Seroincidence of HIV-1 infection in African women of reproductive age: a prospective cohort study in Kigali, Rwanda, 1988-1992.

OBJECTIVE: To estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda. DESIGN: Fixed prospective cohort followed for 36 months between November 1988 and June 1992, as part of an ongoing study of mother-to-child transmission of HIV-1. SETTING: Centre Hospitalier, Kigali, Rwanda. SUBJECTS: A total of 216 HIV-seronegative women were enrolled at delivery between November 1988 and June 1989. METHODS: A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. Incidence density rates of HIV seroconversion were estimated. RESULTS: The follow-up rate after 3 years was 89%, assessed by the maximum person-years method. The seroincidence density rate was 3.5 per 100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up. Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counselling, and the first 6-month postpartum effects on this estimate. CONCLUSION: This fixed cohort provided an overall estimation of the HIV infection incidence rate and its dynamics. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.

PIP: The objective was to estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda. A fixed prospective cohort followed a total of 216 HIV-seronegative women for 36 months between November 1988 and June 1992 at Centre Hospitalier, Kigali, Rwanda. A study of mother-to-child transmission of HIV-1 has been going on at the Centre Hospitalier de Kigali since November 1988. A group of HIV-seronegative women matched by maternal age and parity was consecutively selected as a comparison group. The mean maternal age was 25.1 years (SD, 4.5 years), and the total number of pregnancies was 2.7 (SD, 1.8). A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. The follow-up rate after 3 years was 89.2% (577/646.75), assessed by the maximum person-years method. 20 seroconversions were documented during the first 36 months of follow-up among the 216 women seronegative at inclusion, yielding a cumulative incidence of 11.2%. The largest number of seroconversions (8/20; 40%) was observed in the first 6 months of the postpartum period. The seroincidence density rate was 3.5/100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up (P = 0.01). Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counseling, and the first 6-month postpartum effects on this estimate. The study confirms that pregnant women may represent a population in which the HIV seroincidence is high and concentrated in the immediate postpartum period. Pregnant women should become a potential target group for future large scale vaccination trials and programs with adequate follow-up. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.

Maternal plasma viral load, zidovudine and mother-to-child transmission of HIV-1 in Africa: DITRAME ANRS 049a trial.

OBJECTIVE: To study the relationship between maternal plasma RNA levels and mother-to-child transmission (MTCT) of HIV-1 in African breastfed children. DESIGN: Nested case-control study within a randomized trial assessing the efficacy of a short maternal zidovudine (ZDV) regimen to reduce MTCT. METHODS: Eligible women received either 300 mg of ZDV twice a day until labour, 600 mg at the beginning of labour and 300 mg twice a day for 7 days post-partum or a placebo. The diagnosis of paediatric HIV-1 infection was based on PCR tests at days 1--8, 45, 90 and 180 then on serology performed at 3 monthl intervals. Plasma HIV-1 RNA was measured at inclusion and on day 8 after delivery for all women who did transmit HIV to their children (cases) using a Chiron branched DNA assay (sensitivity 50 copies/ml) and compared with women who did not transmit (two per case) matched for phase trial, treatment allocation and site. RESULTS: At inclusion, mean log10 viral load was 4.6 among 55 transmitting mothers and 3.7 among 117 non transmitters (P = 0.0001). Among transmitters, the mean difference in log10 viral load between day 8 post-partum and inclusion was -0.13 in the ZDV group (n = 23) versus 0.27 in the placebo group (n = 32; P = 0.01); among non transmitters it was -0.35 for the ZDV group (n = 47) versus 0.27 in the placebo group (n = 70; P < 10(-4)). In multivariate logistic regression analysis, odds ratios for MTCT were 8.7 (95% confidence interval, 3.7-20.6) for 1 log(10) increase of maternal RNA at inclusion and 4.2 (95% confidence interval, 1.7--10.3) for 1 log(10) increase difference from inclusion to day 8 post-partum. CONCLUSION: High maternal viral load at inclusion strongly predicts MTCT of HIV in Africa. A short ZDV treatment regimen decreases significantly maternal viral load from its pretreatment level.

