoms. The state of North Carolina pioneered the idea. Kerndt said Los Angeles County has identified 35 such individuals since beginning their program. New York City began to do so this past summer, and other jurisdictions are starting as well.
He said it is important that both high risk individuals and health care providers become educated about AHI, to help break the chain of new infections. He recommends that gay men who present with symptoms or for STD screening, and who have had a recent high risk sexual exposure should be tested with a PCR test on either an individual or pooled basis.
