Transmission in Prostitutes

“A subset of 140 women out of a total of over 2000 participants from the Pumwani Sex Worker cohort have been identified to be relatively resistant to HIV-1 infection. Previously described resistance mechanisms, such as ?-32-CCR5 polymorphisms, have been discounted in this population as their cells are readily infected in vitro and this genotype has not been detected in this group…39 women were included in the study…HIV-1-resistant (HIV-R [HIV-negative and under study for more than 3 years], n=10 [i.e. 10 women in this group]), HIV-1-negative (HIV-N [HIV negative and under study for less than 3 years], n=10), HIV-1-positive (infected) sex workers (HIV-P, n=10), and HIV-1-uninfected women from the Mother to Child Transmission cohort (MCH, n=9) which were included as an additional low risk of infection, HIV-1-uninfected control group. All of the women from the sex worker cohort were actively engaged in sex work at the time of sample collection…The average age for the HIV-R group was 40.6±5.2 years; HIV-P group 36.5±5.3 years; HIV-N group 30±6.83 years; and MCH 39±4.5 years…Eight proteins were overexpressed and nine were underexpressed in the HIV-R group…[There is no mention of disease in the HIV-positive women. This therefore is evidence that HIV seropositivity is not associated with sexual transmission, and that HIV seropositivity is not proof that disease will follow]”

“Data were from a prospective cohort study of 1206 HIV-1 seronegative sex workers from Mombasa, Kenya who were followed monthly…233 women acquired HIV-1 (8.7/100 person-years)…In multivariate analysis, including adjustment for HSV-2, HIV-1 acquisition was associated with use of oral contraceptive pills [adjusted hazard ratio (HR), 1.46] and depot medroxyprogesterone acetate [aka DMPA or Depo-Provera, a contraceptive providing 3 months protection with each injection] [This could indicate that these chemicals are increasing the risk of false positive HIV tests]”

“Despite an association between bacterial STIs and acquisition of HIV-1 infection, the addition of monthly azithromycin prophylaxis to established HIV-1 risk reduction strategies [among Kenyan prostitutes] substantially reduced the incidence of STIs but did not reduce the incidence of HIV-1. Prevalent HSV-2 infection may have been an important cofactor in acquisition of HIV-1.”

“In this study, the authors…recorded information on prostitute women identified by police and health department surveillance in Colorado Springs, Colorado, from 1967 to 1999…They identified 117 definite or probable deaths [about double the rate that would be expected compared to the general population]…Violence and drug use were the predominant causes of death, both during periods of prostitution and during the whole observation period…Deaths from acquired immunodeficiency syndrome occurred exclusively among prostitutes who admitted to injecting drug use or were inferred to have a history of it.”

“The maintenance of seronegativity despite exposure to HIV has been observed in sexual partners of HIV infected persons [7 references given], infants born to HIV-infected mothers [3 references], commercial sex workers [4 references] and health care workers occupationally exposed to HIV-contaminated body fluids [2 references]”

“some sexual behaviour variables, such as prostitution, appeared to be significant predictors of HIV seropositivity only among men”

“Female sex workers enrolled in the Pumwani Sex Worker Cohort in Nairobi, Kenya were the source of HIV-1-resistant and HIV-1- infected subjects for the studies described here…24 women who were classified as resistant to HIV_1 were available to participate in these studies. All were HIV-1 antibody negative by both enzyme immunoassay and immunoblot. Negative serology on each individual was performed 8-56 times over 4-10 years. All women were HIV-1 PCR negative on specimens obtained simultaneously with the studies reported here. None of the HIV-1-resistant women participating in the present study have subsequently seroconverted to HIV-1 in an additional 24 months of follow up, despite continued exposure to HIV-1 through sex work…These women have intense exposure to HIV-1 through their occupation and, although condom use is frequent (> 80% of sexual encounters), their risk of acquiring HIV-1 infection is enormous. Despite this intense exposure of up to 500 unprotected sexual exposures to HIV-1-infected clients, a small number (13% of initially HIV-1 seronegative women) remain HIV-1 uninfected for prolonged periods (up to 13 years).”

