Data on HIV Infection in Women Expands
Information presented at ICAAC underscored a need for further study of the interrelation between HIV and STDs.
Because behaviors that lead to HIV infection are generally the same ones that lead to other sexually transmitted diseases, the diagnosis of an STD can be a sign of potential HIV infection.
Ulceration, lesions and other detrimental effects of STDs can increase the susceptibility to HIV infection. Also, because of its profound impact on the immune system, HIV can facilitate recurrence and acquisition of other STDs.
STDs and HIV
Researchers have found significant associations between STDs and HIV, and among them, their common mode of transmission.
In a randomized trial in Uganda, Dr. R.H. Gray and colleagues assessed the effects of STD treatment in the community (Abstract 651). A sub-study evaluated pregnancy outcome and mother-to-child HIV transmission. A total of 3,396 women participated in the study.
Treatment for STDs with the antibiotics azithromycin, cefixime and metronidazole, at different times of gestation, was received by 1,735 participants in the intervention group. The control group included 1,661 participants who received placebo (iron folate). Women who tested positive for syphilis were treated with benzathine penicillin in both groups. Women and infants were observed after delivery and followed long term.
Genital infections were significantly fewer in women who received intervention when compared to the control group. The number of HIV-infected mothers was higher among women in the intervention arm (2.6 percent vs. 1.9 percent in the control group). The incidence of mother-to-child transmission of HIV was also higher (15.6 percent) in children born to women who received intervention compared to women in the control arm (14.6 percent). The rates of syphilis were equal in both groups. Rates of bacterial vaginosis (BV) were high in both groups but slightly lower in women who received treatment. GC ophthalmia (inflammation of the eye, transmitted by a mother who has gonorrhea) and birth weight were significantly reduced in infants born to women who received intervention.
Researchers concluded that treatment of STDs through single-dose antibiotics at any time in pregnancy reduces maternal and infant STDs and improves pregnancy outcomes but does not reduce HIV infection in women.
Why did STD treatment not reduce maternal HIV infection? Researches believe that the impact of HIV disease in these women was so severe (high viral loads and lack of anitiretroviral treatment) that treatment of STDs did not reduce HIV infection.
HIV & HSV-2
Even though Herpes Simplex Virus-2 (HSV-2) is the major cause of genital ulceration worldwide, its role has not been assessed.
A study conducted in the Central African Republic examined how much virus is secreted by the cervix, in women with and without HIV infection (Abstract 1407). Of 300 women tested, 26 percent were HIV-infected, and within this group 92 percent were HSV-2 seropositive. In the group of HIV negative women, 79 percent were found to be HSV-2 seropositive. Likewise, 43 percent of HIV-positive women had detectable virus in cervico-vaginal samples (CVS) by DNA PCR, compared to 22 percent of HIV-negative women that had HSV-2 genital shedding. This result shows that the HSV-2 genital shedding level was higher in HIV-positive women than in HIV-negative shedders.
The study also measured HIV viral load levels in plasma and in CVS of women who did not have contamination with semen from a potentially HIV-infected partner. There was no difference in the HIV viral load in CVS between HIV-2 shedders and non-shedders.
The researcher concluded that there was a high incidence of HIV and HSV-2 in this population. HSV-2 may be an important co-factor of heterosexual female-to-male transmission in areas where both infections (HIV and HSV-2) often occur.
This study did not address the incidence of neonatal herpes in this population even though it is a relatively common disease. It was also concluded that the impact of HSV-2 in newborns needs to be assessed when dealing with immunocompromised women who receive no treatment and have high incidence of HSV-2 shedding.
HIV in the Female Genital Tract
An interesting study conducted in Africa enrolled 1,078 sex-workers highly exposed to HIV through sexual intercourse (Abstract 582).
The objective of the study was to evaluate mucosal immunity to HIV. High levels of HIV antibodies were reported in the genital tract of HIV-resistant Kenyan sex-workers with no evidence of HIV viral load in the plasma. A total of 657 were found to be HIV-positive and 421 were HIV-negative. Cervical vaginal secretions (CVS) were obtained from 342 uninfected women.
This population had a high incidence of STDs. CVS were tested for anti-gp160 antibodies. The antibodies are part of an immune response to HIV and are found in vaginal fluids free of contaminated semen.
There were no detectable levels of HIV viral load in plasma in the 25 women who had anti-gp160 antibodies present. There was no seminal contamination of CVS in only 10 of the 342 HIV negative women. CVS obtained from these women were extensively studied and found to have high levels of HIV antibodies.
Researchers found that only 7.5 percent in a population of 342 HIV-exposed women had HIV antibodies in their genital tract. These observations suggest that those women who did not show evidence of semen from a potentially infected partner, had a compartmentalized immune response without becoming infected. These findings indicate that mucosal immunization with wild-type HIV seems to occur at low levels in highly HIV-exposed populations. This is an area of significance in the development of an HIV vaccine.
HIV in Cervicovaginal Secretions
Two African studies compared the amount of HIV found in the female genital tract using different methods to detect virus in CVS (Abstract: 1579).
Prior investigation shows that plasma and genital viral loads can be different. Researchers obtained several consecutive CVS samples from 55 HIV-infected women. Among the 55 participants, 16 percent were not receiving antiretroviral therapy, 75 percent were on HAART, and 9 percent were only on NRTIs. Investigators obtained virus from the endocervical fluid with a Sno-strip wicking device (cotton pad that collects a certain amount of fluid). They also obtained endocervical cells with a cytobrush (a brush specifically designed to collect cells). The third and last method was a cervicovaginal lavage (CVL) used to detect free virus in the vagina.
Among 363 samples collected by researchers, the virus was present in 48 percent of endocervical fluid samples, 53 percent of endocervical cells, and 34 percent of CVL samples.
Investigators concluded that samples obtained from the endocervical cells were more sensitive and more stable than CVL for assessing the viral load levels in the genital tract.
Liliana Eagan supervises AIDS Project Los Angeles' HIV Resource Center. She can be reached at (323) 993-1484 or by e-mail at firstname.lastname@example.org.
This article has been reprinted at The Body with the permission of AIDS Project Los Angeles (APLA).
This article was provided by AIDS Project Los Angeles. It is a part of the publication Positive Living.