Obstetrical factors and the transmission of human immunodeficiency virus type 1 from mother to child. The Women and Infants Transmission Study

Transmission of HIV in the dental clinic and elsewhere

This review focuses on the risk of transmission of HIV in dental practice in developed and developing countries; and as a result of oral sex, perinatal transmission and breast feeding. Postexposure prophylaxis (PEP) and practical measures to control cross-infection with TB are also discussed. There are few data from resource-poor countries where prevalence of HIV and risk of infection are higher--issues that deserve priority. Available information indicates that the risk of HIV transmission in the dental office is very low. Transmission of HIV from three healthcare workers to patients has been confirmed, including a dentist who infected six patients. There are >300 reports (102 confirmed) of occupational transmission to healthcare workers, including nine dental workers (unconfirmed). Exposure to HIV has been reported by 0.5% dentists/year. The risk of HIV infection after percutaneous exposure (0.3%) can be reduced by 81% with zidovudine PEP. However, risk assessment is required to assess the need and appropriate regimen. The risk of HIV transmission associated with orogenital sex exists, but is considered extremely low: barrier protection is recommended. Conversely, the proportion of babies who acquire HIV from untreated HIV-seropositive mothers is 15-25% in developed countries and 25-45% in developing countries. The frequency of HIV transmission attributable to breastfeeding is 16%. Airborne transmission of TB can be avoided by the prompt referral of known/suspected cases of active TB for chemotherapy, deferral of elective procedures until patients are not infectious, and the use of appropriate standard/isolation precautions including adequate ventilation of treatment areas.

Hepatitis C and human immunodeficiency virus infection

In the United States, an estimated 200,000 persons are infected with both hepatitis C virus (HCV) and human immunodeficiency virus (HIV). As the lives of HIV-infected persons have been prolonged by use of highly active antiretroviral therapy, liver disease has emerged as an important, and in some settings, the leading cause of morbidity and mortality. Human immunodeficiency virus infection appears to adversely affect all stages of hepatitis C infection, leading to increased viral persistence and accelerated progression of HCV-related liver disease. In turn, hepatitis C may affect the management of HIV infection, increasing the incidence of liver toxicity caused by antiretroviral medications. The medical management of hepatitis C in HIV-infected persons remains controversial, in part because of the complexity of both infections and potential drug interactions, but chiefly because there is so little published information. Nonetheless, the burden of liver disease is too high to delay management of HIV/HCV-coinfected persons while awaiting better data. Instead, the management of hepatitis C today must be based on data generated on persons without HIV and an understanding of both infections. Properly designed studies of therapy in HIV/HCV-coinfected persons are needed to help guide management of these patients in the future.

Hepatitis C and human immunodeficiency virus infection

In the United States, an estimated 200,000 persons are infected with both hepatitis C virus (HCV) and human immunodeficiency virus (HIV). As the lives of HIV-infected persons have been prolonged by use of highly active antiretroviral therapy, liver disease has emerged as an important, and in some settings, the leading cause of morbidity and mortality. Human immunodeficiency virus infection appears to adversely affect all stages of hepatitis C infection, leading to increased viral persistence and accelerated progression of HCV-related liver disease. In turn, hepatitis C may affect the management of HIV infection, increasing the incidence of liver toxicity caused by antiretroviral medications. The medical management of hepatitis C in HIV-infected persons remains controversial, in part because of the complexity of both infections and potential drug interactions, but chiefly because there is so little published information. Nonetheless, the burden of liver disease is too high to delay management of HIV/HCV-coinfected persons while awaiting better data. Instead, the management of hepatitis C today must be based on data generated on persons without HIV and an understanding of both infections. Properly designed studies of therapy in HIV/HCV-coinfected persons are needed to help guide management of these patients in the future.

A collaborative program between a school of public health and a local health department to increase HIV testing of pregnant women

OBJECTIVE

This study evaluates the effectiveness of a continuing medical education (CME) program that sought to increase HIV testing of women attending maternity clinics of the City of Houston Department of Health and Human Services (HDHHS). The CME program consisted of 14 training sessions given in 1995, 1996, 1997, 1999, and 2000. Educational objectives included increasing patient knowledge of HIV perinatal testing, increasing patient appreciation of the importance of HIV testing, and developing staff skills in educating and counseling women to accept HIV testing during pregnancy.

METHODS

The CME program was based on assessment of clinician learning needs and an algorithm of the testing process, both jointly developed by faculty from the University of Texas Health Science Center at Houston School of Public Health and HDHHS personnel. The algorithm was also used to assess the care delivered. The CME was evaluated by examining changes in the percentage of women tested in the maternity clinics.

RESULTS

In 1995, the year before the education program, 5.7% of women seen in the maternity clinics were tested for HIV. After the program began, testing rates rose to 64.2% in 1996, 65.5% in 1997, and 43.3% in 1998. Given the decline in testing in 1998, additional CME sessions were conducted in 1999-2000. The rate of testing rose to 62.3% in 1999 and 76.5% in 2000.

CONCLUSION

Cooperative planning between university and health department personnel can create CME programs that alter provider behaviors and service delivery patterns to increase HIV testing. Outcomes need to be regularly monitored, however, to determine the need for maintenance or performance reinforcement.

Vertical transmission of human immunodeficiency virus

Sensitive detection methods, such as DNA PCR and RNA PCR suggest that vertical transmission of human immunodeficiency virus (HIV) occurs at three major time periods; in utero, around the time of birth, and postpartum as a result of breastfeeding (Fig. 1). Detection of proviral DNA in infant's blood at birth suggests that transmission occurred prior to delivery. A working definition for time of infection is that HIV detection by DNA PCR in the first 48 h of life indicates in utero transmission, while peripartum transmission is considered if DNA PCR is negative the first 48 h, but then it is positive 7 or more days later [1]. Generally, in the breastfeeding population, breast milk transmission is thought to occur if virus is not detected by PCR at 3-5 months of life but is detected thereafter within the breastfeeding period [2]. Using these definitions and guidelines, studies has suggested that in developed countries the majority, or two thirds of vertical transmission occur peripartum, and one-third in utero [3-6]. The low rate of breastfeeding transmission is due to the practice of advising known HIV-positive mothers not to feed breast milk. However, since the implementation of antiretroviral treatment in prophylaxis of HIV-positive mothers, some studies have suggested that in utero infection accounts for a larger percentage of vertical transmissions [7]. In developing countries, although the majority of infections occurs also peripartum, a significant percentage, 10-17%, is thought to be due to breastfeeding [2, 8, 9].