An assessment of the timing of mother-to-child transmission of human immunodeficiency virus type 1 by means of polymerase chain reaction.

To approximate the contributions of in utero, intrapartum, and postnatal transmission of human immunodeficiency virus type-1 (HIV-1) and to evaluate polymerase chain reaction (PCR) as a diagnostic tool for pediatric HIV infection, blood was collected at birth (cord blood), and at 3, 6-12, and 13-24 months in 218 children born to HIV-1-seropositive mothers in Kigali, Rwanda. Proviral DNA was detected by a double PCR using two sets of three primers (gag, pol, and env). Pediatric HIV-1 infection was defined according to serological and clinical criteria. The probability of having a positive PCR at a given time was calculated by a nonparametric method. Among children with unequivocal evidence of infection (n = 47), it was 30.5% on cord blood and 80.6% at 3 months. Thus, in children born to HIV-1-infected mothers, the estimated rate of transmission in the late postnatal period is 4.9%, and the rate of transmission in the intrapartum plus postnatal periods is 17.6%. Among 117 HIV-1-uninfected children born to HIV-1-infected mothers, six (5%) had a false-positive PCR on cord blood. These results should be taken into account in designing intervention trials aimed at reducing mother-to-child transmission of HIV-1.

Biological markers associated with prolonged survival in African children maternally infected by the human immunodeficiency virus type 1.

Sixteen children over the age of 5 years (Group 1) have been identified out of 537 children infected by human immunodeficiency virus and born to HIV-infected mothers, in Kigali, Rwanda. They were followed up for 2 years and compared with 16 younger AIDS patients (Group 2) and with 16 age- and gender-matched HIV-1 seronegative children (Group 3). Fourteen Group 1 subjects had anti-HIV-1 IgM which persisted during the entire study period, in 11 cases directed to HIV-1 envelope proteins. In vitro, immortalization of B lymphocytes by the Epstein-Barr virus confirmed a high production of IgM to envelope proteins. All these patients had anti-p 17 IgG which was not observed in 7 patients from Group 2. All 16 children mounted significant titers of neutralizing antibodies to HTLV-IIIB, and, in 8 patients tested, against two other HIV-1 strains, RII and MN. HIV-1-specific major histocompatibility complex (MHC)-restricted cytotoxic T cells were demonstrated in 3 of 5 of the subgroup who were tested. Prolonged survival over 5 years in children with maternally acquired HIV-1 infection is associated with a high titer of neutralizing antibodies, a persistent production of IGM to HIV-1 envelope proteins and of IgG to p 17.

Growth of human immunodeficiency type 1-infected and uninfected children: a prospective cohort study in Kigali, Rwanda, 1988 to 1993.

OBJECTIVE: To compare the anthropometric characteristics of children with and without HIV-1 infection. METHODS: In a prospective cohort study of 218 children born to HIV-1 seropositive mothers and 218 children born to HIV-1 seronegative mothers in Kigali, Rwanda, 3 groups were compared: infected children (n = 46); uninfected children born to seropositive mothers (n = 140); and uninfected children born to seronegative mothers (n = 207). Weight, height and head circumference were measured at birth, every 3 months during the first year of life and every 6 months thereafter. The weight-for-age, height-for-age, weight-for-height and head circumference-for-age mean z scores were calculated. RESULTS: The weight-for-age, height-for-age and head circumference-for-age mean z scores were lower among HIV-infected children than among uninfected ones at each time period. The reduction in the weight-for-age mean z score was the greatest between 12 and 36 months. The reduction in the height-for-age mean z score of HIV-infected children was persistently below 2 SD after 9 months of age. On the other hand the weight-for-height mean z score was not consistently lower in HIV-infected children when compared with uninfected ones. The anthropometric characteristics of uninfected children born to seropositive mothers were similar to those of children born to seronegative mothers. CONCLUSIONS: In this study HIV-infected children were more frequently stunted (low height-for-age) than uninfected ones. Wasting (low weight-for-height) was not common among HIV-infected children.

