High incidence of STIs in HIV-positive young American women

Many HIV-positive young women and adolescent girls are diagnosed with a sexually transmitted infection (STI) after their HIV diagnosis, according to American research published in the October edition of the journal Sexually Transmitted Infections. The researchers, from Johns Hopkins University in Baltimore, found that a significant proportion of the girls and women contracting an STI had a plasma viral load high enough to pose a risk of HIV transmission.

The prevalence and incidence of HIV infection among adolescent and young adult women is increasing in the USA and most HIV-infected individuals remain sexually active after their HIV diagnosis.

Investigators therefore wished to determine the incidence of new sexually transmitted infections in HIV-positive adolescent girls and young women aged 13 – 24. They also wished to establish the association between viral load and incident STIs to see if infections were occurring in patients likely to transmit HIV.

A total of 143 individuals, who were receiving care at centres participating in Adolescent HIV Trials Network (ATN) sites, were included in the investigators’ analysis. At baseline demographic details and information on viral load were obtained. At quarterly intervals over 18 months, the researchers gathered information on new STI diagnoses (gonorrhoea, chlamydia, trichomonas and syphilis) and viral load. The investigators did not include herpes or genital warts in their analysis because of the difficulty determining if diagnoses represented new infections or a recurrence of a pre-existing infection.

Reflecting the demographics of heterosexual HIV infection in the USA, the study participants primarily came from minority groups, with 75% being black, 18% Hispanic and 7% white. Mean baseline viral load was 67,000 copies/ml.

It is thought that sexual transmission of HIV rarely occurs when an individual has a plasma viral load below 1,500 copies/ml, but 73% of the adolescent and young women in this study had a viral load above this level. Mean baseline CD4 cell count was 428 cells/mm³. The investigators did not provide information on the number of patients who were taking antiretroviral therapy.

During the 18 months of the study, 27 (19%) women were diagnosed with an STI. The majority of these STIs (19, 70%) were diagnosed in women with a viral load above the transmission threshold of 1,500 copies/ml.

The incidence of STIs was 1.4 per 100 person months for the entire cohort, but 1.6 per 100 person months for those with a viral load above 1,500 copies/ml compared to 1.3 per 100 person months for those with a lower viral load. However, the investigators calculated that incidence of STIs between women with higher and lower viral loads was not statistically significant.

“This work demonstrates that many HIV-positive adolescent girls in care will be diagnosed with at least one STI during an 18 month period and that they acquire STIs at times when they are at a high as well as a low likelihood of HIV transmission based on viral load status”, write the investigators.