Mother-to-child transmission of HIV-1: the role of HIV-1 variability and the placental barrier

The acquired immunodeficiency syndrome (AIDS), which is caused by the human immunodeficiency virus (HIV), was first described in the United States of America in 1981 [1]. The worldwide spread of HIV has soon been recognized and AIDS has become one of the most alarming infectious diseases of our days. Its impact has been tremendous, high morbidity and mortality has caused a reversal of socioeconomic gains previously recorded in several developing countries, especially those in Sub-Saharan Africa [2]. Epidemiological data about the HIV and AIDS pandemic are updated by the Joint United Nation Programme on HIV/AIDS, UNAIDS (http://www.unaids.org). Their latest report from December 2000 states that in year 2000 approximately 5.3 million people have become newly infected with HIV, of which 2.2 were women and 600,000 children younger than 15 years of age. The estimated number of people living with HIV/AIDS globally is 36.1 million, of which 16.4 million are women and 1.4 million are children younger than 15 years of age. Approximately 25.3 million (70%) of these HIV infected people live in Sub-Saharan Africa, 5.8 million in South- and South-East Asia (15%), and 1.4 million in Latin-America (5%). During year 2000, 3 million people died of AIDS (1.3 million women and 500,000 children younger than 15 years of age). This means that an estimated total of 21.8 million persons have died of AIDS since the beginning of the epidemic, including 4.3 million children younger than 15 years of age.

Synergism between HIV and other viruses in the mouth

The HIV family replicate in and are shed from the mouth. Oral sexual practices potentially contribute to the overall extent of HIV transmission, particularly if high-risk practices are not restricted. Herpesviruses and papillomaviruses that appear in the oral cavity can determine oral HIV replication. The mechanisms probably include heterologous transactivation, enhanced expression of HIV receptors and co-receptors in target cells, release of cytokines and chemokines, and production of superantigens. Oral diseases peculiar to, or more common in, the HIV-infected patient further predispose to heightened oral HIV replication and trafficking. Defining the mechanisms by which oral viruses interact with HIV in the co-infected host should permit intervention measures against oral HIV transmission to be more precisely targeted.

Association of HIV-1 viral phenotype in the MT-2 assay with perinatal HIV transmission

A case-control design study was used to investigate the association of maternal HIV-1 phenotype in MT-2 cells at or near the time of delivery with perinatal transmission of HIV-1, controlling for maternal CD4 percentage and duration of rupture of membranes, in 48 transmitting and 96 non-transmitting HIV-1-infected mothers who gave birth between 1990 and 1995. The non-syncytium-inducing (NSI) phenotype was more commonly seen in transmitting mothers compared with non-transmitting mothers (90% vs. 75%, p =.04). In a multivariable logistic regression model, the following maternal characteristics were significantly associated with HIV transmission: NSI phenotype (odds ratio [OR] = 6.08; 95% confidence interval [CI]: 1.73-21.35) and log(10) viral load (OR = 2.11; CI: 1.19-3.74). Finally, the association of NSI phenotype with transmission was stronger in transmitting women who received azidothymidine during pregnancy compared with transmitters who did not.

Transmission of HIV-1 from mother to infant

In the developed world, antiretroviral therapy (ART) administered to the mother during pregnancy and intrapartum and to the infant in the neonatal period has resulted in a reduction of the overall risk of vertical transmission of HIV-1 to approximately 8%. In some settings, ART combined with cesarean section and a reduction in duration of ruptured membranes has resulted in a further lessening of risk to levels < or = 2 percent. A number of less expensive and greatly abbreviated ART regimens, useful for application in resource poor settings, also have resulted in reductions of mother-to-infant transmission of HIV-1 by 33 to 50% compared to baseline. A multitude of studies have shown these drugs to be safe for mothers, fetuses, and newborns. Breastfeeding seems to represent a risk factor that adds to the risk of vertical transmission, especially in infants who are fed a combination of breastmilk and other liquids and solids. Studies designed to assess the possible benefits of treating genital ulcer disease, chorioamnionitis, mastitis, and malnutrition in HIV-infected women, and of applying antiseptic washes to the cervix and vagina during labor, are in progress.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

At the end of 2000 it was estimated that over 36 million people were living with the human immunodeficiency virus (HIV). This includes 1.4 million children less than 15 years of age. This is one of several reviews assessing the available evidence for preventing mother-to-child transmission of HIV infection. The other reviews will address other interventions, including Caesarean section, breast feeding, vaginal lavage and vitamin A supplementation.

OBJECTIVES

To assess which antiretroviral therapies may be effective in decreasing the risk of mother-to-child transmission of HIV infection as well as their effect on neonatal and maternal mortality and morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. We also searched conference abstracts from the International AIDS Conferences and Conference on Retroviruses and Opportunistic Infections.

SELECTION CRITERIA

Randomised trials comparing any antiretroviral therapy aimed at decreasing the risk of mother-to-child transmission of HIV infection with placebo or no treatment, or any two or more antiretroviral therapies or regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality.