“26 HIV-1-resistant sex workers and 16 HIV-1-infected sex workers were enrolled…A well-defined CD8+ lymphocyte [white blood cell] population was present in all samples…No differences were noted…according to HIV-1 infections status…No association was found between cervical or systemic [i.e. blood] responses [on an HIV-1-specific ELISPOT antibody test] and total CD4+ or CD8+ lymphocyte counts in either HIV-1-resistant or HIV-1-infected subjects. Neither systemic nor mucosal HIV-1-specific IFN-gamma responses were associated with sexual risk behaviors as reported by study subjects at the time of study enrollment, including number of clients per day, duration of sex work, or frequency of condom use [women with sexually transmitted infections were excluded from this study]”

“No correlation was found between the presence of HIV-1-specific IgA [antibodies] in the genital tract of resistant sex workers and immunologic parameters (CD4+ or CD8+ T-lymphocyte counts), behavioural factors (duration of prostitution, frequency of condom use, number of clients per day, or type of contraceptive use), or demographic factors (age).”

“The study participants were selected from women in the Pumwani sex-worker cohort in Nairobi, Kenya, which was established in a collaboration between the Universities of Nairobi and Manitoba in 1985, as described. The 'resistant' women are defined as those remaining seronegative for >3 yr of follow-up. They remain healthy and persistently seronegative for HIV-1 (ELISA for HIV-1/2/0, Murex); repeated testing for HIV-1 proviral DNA by PCR (using specific primer sets for HIV-1 env , nef , and pol ) has always been negative…The extent of exposure, daily over many years, and the diversity of potential infecting strains of HIV are certainly the greatest reported anywhere in the world…The CTL [cytotoxic lymphocyte] studies reported here used a very sensitive technique for eliciting memory peptide-specific CTL, which generated HIV-specific CTL from just under half the women studied; however, this is likely to be an underestimate [the researchers may be biased towards this assumption, as otherwise their investigations into CTL types may be seen as a dead end].”

“Some sex workers and homosexual men remain uninfected despite repeatedly having unprotected sexual intercourse with HIV-infected partners”

“[This study involved] a group of repeatedly exposed but persistently seronegative female prostitutes in The Gambia, West Africa…The seronegative women in this study have worked as prostitutes for more than five years, use condoms infrequently with clients and only rarely with their regular partners, and have a high incidence of other sexually transmitted diseases”

“Human immunodeficiency virus (HIV) prevalence was studied in an unselected group of 216 female and transsexual prostitutes…All 128 females who did not admit to drug abuse were seronegative; 2 of the 52 females (3.8%) who admitted to intravenous drug abuse were seropositive.”

“In 85% of these infected couples, only one member was HIV-1 seropositive despite repeated unprotected sex...A correlation between a recent history of having had sex with a prostitute and HIV-1 seropositivity could not be demonstrated in men who did not have a past history of GUD [genito-urinary disease]”

“In order to determine whether prostitutes operating outside of areas of high drug abuse have equally elevated rates of infection, 354 prostitutes were surveyed in Tijuana, Mexico…None of the 354 [blood] samples…was positive for HIV-1 or HIV-2…Condoms were used…for less than half of their sexual contacts. Only 4 female prostitutes (1%) admitted to ever having abused intravenous drugs. Infection with HIV was not found in this prostitute population despite the close proximity to neighboring San Diego, CA, which has a high incidence of diagnosed cases of AIDS, and to Los Angeles, which has a reported 4% prevalence of HIV infection in prostitutes.”

“No client of a prostitute in London has been found to be positive for antibodies to HIV at the [Praed Street] clinic [as of September, 1988]”

“HIV infection in non-drug using prostitutes tends to be low or absent, implying that sexual activity does not place them at high risk, while prostitutes who use intravenous drugs are far more likely to be infected with HIV...The prevalence of HIV antibodies among prostitutes ranges between zero and 65 per cent, with the single most important risk factor in the US being intravenous drug use. For example, a large multicenter collaborative study found that of 62 women who were HIV-seropositive, 76 per cent had injected drugs. The highest rate of seropositivity for all centers occurred in New Jersey, which is an area of high drug use; here the rate of seropositivity among 56 women prostitutes was 57 per cent. Another cross-sectional study found that among 535 practicing prostitutes in Nevada, 7 per cent of whom admitted to intravenous drug use, none were positive. In contrast, 370 incarcerated prostitutes, all of whom had used drugs intravenously, had a seropositive rate of 6.2 per cent. Other prostitute studies tend to be small but similarly emphasize the central role of drug use as a major risk factor: in New York City, 50 per cent of 12 drug users were positive, compared with 7 per cent of 65 nonusers; in Italy, 59 per cent of 22 drug users were positive, whereas non of the nonusers were. None of the 50 prostitutes tested in London, 56 in Paris, or 399 in Nuremberg were seropositive.”