How to recognize and prevent HIV infections
Mr. R, a 22-year-old gay man, presents with a maculopapular rash of broad distribution involving the palms and soles. A review of systems reveals that eight weeks prior to this examination, he had a flulike illness that included fever to 102°F, sore throat, and muscle ache. His primary-care provider, whom he had seen only once before for a school-mandated physical, diagnosed the flu. Three months ago, Mr. R engaged in unprotected receptive anal intercourse with a partner he is “sure” is HIV-negative. Mr. R's rapid plasma reagin test is positive at 1:128, and a rapid HIV test is reactive. He is in disbelief about the results.
Despite widespread knowledge of HIV transmission routes, the incidence of new infections in the United States has remained steady at about 40,000 per year. The CDC estimates that more than 1 million Americans are now living with HIV or AIDS, and perhaps 25% of those infected are unaware of their HIV status. Why are so many people acquiring this preventable virus, and why are so many who have it escaping diagnosis? One reason is that the traditional “risk-based” screening algorithm is flawed, allowing many infected individuals to slip through the cracks.
Although the basic facts about HIV transmission have not changed, new data have emerged. At the 14th Conference on Retroviruses and Opportunistic Infections, which was held in Los Angeles earlier this year, several pertinent studies on transmission were presented. Some illuminated factors that facilitate HIV transmission, while others fortified or discredited various prevention strategies.
Newly infected patients are highly infectious
Patients with acute HIV infection typically experience a burst of viral replication and are thus more likely to transmit the virus to others. In addition, “superinfection” with new strains of HIV is more likely during the early infection period. The combination of these two findings underscores the importance of identifying patients during the acute phase of HIV infection, so they can be properly counseled about sexual behavior, evaluated, and treated.
Asking patients how many sexual partners they have had is admittedly difficult, but this is an important issue. One study found that among recently infected men who have sex with men (MSM), those who have a larger number of partners are more likely to engage in risky behaviors.1 On the other hand, knowledge of one's HIV infection has been linked to a decrease in risky behaviors.2
Diagnosing acute HIV infection
Following infection, a majority of patients (50%-90%) experience a flulike illness characterized by, in order of decreasing frequency, fever, pharyngitis, maculopapular rash, arthralgias, myalgias, and headache. Symptoms usually occur within the first four to six weeks following infection. The nonspecific nature of these symptoms makes it easy to settle on common, less devastating explanations than acute HIV infection.
The best assay to diagnose acute HIV infection is the HIV RNA polymerase chain reaction, since antibody tests may be negative at this stage. No clear evidence to date supports treatment of acute HIV infection, but it is worth considering referral to a center conducting clinical research with these patients.