MAIN RESULTS

Zidovudine monotherapy Any zidovudine regimen versus placebo significantly reduces the risk of mother-to-child transmission (Peto odds ratio (OR) 0.46, 95% confidence interval (CI) 0.35 to 0.60). Zidovudine also appears to decrease the risk of infant death within the first year of birth (OR 0.57, 95% CI 0.38 to 0.85) and the risk of maternal death (OR 0.32, 95% CI 0.16 to 0.66). There is no evidence that zidovudine influences the incidence of premature delivery (OR 0.86, 95% CI 0.57 to 1.29) or low birth weight (OR 0.74, 95% CI 0.53 to 1.04). The risk of transmission using a 'short-short' course of zidovudine (from 35 weeks in pregnancy for the mother and for the baby until 3 days old) was higher than the risk using a 'long-long' course (from 28 weeks in pregnancy for the mother and for the baby until 6 weeks old), (OR 2.55, 95% CI 1.26 to 5.18). However, the effectiveness of the 'long-short' course (from 28 weeks in pregnancy for the mother and for the baby until 3 days old) and the 'short-long' course (from 35 weeks in pregnancy for the mother and for the baby until 6 weeks old) did not differ from that of the 'long-long' course. Nevirapine One large randomised controlled trial demonstrates that nevirapine given to mothers as a single dose at the onset of labour and to babies as a single dose within 72 hours of birth is more effective than an intrapartum and post-partum regimen of zidovudine (OR 0.51, 95% CI 0.33 to 0.79). When nevirapine is given to mothers already receiving standard antiretroviral therapy, however, there appears to be no additional advantage (OR 1.10, 95% CI 0.42 to 2.86). Combination Therapy Preliminary findings of the effect of combination therapy using zidovudine and lamivudine (3TC) suggest a decrease in the risk of transmission when the combination is given during the antenatal and intrapartum period or during the intrapartum and postpartum period compared with placebo. There is no evidence that intrapartum zidovudine and lamivudine alone are sufficient to decrease the risk of transmission compared with placebo.

REVIEWER'S CONCLUSIONS

Implications for practice The randomised trials included in this review provide evidence that short course zidovudine and single-dose nevirapine are effective therapies for reducing mother-to-child transmission of HIV. The challenge for low and middle income countries will be to institute this therapy in practice. In industrialised countries practice has already moved on from the current evidence and combination antiretroviral therapy aimed primarily at preventing disease progression in the mother is the standard of care. Implications for research The potential value of nevirapine used for longer durations in breastfeeding populations should be considered as it may further reduce the risk of mother-to-child transmission, particularly if combined with early weaning. On-going evaluation of combination antiretroviral therapy is essential and will have an immediate benefit for countries with the resources to adopt such treatment. The search for effective, affordable, safe and acceptable alternatives to antiretroviral therapy for reducing mother-to-child transmission in resource poor countries should remain on the research agenda.

Determinants of HIV-1 shedding in the genital tract of women

BACKGROUND

Plasma HIV-1 RNA concentration has been the best predictor for risk of heterosexual and perinatal transmission. However, direct contact with HIV-1 present locally in the genital tract might be necessary for transmission. We aimed to assess the relation between HIV-1 shedding (RNA or culturable virus) in female genital secretions and other factors that might affect HIV-1 shedding.

METHODS

This was a cross-sectional study within the Women's Interagency HIV Study (WIHS), a prospective longitudinal cohort study of HIV-infected women. We enrolled 311 HIV positive women from Jan 30, 1997 to July 1, 1998. We did clinical assessments, cultured HIV-1, and measured RNA in peripheral blood mononuclear cells (PBMC) and genital secretions. We compared the results with univariate and multivariate analyses. Presence of HIV-1 RNA or culturable virus in genital secretions was defined as HIV-1 shedding.

FINDINGS

HIV-1 RNA was present in genital secretions of 57% (152/268) of women whereas infectious virus was detected only in 6% (17/271). Genital tract HIV-1 shedding was found in 80% (130/163) of women with detectable plasma RNA and 78% (116/148) of women with positive PBMC cultures. 33% (27/83) of women with less than 500 copies/mL plasma RNA and 39% (35/90) of those with negative PBMC cultures also had genital tract shedding.

INTERPRETATION

Plasma RNA concentration, both qualitatively and quantitatively, was the most important factor in predicting genital HIV-1 shedding, even among women receiving potent antiretroviral therapy. However, HIV-1 shedding did occur in women with less than 500 copies/mL plasma HIV-1 RNA. This finding suggests that a separate reservoir of HIV-1 replication may exist in some women.

Mother-to-child transmission of HIV infection and CTL escape through HLA-A2-SLYNTVATL epitope sequence variation

Cytotoxic T lymphocytes (CTL) play a central role in containment of HIV infection. Evasion of the immune response by CTL escape is associated with progression to disease. It is therefore hypothesised that transmitted viruses encode escape mutations within epitopes that are required for successful control of viraemia. In order to test this hypothesis, escape through the dominant HLA-A2-restricted CTL epitope SLYNTVATL (p17 Gag residues 77-85 SL9) in the setting of mother-to-child-transmission (MTCT) was investigated. Initial data from two families in which the HIV-infected mother expressed HLA-A*0201 and had transmitted the virus to other family members were consistent with this hypothesis. In addition, analysis of the gag sequence phylogeny in one family demonstrated that CTL escape variants can be successfully transmitted both horizontally and vertically. To test the hypothesis further, a larger cohort of transmitting mothers (n=8) and non-transmitters (n=14) were studied. Variation within the SL9 epitope was associated with expression of HLA-A2 (P=0.04) but overall no clear link between variation from the SL9 consensus sequence and MTCT was established. However, the high level of background diversity within p17 Gag served to obscure any possible association between escape and MTCT. In conclusion, these studies highlighted the obstacles to demonstrating CTL escape arising at this particular epitope. Alternative strategies likely to be more definitive are discussed.

Effects of intrapartum zidovudine therapy on fetal heart rate parameters in women with human immunodeficiency virus infection

OBJECTIVE

To determine the effects of intrapartum maternal administration of zidovudine on fetal heart rate (FHR) parameters in women infected with the human immunodeficiency virus (HIV).