Natural history of human immunodeficiency virus type 1 infection in children: a five-year prospective study in Rwanda. Mother-to-Child HIV-1 Transmission Study Group.

OBJECTIVE: To compare morbidity and mortality of human immunodeficiency virus type 1 (HIV-1)-infected and HIV-1-uninfected children and to identify predictors of acquired immunodeficiency syndrome (AIDS) and death among HIV-1-infected children in the context of a developing country. DESIGN: Prospective cohort study. SETTING: Maternal and child health clinic of the Centre Hospitalier de Kigali, Rwanda. PARTICIPANTS: Two hundred eighteen children born to HIV-1-seropositive mothers and 218 born to seronegative mothers of the same age and parity were enrolled at birth. OUTCOME MEASURES: Deaths, clinical AIDS, nonspecific HIV-related manifestations, and use of health care services. RESULTS: Fifty-four infected and 347 uninfected children were followed up for a median of 27 and 51 months, respectively. With the exception of chronic cough, the risk of occurrence of nonspecific HIV-related conditions was 3 to 13 times higher in infected than in uninfected children. The recurrence rate and severity of these findings were increased systematically in infected infants. Estimated cumulative risk of developing AIDS was 28% and 35% at 2 and 5 years of age, respectively. Estimated risk of death among infected children at 2 and 5 years of age was 45% and 62%, respectively, a rate 21 times higher than in uninfected children. Median survival time after estimated infection was 12.4 months. Early infection, early onset of HIV-related conditions, failure to thrive, and generalized lymphadenopathy were associated with subsequent risk of death and/or AIDS, whereas lymphoid interstitial pneumonitis was predictive of a milder disease. CONCLUSIONS: In Africa, HIV-1-infected children develop disease manifestations early in life. Specific clinical findings are predictive of HIV-1 disease, AIDS stage, and death. Bimodal expression of HIV-1 pediatric disease is encountered in Africa, as in industrialized countries, but prognosis is poorer. human immunodeficiency virus infection, children, vertical transmission, natural history, Africa.

Primary infections with HIV-1 of women and their offspring in Rwanda: findings of heterogeneity at seroconversion, coinfection, and recombinants of HIV-1 subtypes A and C.

Variation in HIV-1 genomic RNA was studied in seroconversion samples from mother-child pairs from a Rwandan cohort. The mothers (n = 8) were heterosexually infected and their children (n = 6) were vertically infected by breast milk. Five of the children seroconverted within the same 3-month period as did their mothers. Highly homogeneous subtype A V3 and p17gag sequence populations were observed in three mother-child pairs, one of the two nontransmitting mothers, and one child (mean nucleotide distances 0 to 0.9%). Heterogeneous populations of subtype A V3 and p17gag sequences were found in one mother and a mother-child pair (1.4 to 2.8% for V3, 1.0 to 1.9% for p17). The second nontransmitting mother was infected with a heterogeneous AV1-V3/Cp17-p24 recombinant virus population (3. 8% for V3, 2.4% for p17). Finally, in one woman subtype C V3 sequences were observed, in addition to highly homogeneous subtype A V3 and p17gag sequence populations, also found in the child. Coexistence of subtype AV1-V3 and CV1-V3 env sequences in the mother was confirmed in a follow-up sample. The gag gene of both the maternal and the child's virus population represented an A/C recombinant sequence (Ap17/Cp24). An infection with subtype CV1-V3/p17-p24 was found upon testing of three additional participants of the mother-child cohort, indicating that subtype C is present in Rwanda. In conclusion, heterogeneity, coinfection, and intersubtype recombinants are not uncommon in primary HIV-1 infections in Rwanda.

