Rates of herpes simplex virus type 2 (HSV-2) infection were much higher in teens with HIV or with a high risk of HIV than in the general population, according to results of a large study at 15 centers across the United States.1 HSV-2 prevalence, the proportion of teens already infected when they entered the study, was more than 20 times higher in the study group than in the general population. And HSV-2 incidence, the proportion of teens infected with HSV-2 over the course of the study, was more than 40 times higher in the study group than in the general population. Being infected with HIV tripled the risk that a teen would have HSV-2 when entering this study.
HSV-2 infection is one of the most common sexually transmitted infections in the world. A nationwide 2005-2008 U.S. study found that 16% of people 14 to 49 years old had HSV-2.2 HSV-2 rates are usually higher in HIVpositive people, because HSV-2 and HIV are both transmitted during sex. About 60% to 70% of HIV-positive people in the United States may have HSV-2 infection, and that estimate is even higher in African Americans.3
HSV-2 can cause painful sores in genital areas, and these sores can reappear.4 The U.S. Centers for Disease Control (CDC) warns that women should be careful to avoid HSV-2 during pregnancy because the virus can be transmitted to newborns and may sometimes kill a baby.4 A sex partner can give you HSV-2 even if the partner does not have visible herpes sores.
Because little is known about HSV-2 infection rates and risks in teens with HIV and at risk for HIV, researchers at the University of Alabama at Birmingham conducted this analysis in the REACH study group.
This study involved members of the REACH study group who were HIV-negative or were infected with HIV through risky behavior, usually sex. Researchers tested blood samples for HSV-2 when these young people entered the study and again at the end of the study. They also tested blood samples for HIV when teens entered the study and then every 6 months. The analysis did not include anyone who became infected with HIV during the study period.
The researchers used standard statistical methods to identify risk factors for HSV-2 infection by comparing three groups:
The study involved 513 teens -- 386 girls and 127 boys. Of the study participants, 343 (67%) were HIV-positive. Age averaged about 17 years when the study began and did not differ between teens who had HSV-2 when the study started and those who did not.
When the study began, 179 youngsters (about one third) had HSV-2 infection. HSV-2 prevalence (the rate when the study began) was 39% in blacks (138 of 352), 21% in Hispanics (21 of 101), and 17% in whites (4 of 23). Teens who had HSV-2 when the study began were more likely to be heterosexual (81% versus 69%), girls (91% versus 67%), non-Hispanic blacks (78% versus 64%), HIV-positive (82% versus 59%), and also infected with chlamydia, another sexually transmitted infection (25% versus 16%).
Statistical analysis that considered many HSV-2 risk factors identified three factors that raised the odds of HSV-2 when the study began. regardless of what other risk factors a person had (Figure 1). Girls had more than 7 times higher odds than boys, HIV-positive teens had 3 times higher odds than HIV-negative teens, and youngsters still uncertain about their sexual preference had almost 4 times higher odds. Compared with blacks, Hispanics had about 60% lower odds of HSV-2 when entering the study.
Figure 1. Teens with HIV, those still unsure of their sexual preference, and girls had higher odds of HSV-2 infection, a sexually transmitted infection, when entering a large U.S. study.
During almost 2 years, 47 teens became infected with HSV-2. Incidence of HSV-2 (the new infection rate) was 7.35 cases per 100 person-years. HSV-2 incidence was higher in girls (7.70 versus 6.64 per 100 person-years), blacks (7.62 versus 6.89), and teens with HIV (8.50 versus 5.58).
Teens who became infected with HSV-2 during the course of the study were older (19.4 versus 18.8 years), were more likely to drink alcohol (51% versus 32%) or use drugs (57% versus 37%), had more sex partners (average 6.6 versus 3.4), and were more likely to be HIV positive (70% versus 57%). Statistical analysis that factored in several HSV-2 risk factors isolated only one that made new HSV-2 infection more likely, regardless of other risk factors: Using drugs during the study period more than doubled the odds of getting HSV-2 infection during that period.
There were 197 HIV-positive youngsters (124 girls and 73 boys) who started the study without HSV-2 infection. During the study, 33 HIV-positive teens (17% of 197) became infected with HSV-2. The researchers compared these 33 teens with 63 HIV-positive teens who did not get infected with HSV-2 during the study. The HSV-2-positive and negative groups did not differ by age, gender, race, or rates of other sexually transmitted infections.
Compared with HIV-positive teens who remained HSV-2 negative, teens who picked up HSV-2 infection were more likely to trade sex for food, housing, or drugs (15.2% versus 3.2%), had higher CD4 counts (average 569 versus 451), and had lower HIV viral loads (about 3000 versus 8000 copies) when entering the study. Statistical analysis that considered many HSV-2 risk factors found only one that raised the risk of new HSV-2 infection regardless of what other risk factors a person had: Every 50-cell higher CD4 count raised the HSV-2 risk 17%.
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