METHODS

Term HIV-infected women who delivered at our institution (1995-1998) were identified by medical records coding. Sixty minutes of FHR tracing prior to zidovudine administration and 60 min of FHR tracing 2 h after initiation of therapy were reviewed by 3 perinatologists blinded to patient status. Data were compared with paired t tests; p < 0.05 was considered significant. Inter- and intra-observer FHR interpretation variation were calculated.

RESULTS

Ten patients met study criteria. Their demographic data included: Maternal age 26.5 +/- 6.5 years, gestational age 38.9 +/- 1.3 weeks, median parity 2 (range 0-3). Eighty percent were African American. There were no significant differences in FHR parameters after intravenous zidovudine therapy (pretreatment versus 2 h after treatment) with respect to FHR baseline (p = 0.2), FHR variability (p = 0.3), or the number of accelerations (p = 0.1). There was also no difference in the number of variable (moderate or severe), early, or prolonged decelerations following zidovudine infusion.

CONCLUSION

Two hours of continuous intrapartum intravenous infusion of zidovudine does not alter any parameter of the FHR in the laboring HIV-infected gravida.

Preventing perinatal transmission of HIV: an evidence-based update for midwives

This article presents an update on human immunodeficiency virus care in the United States, with an emphasis on care during pregnancy and strategies to prevent perinatal transmission. Common drug regimens are reviewed. Obstetric factors related to transmission, such as mode of delivery, also are discussed. Guidelines for collaboration between midwives and human immunodeficiency virus specialists are outlined.

Guidelines for the management of HIV infection in pregnant women and the prevention of mother-to-child transmission

AIMS OF THE GUIDELINES: These guidelines, drawn up by a multidisciplinary group of clinicians and lay workers active in the management of pregnant women infected with HIV, aim to give up-to-date information on interventions to reduce the risk of mother to child transmission of the virus. The evidence on the use of interventions to prevent mother to child transmission of HIV has been graded according to the strength of the data as per the definitions of the US Agency for Health Care Policy and Research [1]. Weighted evidence on the use of combination antiretroviral therapy (ART) for the treatment of HIV infection per se is presented in the BHIVA guidelines for adults [2,3]. The highest level evidence (i.e. randomised controlled trials (RCTs) or large, well conducted meta-analyses) is only available for formula feeding, prelabour caesarean section and zidovudine monotherapy. The need to treat mothers for HIV infection has led to the widespread use of ART in pregnancy which in turn results in new questions such as how to deliver when the mother, on therapy, has no detectable plasma viraemia with the most sensitive assays. In addressing many common and/or difficult clinical scenarios in the absence of 'best evidence' the guidelines rely heavily on 'expert opinion'. Recommendations for management are given in the section on clinical scenarios, and summarized in Table 3. An expanded version of these guidelines with an appendix on safety and toxicity data is available on the BHIVA website http://www.bhiva.org. The authors are available to discuss individual cases.

Predictors of intrauterine and intrapartum transmission of HIV-1 among Tanzanian women

OBJECTIVE

To examine predictors of vertical transmission of HIV-1 in Dar-es-Salaam, Tanzania.

DESIGN

Observational design.

METHODS

Consenting HIV-1-infected pregnant women (n = 1078) were enrolled in a trial to examine the role of vitamin supplements. Intrauterine HIV-1 infection (HIV-positive at birth); intrapartum and early breastfeeding transmission (HIV-positive at 6 weeks among those uninfected at birth) were defined using the PCR.

RESULTS

Of 734 infants who had a specimen taken at birth, 62 were HIV positive [8.4%; 95% confidence interval (CI),6.4--10.5%], whereas 59 infants were positive among 367 infants who were uninfected at birth and were retested at 6 weeks (16.1%; 95%CI, 12.3--19.8%). In multivariate analyses, maternal CD4 cell count, viral load, and clinical stage were significant predictors of both definitions of transmission. Viral load of 50 000 copies/ml or more at delivery was associated with a 4.21-fold increase in risk of intrapartum and early breastfeeding transmission (95%CI, 1.59--11.13;P = 0.004). Babies who were HIV negative at birth and born before 34 weeks of gestation were 2.19 times more likely to become infected during intrapartum and early breastfeeding periods compared with those born after 37 weeks (95%CI, 1.19--4.04; P = 0.01). Gonorrhea at baseline was related to intrauterine transmission [multivariate risk ratio (RR), 5.50; 95%CI, 2.04--14.81; P < 0.001] but not intrapartum and early breastfeeding transmission. Signs of lower genital infections at or after enrollment were also associated with transmission.

CONCLUSIONS

Reducing prematurity, rate of HIV disease progression, and maternal viral load at or after delivery could help to reduce vertical transmission. Treatment of sexually transmitted infections at onset of prenatal care, about 20 weeks on average, was inadequate for prevention of transmission. Whether sustained clearance of lower genital tract infections result in reduced transmission remains to be determined.

Use of interventions for reducing mother-to-child transmission of HIV in Australia

OBJECTIVE

To describe the extent and outcome of use of interventions for reducing the risk of HIV transmission from mother to child in Australia.

DESIGN

National surveillance for perinatal exposure to HIV.

PARTICIPANTS AND SETTING

Notified cases of HIV infection in women in Australia and their perinatally exposed children, 1982-1999.

OUTCOME MEASURES

Trends over time in use of interventions (antiretroviral therapy in pregnancy, elective caesarean delivery and avoidance of breastfeeding) and perinatally acquired HIV infection.

RESULTS

By 31 March 2000, 204 children were reported as having been born in 1982-1999 to 162 women whose HIV infection had been diagnosed by 31 December 1999. The child's HIV infection status was established for 182 (89.2%); the mother's HIV infection was diagnosed antenatally in 91 of these cases (50%). Among women diagnosed antenatally, use of elective caesarean delivery and antiretroviral therapy in pregnancy increased significantly, from 3% and 14% by women whose children were born in 1982-1993, to 21% (P=0.01) and 88% (P<0.001), respectively, by women whose children were born in 1994-1999. Most women (95%) diagnosed antenatally avoided breastfeeding their children. The percentage of infected children born to women diagnosed antenatally declined from 26% among children born in 1982-1993 to 19% among those born in 1994-1999. The percentage of infected children was significantly lower among those whose mothers used antiretroviral therapy in pregnancy (11% versus 36%; P=0.03).