Evolution of human immunodeficiency virus subtype A in women seroconverting post partum and in their offspring post-natally infected by ingestion of breast milk.

The evolution of genomic RNA of human immunodeficiency virus type 1 (HIV-1), subtype A, was studied in three Rwandan mother-child pairs over a period of 12-30 months. In two pairs a homogeneous subtype A V3 sequence population was observed at seroconversion and the virus populations in the children resembled those in the mothers. One of these mother-child pairs was infected with an A/C recombinant virus (Ap17/Cp24). In the third pair, a heterogeneous V3 sequence population was observed in the maternal seroconversion sample but the V3 sequence population in the child's sample was homogeneous. In each individual the intra- and intersample variation (between the seroconversion and follow-up samples) increased over time in both the V3 region and p17gag. Independent evolution for 1-2 years did not abolish the epidemiological relationship between virus populations in mother and child.

Infective and anti-infective properties of breastmilk from HIV-1-infected women.

Human immunodeficiency virus type 1 (HIV-1) is transmitted mainly by cell-to-cell contact. We postulated that transmission of HIV-1 through breastmilk could be favoured by the presence of infected cells, by deficiency of anti-infective substances in breastmilk, or both factors. 215 HIV-1-infected women were enrolled at delivery in Kigali, Rwanda; milk samples were collected 15 days, 6 months, and 18 months post partum. HIV-1 IgG, secretory IgA, and IgM were assayed by western blot, for the latter two after removal of IgG with protein G. In the 15-day and 6-month samples, we sought viral genome in milk cells by a double polymerase chain reaction with three sets of primers (gag, pol, and env). HIV-1 infection in the offspring was defined according to serological and clinical criteria. At 15 days, 6 months, and 18 months post partum, HIV-1 specific IgG was detected in 95%, 98%, and 97% of breastmilk samples, IgA in 23%, 28%, and 41%, and IgM in 66%, 78%, and 41%. In children who survived longer than 18 months, the probability of infection was associated with lack of persistence of IgM and IgA in their mothers' milk (adjusted chi 2 for trend, p = 0.01 for IgM and p = 0.05 for IgA). The presence of HIV-1-infected cells in the milk 15 days post partum was strongly predictive of HIV-1 infection in the child, by both univariate (p < 0.05) and multivariate analysis (p = 0.01). The combination of HIV-1-infected cells in breastmilk and a defective IgM response was the strongest predictor of infection. HIV-1 infection in breastfed children born to infected mothers is associated with the presence of integrated viral DNA in the mothers' milk cells. IgM and IgA anti-HIV-1 in breastmilk may protect against postnatal transmission of the virus.

Mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) and its determinants: a cohort study in Kigali, Rwanda.

The authors report the results of the first 2 years of follow-up of a prospective cohort study on the mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) and its determinants which started in November 1988 in Kigali, Rwanda. The study sample consists of 218 newborns of 215 HIV-1 seropositive women matched to 218 newborns of 216 HIV-1 seronegative women of the same age and parity. They were followed every 2 weeks during the first 2 years of follow-up. HIV-1 antibodies were detected by enzyme-linked immunoadsorbent assay and Western blot at 3-month intervals. Two methods of calculating the mother-to-child transmission rate were used: method 1 combines the information provided by the persistence of HIV-1 antibodies at 15 months of age in children born to HIV seropositive mothers and the excess mortality in this group compared with the cohort of children born to HIV seronegative mothers; method 2 is a case-by-case evaluation of all the children born to HIV seropositive mothers. A logistic regression model was used to study the determinants of transmission. The probability of survival at 24 months of age was 81% (95% confidence interval (CI) 75-86) in children born to seropositive mothers, compared with 95% (95% CI 92-98) in children born to seronegative mothers (p < 0.001). The mother-to-child transmission rate calculated with method 1 was 25.7% (95% CI 18.8-32.5). With method 2, the medium estimate was 24.7%. In the multivariate analysis, a CD4/CD8 ratio < 0.5 was the only maternal factor statistically associated with an increased risk of mother-to-child transmission of HIV-1 (odds ratio = 2.9, 95% CI 1.2-7.2). The authors' findings present evidence for a higher mother-to-child transmission rate of HIV-1 in children born in Rwanda than in industrialized countries.

