Diagnostic utility of immune-complex-dissociated p24 antigen detection in perinatally acquired HIV-1 infection in Rwanda

We evaluated the diagnostic utility and prognostic value of immune-complex-dissociated (ICD) HIV-1 p24 antigen detection in a prospective cohort study of perinatally acquired HIV-1 infection in Butare, Rwanda. HIV-1 p24 antigen was measured after acid dissociation in plasma samples collected at 6 weeks and 3 months of age from 36 HIV-1 infected and 80 uninfected children born to HIV-1 infected women. Among children with persistent HIV-1 antibody after 12 months of age, 26.7% of samples tested ICD HIV-1 p24 antigen positive. Among children who died between 3 and 12 months of age but were classified as HIV-1 infected, 17.6% tested p24 antigen positive at 6 weeks of age and 33.3% at 3 months of age. Female infants were more likely to test p24 antigen positive than male infants (p = 0.046). The specificity of the assay was 96.8%. Cumulative probabilities of child survival to 36 months of age were computed by HIV-1 status of the child and early p24 antigenemia. The mean survival time was 7 months for HIV-1 infected children with a high (> 50 pg/ml) p24 antigen concentration versus 20 months for children with p24 antigen concentrations between 10 and 50 pg/ml (p = 0.02). Cumulative probabilities of survival to 36 months of age were 0% among HIV-1 infected children with at least one positive p24 antigen test, 44% among confirmed HIV-1 infected children who were p24 antigen-negative at both 6 weeks and 3 months of age, and 95% among seroreverting children (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Incident HIV-1 infection in a cohort of young women in Butare, Rwanda

OBJECTIVE

To determine the incidence of HIV-1 infection and associated risk factors among young, seronegative, and sexually active women in a mixed rural and urban population in southern Rwanda.

DESIGN

A prospective cohort study.

METHODS

Between October 1991 and April 1993, we completed a 2-year follow-up survey among HIV-1-seronegative women aged < or = 30 years at the time of their initial HIV-1 screening during pregnancy. All women aged < or = 25 years and a randomly selected sample of 26-30-year olds were invited to participate from five prenatal clinics in the Butare region. The interview focused on potential risk factors for HIV-1 acquisition during the 2-year interval between blood collection.

RESULTS

Out of 1524 women selected, 1150 (75%) participated in the follow-up survey. The 2-year incidence of HIV-1 infection was 2.7% [95% confidence interval (CI), 1.8-3.9]. Teenage women were at the highest risk (incidence, 10.5%; 95% CI, 5.2-19.4), with incidence leveling off with increasing age (P < 0.001). Women who began sexual activity recently were also at higher risk; the lowest risk category consisted of women aged 26-30 years with 5 or more years of sexual experience. The more urban the geographic residence of the woman, the more likely she was to have acquired HIV-1 infection (P < 0.001). In the urban and peri-urban zones, the poorest women were at significantly higher risk of incident HIV-1 infection than women reporting higher household income. In a multivariate analysis, young maternal age, marital status (being single, divorced or widowed), multiple sexual partners, and a history of sexually transmitted diseases remained strongly associated with incident HIV-1 infection. Geographic residence, hormonal contraception, and receipt of injections were no longer significantly associated with incident HIV-1 infection when these other factors were accounted for simultaneously.

CONCLUSION

Among young Rwandan women, the early years of sexual activity are particularly dangerous for acquisition of HIV-1 infection. Interventions should focus on young teenagers before they become sexually active.

Risk factors associated with prevalent HIV-1 infection among pregnant women in Rwanda. National University of Rwanda-Johns Hopkins University AIDS Research Team

This study evaluated risk factors associated with prevalent HIV-1 infection among pregnant women in a semi-rural but densely populated area surrounding the town of Butare in Rwanda. Overall seroprevalence was 9.3% in 5690 pregnant women who sought antenatal care at one of five health centres. Factors associated with higher seroprevalence of HIV-1 included history of multiple sexual partners, history of at least one sexually transmitted disease (STD), relatively high socioeconomic status (SES), being unmarried, young age at first pregnancy, and low gravidity. Women who had used oral contraceptives, smoked more than one cigarette per day, whose partners were circumcised, and had had sex to support themselves were also at higher risk of being infected. A history of blood transfusion in the past 5 years was not associated with HIV-1 infection. History of multiple sexual partners, history of STD, high household income, partner circumcision, and past oral contraceptive use remained strongly associated with HIV-1 infection even when simultaneously controlling for other covariates. Among legally married women who lacked sexual behaviour risk factors, history of STD, high SES, young age at first pregnancy, and low gravidity were significantly associated with HIV-1 seroprevalence.

Maternal human immunodeficiency virus 1 infection and intrauterine growth: a prospective cohort study in Butare, Rwanda

A prospective cohort study of 318 human immunodeficiency virus 1 (HIV-1)-infected and 309 seronegative pregnant women was carried out in Butare, Rwanda. Birth weight was significantly lower among singleton infants born alive to HIV-1-infected mothers compared with those born alive to seronegative mothers (2706 g vs. 2825 g; P = 0.002). Crown-to-heel length, head circumference, chest circumference and placental weight were also reduced. Maternal HIV-1 infection was significantly associated with intrauterine growth retardation but not with preterm birth. Differences in the body mass index and weight/head ratio suggest that the adverse impact on live born infants may have been most severe towards the end of pregnancy, resulting in a lean infant with a relatively large head. The higher frequency of intrauterine growth retardation could not be explained by potential confounding factors such as maternal cigarette smoking, history of sexually transmitted diseases or sociodemographic characteristics. The neonatal physical examination did not reveal any differences in clinical signs or symptoms within 48 hours of birth except for the presence of conjunctivitis which was more common among infants of HIV-1-infected mothers. The perinatal and neonatal mortality rates were not significantly affected by maternal HIV-1 status.

Multiple sexual partners and mother-to-child transmission of HIV-1

OBJECTIVE

To investigate risk factors for mother-to-child transmission of HIV-1, particularly sexual behavior before and during pregnancy.

DESIGN AND METHODS

This study is part of a prospective cohort study in Butare, Rwanda, of 318 HIV-1-seropositive and 309 HIV-1-seronegative women enrolled during pregnancy and followed for a mean duration of 21 months (range, 8-34 months). Clinical follow-up of the mother-infant pairs was performed at 6-week intervals during the first year of life and at 4-month intervals thereafter. Detailed sexual history interviews were conducted during pregnancy and at the first postnatal visit.

RESULTS

Of 184 singleton infants born to HIV-1-infected mothers who survived the neonatal period, 32 (17%) children were classified as HIV-1-infected, 130 (71%) as not infected, and 22 (12%) died with indeterminate HIV-1 infection status. The vertical transmission rate was estimated to be between 20 and 29%. Unprotected sexual intercourse with increased number of partners during the past 5 years was strongly associated with mother-to-child transmission (P < 0.001), even after adjustment for maternal CD4/CD8 ratio, parity, history of sexually transmitted diseases, and evidence of genital infection during pregnancy. In a multivariate analysis, excluding children with indeterminate HIV-1 status, odds ratios for vertical transmission were 2.6 [95% confidence interval (CI), 1.0-6.9] for maternal CD4/CD8 ratio < 0.5 and 3.6 (95% CI, 1.1-11.8) for more than three sexual partners versus a single partner. Women with more than one sexual partner during the first trimester of pregnancy were at particularly high risk of transmitting the virus.

CONCLUSION

Unprotected sexual intercourse with multiple partners before and during pregnancy in a population with high HIV-1 seroprevalence may well increase the likelihood of HIV-1 transmission from an infected mother to her child.