CONCLUSION

Antiretroviral use in pregnancy, elective caesarean delivery and avoidance of breastfeeding have been effective interventions for reducing the risk of mother-to-child HIV transmission in Australia. While the rate of perinatal HIV transmission has declined, it remains high in comparison with rates reported from other industrialised countries.

Preventing vertical HIV transmission in the year 2000: progress and prospects--a review

In the USA, progress in the ability to eliminate vertical HIV-1 transmission that was unthinkable just a few years ago has been virtually achieved with fewer than 200 new cases of infant HIV infection reported in 1999. Nevertheless, critical research questions as well as public health challenges remain. New infant HIV infections continue to occur among women who did not obtain prenatal care or who were not offered HIV testing during pregnancy and innovative approaches are needed to address these barriers. The CDC-funded Mother-Infant Rapid Intervention At Delivery (MIRIAD) Study in five US metropolitan areas is one such approach that will test the feasibility of offering rapid testing to women presenting late in pregnancy or at delivery with undocumented HIV status. In addition, further research addressing the role of the placenta in preventing or enhancing in utero HIV transmission is needed. Internationally, new clinical trial findings provide hope that a short course of antiretrovirals can substantially reduce vertical HIV-1 transmission in resource-poor settings in the developing world where most paediatric HIV infections occur. Future research will focus on the role of post-perinatal exposure prophylaxis with antiretrovirals administered to the infant and on the prevention of postnatal transmission of HIV-1 through breast milk while maintaining adequate nutrition. A major challenge is to translate trial results into a coordinated public health implementation plan in order to maximally reduce mother-to-child HIV-1 transmission worldwide.

[Management of pregnant women infected with HIV at Bichat Hospital between 1990 and 1998: analysis of 202 pregnancies]

OBJECTIVE

To describe medical and obstetrical prenatal care of pregnant women infected by HIV-1 emphasizing the role of cesarean section.

DESIGN

A retrospective study of 202 pregnancies followed between 1990 and 1998 in a french hospital in Paris.

RESULTS

56.9% of the women were born in subsaharian Africa; 80.2% were infected by sexual intercourse and the seropositivity was discovered during the pregnancy in 51% of the cases. Viral coinfections by hepatitis B virus, hepatitis C virus and Human papillomavirus were found respectively in 14.7%, 16.5% and 13% of the pregnancies. Prematurity occurred in 15% of the deliveries. Efficacy of antiretroviral therapy was confirmed in this study: 5.7% of the children were infected despite the antiretrovial treatment versus 19.3% without treatment (p < 0.03). Prophylactic cesarean section was proposed to the patients since 1994; the morbidity of cesarean was 8.8% (69 cesarean sections).

CONCLUSION

The policy of the association of prophylactic cesarean section and monotherapy by Zidovudine is validated by recent studies. The extension of prophylatic cesarean section to all the pregnant women infected by HIV is proposed. However the evaluation of the morbidity of the cesarean section in HIV infected women needs a prospective case-control study.

Perinatal transmission of major, minor, and multiple maternal human immunodeficiency virus type 1 variants in utero and intrapartum

Previous studies have provided conflicting data on the presence of selective pressures in the transmission of a homogeneous maternal viral subpopulation to the infant. Therefore, the purpose of this study was to definitively characterize the human immunodeficiency virus type 1 (HIV-1) quasispecies transmitted in utero and intrapartum. HIV-1 envelope gene diversity from peripheral blood mononuclear cells and plasma was measured during gestation and at delivery in mothers who did and did not transmit HIV perinatally by using a DNA heteroduplex mobility assay. Children were defined as infected in utero or intrapartum based on the timing of the first detection of HIV. Untreated transmitting mothers (n = 19) had significantly lower HIV-1 quasispecies diversity at delivery than untreated nontransmittting mothers (n = 18) (median Shannon entropy, 0.711 [0.642 to 0.816] versus 0.853 [0.762 to 0.925], P = 0.005). Eight mothers transmitted a single major env variant to their infants in utero, and one mother transmitted a single major env variant intrapartum. Four mothers transmitted multiple HIV-1 env variants to their infants in utero, and two mothers transmitted multiple env variants intrapartum. The remaining six intrapartum- and two in utero-infected infants had a homogeneous HIV-1 env quasispecies which did not comigrate with their mothers' bands at their first positive time point. In conclusion, in utero transmitters were more likely to transmit single or multiple major maternal viral variants. In contrast, intrapartum transmitters were more likely to transmit minor HIV-1 variants. These data indicate that different selective pressures, depending on the timing of transmission, may be involved in determining the pattern of maternal HIV-1 variant transmission.

Duration of ruptured membranes and vertical transmission of HIV-1: a meta-analysis from 15 prospective cohort studies

OBJECTIVE

To test the a priori hypothesis that longer duration of ruptured membranes is associated with increased risk of vertical transmission of HIV.

DESIGN

The relationship between duration of ruptured membranes and vertical transmission of HIV was evaluated in an individual patient data meta-analysis.

METHODS

Eligible studies were prospective cohort studies including at least 100 mother-child pairs, from regions where HIV-infected women are counselled not to breastfeed. Analyses were restricted to vaginal deliveries and non-elective Cesarean sections; elective Cesarean section deliveries (those performed before onset of labour and before rupture of membranes) were excluded.

