RISK GROUPS FOR HIV INFECTION
Most patients with unrecognized HIV infection are asymptomatic, and therefore primary care providers must be keenly aware of risk behaviors-and high-risk populations to target HIV testing to the groups in whom it is most needed. Recent studies have consistently shown that at least half of patients at highest risk for HIV perceive themselves to be at low risk, and most have never been tested.
Unprotected Sex and Sharing of Needles
The most important behaviors conferring increased risk of HIV infection are unprotected vaginal, anal, or oral sex (including heterosexual sex) and the sharing of needles for intravenous drug use.
An HIV infection can only be acquired through person-to-person transmission of infected blood, semen, or vaginal fluid. Therefore, the first step in assessing any patient’s risk of HIV infection is directed questioning about any of the above behaviors. Patients with a history of multiple sexual partners or a single reported episode of intravenous drug use are at high risk for HIV infection. In addition, patients who engage in substance abuse of any kind (including non-injection drugs) or trading sex for money or drugs are at high risk for HIV infection. The CDC does not keep statistics on the prevalence of cocaine or crack use among those infected with HIV, so the magnitude of this risk factor is possibly under-emphasized.
Male Homosexual Contact
Almost half of the HIV-infected patients are men having sex with men (MSM). Similarly, an estimated 42% of new HIV infections will occur in this risk group.
While patients in this risk group no longer account for the majority of HIV cases, it is important to note that MSM are still dramatically over-represented in both known and new HIV cases. In some urban populations, the seroprevalence of HIV in MSM has been reported as high as
Recognition and Diagnosis of Human Immunodeficiency Virus Infection
16%. Additionally, the subpopulation of MSM whose prevalence is increasing the fastest is adolescents and young adults, perhaps because they have not seen friends die of AIDS like older generations of MSM have. Some may foster feelings of immortality common to their age group. For these reasons, all MSM should be offered HIV testing at least once. Patients with ongoing risk behaviors should be considered for annual or even semiannual testing.
Heterosexual Contact
About 16% of all currently HIV-infected patients acquired the infection through heterosexual contact. However, one third of new infections will occur in this risk group.
Physicians have been slow to recognize the increasing numbers of patients, particularly women, who acquire HIV infection through heterosexual contact. One survey of patients infected through heterosexual contact showed that only 1.3% had been tested primarily because they were perceived to be in a high-risk group. Therefore, the percentage of newly infected patients in this group continues to rise. Any patient with two or more heterosexual partners (at any time) or a history of unprotected sex with a single partner is at higher risk of HIV infection. This applies to both men and women, although viral transmission is more efficient from men to women than from women to men.
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