Similarity in env and gag genes between genomic RNAs of human immunodeficiency virus type 1 (HIV-1) from mother and infant is unrelated to time of HIV-1 RNA positivity in the child.

Variation in the env (V3 region) and gag (p17 region) genes of genomic RNA of human immunodeficiency virus type 1 was studied in three mother-child pairs. One infant was human immunodeficiency virus type 1 RNA positive at birth (pair 114), one became positive 6 weeks after birth (pair 127), and one became positive 30 months after birth (pair 564). The first two children were born to seropositive mothers, and the last child was infected by breast-feeding following seroconversion of the mother after delivery. In both V3 and p17gag, intrasample variability was much higher in the maternal samples, including the first seropositive sample of the seroconverted mother, than in the infants' samples. Variability was less in p17gag than in V3, except in the postnatally infected child. In all three cases, infection of the child was established by variants representing a minority of the cell-free virus population in the maternal samples. For the two infants born to seropositive mothers, V3 sequences were more similar to the sequence populations of maternal samples collected during pregnancy than to those of samples collected at delivery or thereafter. However, in pair 114 a V3 variant identical to the child's virus was also detected in the sample collected at delivery. In contrast to the V3 region, p17gag sequences of maternal samples of the first trimester of pregnancy and at delivery had comparable resemblance to the child's sequences in pair 114, while in pair 127, similarity to sequences of the sample collected at delivery was higher than that to sequences of the sample from early in pregnancy. In the last pair, V3 and p17gag sequences from a maternal sample collected 18 months prior to the first RNA-positive sample of the child resembled the infant's sequences as much as the sample collected close to the presumed time of infection. Taken together, the evolutionary characteristics for genomic RNA env and gag genes did not point to a particular time of mother-to-child transmission.

Four years of natural history of HIV-1 infection in african women: a prospective cohort study in Kigali (Rwanda), 1988-1993.

Clinical features and mortality due to human immunodeficiency virus type-1 (HIV-1) infection in women are described as part of a prospective 4-year cohort study on perinatal transmission of HIV in Kigali, Rwanda. Two hundred fifteen HIV-seropositive (HIV+) and 216 HIV-seronegative (HIV-) pregnant women were enrolled at delivery between November 1988 and June 1989. Clinical information collected during systematic quarterly examinations was compared. HIV antibody tests were performed at delivery and CD4/CD8 lymphocyte counts at 15 days' postpartum. HIV--women who seroconverted during the follow-up period were excluded from the analysis of the comparison group starting at the date of seroconversion. At enrollment, all HIV+ women were asymptomatic for acquired immune deficiency syndrome (AIDS). Incidence of tuberculosis was 2.9 per 100 women-years (WY) after 4 years of follow-up in HIV+ women versus 0.2 per 100 WY among HIV- women (relative risk, 18.2; 95% confidence interval 2.4-137.0). Among HIV+ women, the incidence of AIDS (World Health Organization clinical AIDS definition) was 3.5 per 100 WY. The mortality rate was 4.4 per 100 WY among HIV+ women versus 0.5 per 100 WY among HIV- women. Clinical AIDS was present in only half of the fatalities. Tuberculosis was a major cause of morbidity and mortality in these HIV+ African women. An early diagnosis and an appropriate treatment or prevention of tuberculosis should improve the quality of life of HIV-infected patients in Africa.

Postnatal transmission of human immunodeficiency virus type 1 from mother to infant. A prospective cohort study in Kigali, Rwanda.