RESULTS

The primary analysis included 4721 deliveries with duration of ruptured membranes < or = 24 h. After adjusting for other factors known to be associated with vertical transmission using logistic regression analysis to assess the strength of the relationship, the risk of vertical HIV transmission increased approximately 2% with an increase of 1 h in the duration of ruptured membranes [adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.04; for each 1 h increment]. There were no significant interactions of duration of ruptured membranes with study cohort or with any of the covariates, except maternal AIDS. Among women diagnosed with AIDS, the estimated probability of transmission increased from 8% to 31% with duration of ruptured membranes of 2 h and 24 h respectively (P < 0.01).

CONCLUSIONS

These results support the importance of duration of ruptured membranes as a risk factor for vertical transmission of HIV and suggest that a diagnosis of AIDS in the mother at the time of delivery may potentiate the effect of duration of ruptured membranes.

Vaginal lavage with chlorhexidine during labour to reduce mother-to-child HIV transmission: clinical trial in Mombasa, Kenya

OBJECTIVES

To evaluate the effect of vaginal lavage with diluted chlorhexidine on mother-to child transmission of HIV (MTCT) in a breastfeeding population.

METHODS

This prospective clinical trial was conducted in a governmental hospital in Mombasa, Kenya. On alternating weeks, women were allocated to non-intervention or to intervention consisting of vaginal lavage with 120 ml 0.2% chlorhexidine, later increased to 0.4%, repeated every 3 h from admission to delivery. Infants were tested for HIV by DNA polymerase chain reaction within 48 h and at 6 and 14 weeks of life.

RESULTS

Enrolment and follow-up data were available for 297 and 309 HIV-positive women, respectively, in the non-lavage and the lavage groups. There was no evidence of a difference in intrapartum MTCT (17.2 versus 15.9%, OR 0.9, 95% CI 0.6-1.4) between the groups. Lavage solely before rupture of the membranes tended towards lower MTCT with chlorhexidine 0.2% (OR 0.6, 95% CI 0.3-1.1), and even more with chlorhexidine 0.4% (OR 0.1, 95% CI 0.0-0.9).

CONCLUSION

The need remains for interventions reducing MTCT without HIV testing, often unavailable in countries with a high prevalence of HIV. Vaginal lavage with diluted chlorhexidine during delivery did not show a global effect on MTCT in our study. However, the data suggest that lavage before the membranes are ruptured might be associated with a reduction of MTCT, especially with higher concentrations of chlorhexidine.

Mother-to-child transmission of drug-resistant HIV

Mother-to-child transmission of HIV-I is responsible for the infection of hundreds of thousands of infants every year. The use of prophylactic antiretroviral treatments has brought about a dramatic decrease in the risk of transmission. Nevertheless, vertical transmission can still occur. In some cases, the presence of drug-resistant HIV-I strains in the mother has been responsible for the failure of the prophylactic scheme. Moreover, these strains have also been detected in the newborn. The aim of this review is to provide updated information on mother-to-child transmission of drug-resistant HIV strains and to help guide treatment decisions during pregnancy.

Multicenter review of protease inhibitors in 89 pregnancies

CONTEXT

Despite the success of highly active antiretroviral therapy, the optimal approach for preventing perinatal HIV-1 transmission is not known.

OBJECTIVE

A retrospective survey was conducted at six centers in the United States and Puerto Rico from January 1997 to October 1998 to evaluate the effects of protease inhibitor use during pregnancy on maternal and infant safety, prematurity rate, and frequency of perinatal HIV-1 transmission.

RESULTS

In the study, 91 live infants, including 3 sets of twins, and 1 neonate who died shortly after birth were born to 89 women. HIV perinatal transmission rate in this series was 0 (95% confidence interval [CI], 0%-3%). Prematurity rate was 19.1%, comparable to rates in earlier reports of HIV-1-infected women. In multiple regression analysis, only cocaine use and premature rupture of membranes were associated with prematurity (p =.03 and.008, respectively). The gestational week during which the protease inhibitors were initiated was not found to be significantly associated with prematurity. Adverse maternal, obstetric, and infant events possibly related to protease inhibitors were uncommon.

CONCLUSIONS

Protease inhibitors appeared generally safe in mothers and infants in this series. No perinatal HIV-1 transmission occurred. Further prospective, controlled studies are needed to define the optimal management of HIV-1 in pregnancy.

The cost-effectiveness of elective Cesarean delivery for HIV-infected women with detectable HIV RNA during pregnancy

OBJECTIVES

To determine the net health consequences, costs, and cost-effectiveness of alternative delivery strategies for HIV-infected pregnant women with detectable HIV RNA in the USA.

DESIGN

Cost-effectiveness analysis using a probabilistic decision model.

METHODS

The model compared two strategies: elective Cesarean section and vaginal delivery. Data for HIV transmission rate, maternal death rate, health-related quality of life and costs were obtained from the literature, national databases, and a tertiary hospital's cost accounting system. Model outcomes included total lifetime costs, quality-adjusted life expectancy, maternal death rate, HIV transmission rate, and incremental cost-effectiveness ratios.

RESULTS

Elective Cesarean section resulted in a vertical HIV transmission rate of 34.9 per 1000 births compared with 62.3 per 1000 births for vaginal delivery. Elective Cesarean section was more effective (38.7 quality adjusted life years per mother and child pair) and less costly ($10600 per delivery) than trial of labor (38.2 combined quality adjusted life years at a cost of $14500 per delivery). However, elective Cesarean section increased maternal mortality by 2.4 deaths per 100000 deliveries. The results were consistent over a wide range of the variables, but were sensitive to the risk of HIV transmission with vaginal delivery and the relative risk of HIV transmission with elective Cesarean section.

CONCLUSIONS

In pregnant HIV-infected women with detectable HIV RNA, elective Cesarean section would reduce total costs and increase overall quality-adjusted life expectancy for the mother-child pair, albeit at a slight loss of quality adjusted life expectancy to the mother.

Infant birth weight among women with or at high risk for HIV infection: the impact of clinical, behavioral, psychosocial, and demographic factors

The purpose of these analyses was to provide a prospective examination of the impact of HIV on birth weight using clinical, behavioral, psychosocial, and demographic correlates. HIV-positive (n = 319) and HIV-negative (n = 220) pregnant women matched for HIV risk factors (i.e., drug use and sexual risk behaviors) were interviewed during the 3rd trimester of pregnancy and 6 weeks postpartum. Medical chart reviews were also conducted for the HIV-seropositive pregnant women to verify pregnancy-related and birth outcome data. In a logistic regression analysis, model chi2(9, N = 518) = 124.8, p < .001, controlling for parity and gestational age, women who were HIV seropositive were 2.6 times more likely to have an infant with low birth weight. In addition, Black women and those who did not live with their partners were more than 2 times as likely to have infants with low birth weight, and those who smoked were 3.2 times more likely to have infants with low birth weight. Knowing that women with HIV, those who are Black, and those not living with a partner are at highest risk for adverse birth outcomes can help those in prenatal clinics and HIV specialty clinics to target resources and develop prevention interventions. This is particularly important for women with HIV because birth weight is associated with risk of HIV transmission from mother to child.

Exposure to HIV-1 during delivery and mother-to-child transmission

BACKGROUND

The correlation between the presence of HIV-1 in maternal cervicovaginal secretions and in the infant's oro-pharyngal secretions at birth, and mother-to-child HIV transmission (MTCT) were examined to obtain a better understanding of its mechanism.

METHODS

Women without medical and obstetrical complications, living within a reasonable distance of the government hospital in Mombasa, Kenya, were recruited after informed consent. Maternal and infant characteristics were collected. Polymerase chain reaction was used to detect HIV-1 in cervico-vaginal and oro-pharyngal secretions. Infants were tested for HIV-1 by polymerase chain reaction within 48 h and at 6 weeks after delivery.

RESULTS

Between April 1998 and April 1999, 228 woman-infant pairs were included in the study. HIV-1 DNA in cervico-vaginal secretions was independently associated with HIV-1 maternal viral load and with infant birth-weight, whereas HIV-1 RNA was associated with maternal viral load and maternal age. HIV-1 DNA in the oropharyngal secretions was also independently associated with maternal viral load. MTCT rate at the age of 6 weeks was 23.6%. Intrapartum and early postpartum HIV transmission was independently associated with maternal viral load [adjusted odds ratio (OR), 1.6; 95% confidence interval (CI),1.0-2.7], detection of HIV-1 RNA in cervico-vaginal secretions (adjusted OR, 3.2; 95% CI, 1.5-7.3) and of HIV-1 DNA in oro-pharyngeal secretions (adjusted OR, 3.2; 95% CI, 1.1-9.0).

DISCUSSION

As far as is known, this is the first study showing that infant exposure to HIV-1 in the birth canal and the presence of HIV-infected cells in the infant's oropharyngeal cavity are independently associated with intrapartum and early postpartum MTCT. It supports the hypothesis that MTCT could occur through the oral route.

Management of HIV infection during pregnancy

Optimal management of HIV infection in pregnancy requires maternal use of potent antiretroviral therapy to prevent disease progression in the mother and vertical transmission to the newborn. Combination antiretroviral therapy substantially reduces the risk of perinatal HIV transmission and appears to be more effective than zidovudine monotherapy. The administration of single dose nevirapine to mother intrapartum and infant postpartum effectively reduces vertical HIV transmission and is less costly and cumbersome than zidovudine regimens. Elective cesarean section reduces vertical transmission of HIV but its benefit is less clear when antiretroviral therapy decreases maternal plasma HIV viral load to low levels at delivery. If possible, HIV-infected mothers should avoid breastfeeding. The present review discusses the importance of early identification of maternal HIV infection, strict adherence to combination antiretroviral regimens to prevent drug resistance, developing a better understanding of antiretroviral pharmacokinetics in pregnancy and short/long term safety of anti-HIV drugs.

Absence of maternal-fetal transmission of human immunodeficiency virus type 1 to second-trimester fetuses

OBJECTIVE

The aim of this study was to evaluate the contribution of in utero infection to the vertical transmission of human immunodeficiency virus type 1 during the second trimester.

STUDY DESIGN

We examined fetal tissues from 21 second-trimester prostaglandin-induced abortions among human immunodeficiency virus type 1-infected women and compared the fetal vertical transmission rates with those among children born to human immunodeficiency virus-seropositive women. The presence of human immunodeficiency virus type 1 nucleic acid sequences was investigated with two different highly sensitive polymerase chain reaction techniques in tissue samples from the fetal thymus, lung, and brain.

RESULTS

No human immunodeficiency virus type 1 deoxyribonucleic acid was detected in any of the samples.

CONCLUSION

The absence of human immunodeficiency virus type 1 in all fetuses in our study is compatible with a low rate of maternal-fetal transmission during the second trimester of pregnancy.

The changing HIV epidemic in Italian pregnant women

OBJECTIVE

To describe changes in the characteristics of HIV-pregnant women in Italy and the impact of strategies for prevention of HIV vertical transmission.

STUDY DESIGN

Since 1985, HIV-infected women and their children are followed in 23 European centres in the European Collaborative Study (ECS), according to a standard protocol. Eight Italian Obstetric units participating in the ECS enrolled 815 patients.

RESULTS

Overall use of zidovudine to reduce HIV vertical transmission has increased significantly since 1994 and between 1995 and 1997, 57% of Italian women were treated. However, 27% of babies received the infant component of the 076 regimen. Over the years, age at delivery has increased and their CD4 count at delivery decreased, most likely reflecting heterosexually infected women with a longer duration of infection. The increasing rate of elective caesarean section (42%) is not related to maternal, foetal or obstetrical indications, but its use as an intervention to reduce HIV vertical transmission.

CONCLUSIONS

The identification of HIV-infected women during pregnancy or before delivery ensures the appropriate management of the woman and her child, and clinicians should be aware of the increasing number of women with heterosexual acquisition of HIV-infection who may be less easily identified.