BACKGROUND: Although transmission of human immunodeficiency virus type 1 (HIV-1) from mother to infant has been well documented during pregnancy and delivery, little is known about the possible transmission of HIV-1 during the postnatal period. METHODS: We conducted a prospective cohort study in Kigali, Rwanda, of 212 mother-infant pairs who were seronegative for HIV-1 at delivery. All the infants were breast-fed. The subjects were followed at three-month intervals, with Western blot assays for antibodies to HIV-1 and testing of mononuclear cells by a double polymerase chain reaction (PCR) using three sets of primers. To evaluate potential risk factors, each mother who seroconverted was matched with three seronegative control women. RESULTS: After a mean follow-up of 16.6 months, 16 of the 212 mothers became seropositive for HIV-1. Of their 16 infants, 9 became seropositive. One infant was excluded from the analysis because of a positive test by PCR on the blood sample obtained at birth. Postnatal seroconversion to HIV-1 occurred in four of the five infants born to the mothers who seroconverted during the first 3 months post partum, and in four infants of the 10 mothers who seroconverted between month 4 and month 21. In all cases, the infant seroconverted during the same three-month period as the mother. The main risk factor for maternal seroconversion was being single. CONCLUSIONS: HIV-1 infection can be transmitted from mothers to infants during the postnatal period. Colostrum and breast milk may be efficient routes for the transmission of HIV-1 from recently infected mothers to their infants.

6-month efficacy, tolerance, and acceptability of a short regimen of oral zidovudine to reduce vertical transmission of HIV in breastfed children in Côte d'Ivoire and Burkina Faso: a double-blind placebo-controlled multicentre trial. DITRAME Study Group. DIminution de la Transmission Mère-Enfant.

BACKGROUND: Zidovudine reduces the rate of vertical transmission of HIV in non-breastfed populations. We assessed the acceptability, tolerance, and 6-month efficacy of a short regimen of oral zidovudine in African populations practising breastfeeding. METHODS: A randomised double-blind placebo-controlled trial was carried out in public clinics of Abidjan, Côte d'Ivoire, and Bobo-Dioulasso, Burkina Faso. Eligible participants were women aged 18 years or older, who had confirmed HIV-1 infection and pregnancy of 36-38 weeks duration, and who gave written informed consent. Exclusion criteria were severe anaemia, neutropenia, abnormal liver function, and sickle-cell disease. Women were randomly assigned zidovudine (n=214; 300 mg twice daily until labour, 600 mg at beginning of labour, and 300 mg twice daily for 7 days post partum) or matching placebo (n=217). The primary outcome was the diagnosis of HIV-1 infection in the infant on the basis of sequential DNA PCR tests at days 1-8, 45, 90, and 180. We compared the probability of infection at a given age in the two groups. Analyses were by intention to treat. FINDINGS: Women were enrolled between September, 1995, and February, 1998, when enrolment to the placebo group was stopped. Analysis was based on 421 women and 400 lifeborn infants. Baseline demographic, clinical, and laboratory characteristics were similar in the two groups. The Kaplan-Meier probability of HIV infection in the infant at 6 months was 18.0% in the zidovudine group (n=192) and 27.5% in the placebo group (n=197; relative efficacy 0.38 [95% CI 0.05-0.60]; p=0.027). Adjustment for centre, period of recruitment, mode of delivery, maternal CD4-cell count, duration of labour, prolonged rupture of membranes, and duration of breastfeeding did not change the treatment effect. The proportions of women taking more than 80% of the planned maximum dose were 75% before delivery, 81% during labour, and 83% post partum, without statistical difference between the groups. No major adverse biological or clinical event was reported in excess among women and children of the zidovudine group. INTERPRETATION: A short course of oral zidovudine given during the peripartum period is well accepted and well tolerated, and provides a 38% reduction in early vertical transmission of HIV-1 infection despite breastfeeding.