Risk factors for preterm birth, low birth weight, and intrauterine growth retardation in infants born to HIV-infected pregnant women receiving zidovudine. Pediatric AIDS Clinical Trials Group 185 Team

OBJECTIVE

To evaluate independent contributions of maternal factors to adverse pregnancy outcomes (APO) in HIV-infected women receiving antiretroviral therapy (ART).

DESIGN

Risk factors for preterm birth (< 37 weeks gestation), low birth weight (LBW) (< 2500 g), and intrauterine growth retardation (IUGR) (birth weight < 10th percentile for gestational age) examined in 497 HIV-infected pregnant women enrolled in PACTG 185, a perinatal clinical trial.

METHODS

HIV RNA copy number, culture titer, and CD4 lymphocyte counts were measured during pregnancy. Information collected included antenatal use of cigarettes, alcohol, illicit drugs; ART; obstetric history and complications.

RESULTS

Eighty-six percent were minority race/ethnicity; 86% received antenatal monotherapy, predominantly zidovudine (ZDV), and 14% received combination antiretrovirals. Preterm birth occurred in 17%, LBW in 13%, IUGR in 6%. Risk of preterm birth was independently associated with prior preterm birth [odds ratio (OR) 3.34; P < 0.001], multiple gestation (OR, 6.02; P = 0.011), antenatal alcohol use (OR, 1.91; P = 0.038), and antenatal diagnosis of genital herpes (OR, 0.24; P = 0.022) or pre-eclampsia (OR, 6.36; P = 0.025). LBW was associated with antenatal diagnosis of genital herpes (OR, 0.08; P = 0.014) and pre-eclampsia (OR, 5.25; P = 0.049), and baseline HIV culture titer (OR, 1.41; P = 0.037). IUGR was associated with multiple gestation (OR, 8.20; P = 0.010), antenatal cigarette use (OR, 3.60; P = 0.008), and pre-eclampsia (OR, 12.90; P = 0.007). Maternal immune status and HIV RNA copy number were not associated with APO.

CONCLUSIONS

Risk factors for APO in antiretroviral treated HIV-infected women are similar to those reported for uninfected women. These data suggest that provision of prenatal care and ART may reduce APO.

Mother-to-infant transmission of GB virus type C/HGV

BACKGROUND

The potentially hepatotropic flavivirus-like virus, GB virus type C (GBV-C)/HGV, has been detected in a few patients with acute and chronic hepatitis and in a certain proportion of blood donors and recipients of blood or blood components.

STUDY DESIGN AND METHODS

Sera from 2979 pregnant Japanese women were examined for the presence of GBV-C/HGV RNA by nested RT-PCR. Mothers who were positive for viral RNA and their 34 infants were followed and tested for infection.

RESULTS

Of the 2979 women, 32 (1.1%) were positive for GBV-C/HGV RNA. Twenty-six (76.5%) of 34 babies born to these women were positive for the virus when first tested. A significantly higher titer of viral RNA was observed in mothers whose infants were infected than in those whose infants were uninfected (mean +/- SD, 10(6.3 +/- 0.9) vs. 10(4.6 +/- 0.9)/mL; p<0.001). Twenty-three (96%) of 24 babies born to mothers whose serum viral titers were 10(6) mL or more were infected with the virus. Infants delivered by elective caesarean section had a lower risk (OR, 0.13; 95% CI, 0.02-0.82) than those delivered vaginally or by emergency caesarean section. No other risk factors for mother-to-infant transmission were confirmed.

CONCLUSIONS

GBV-C/HGV is frequently transmitted from mothers to infants in the general population. The most critical factor is the titer of viral RNA in the maternal serum. By the use of elective caesarean section in women with high titers of viral RNA, vertical transmission of the virus may be lessened.

Epidemiology of HIV infection in the newborn

Vertical transmission of HIV infection can take place in utero, during delivery and postnatally through breastfeeding, with about three-quarters of infections occurring around the time of delivery in non-breastfeeding populations. In Europe, in the absence of specific interventions, the vertical transmission rate was 15-20%. High maternal load is the major risk factor for both intra-uterine and intra-partum mother-to-child transmission. Prematurity is the most common adverse neonatal outcome associated with maternal HIV infection. Earlier diagnosis of paediatric HIV infection than previously available is now possible with virological tests, particularly HIV DNA polymerase chain reaction. An estimated one fifth of infected children will have been diagnosed with AIDS or have died by 12 months of age, rising to a third by 6 years of age. Surgical and therapeutic interventions are effective in reducing vertical transmission risk, in addition to the avoidance of breastfeeding. Caesarean section delivery before labour and before rupture of membranes approximately halves the risk of transmission, while prophylactic zidovudine therapy according to the ACTG076 regimen reduces transmission by up to two-thirds, transmission is reduced even further with both interventions. Trials of short-course zidovudine regimens show their effectiveness in reducing vertical transmission, in breastfeeding and non-breastfeeding populations. Nevirapine has been shown to be significantly more effective than short course zidovudine regimens in breastfeeding populations, but is still under evaluation in non-breastfeeding populations additionally receiving routine anti-retroviral prophylaxis. Reports of a small number of serious adverse events in uninfected children exposed in utero or neonatally to antiretroviral therapy need further investigation. Trials of vitamin A supplementation to reduce vertical transmission have had negative results, while the effectiveness of vaginal lavage and passive immune therapy in reducing vertical transmission remains uncertain.

[Reduction of vertical HIV transmission: a challenge for nursing care]

With the crescent rates of HIV infection within female population in reproductive age, we may observe a correspondent increase in congenital infections. Thus, the obstetric nurse must be updated to participate and to develop programs of pre-natal care for HIV pregnant women. The purpose of this study was to review the pre-natal follow-up of this population regarding nursing care. Authors did not intend to approach all aspects of this subject, especially considering that investigations extend the great improvements already achieved since the acknowledge of the disease.

An overview of HIV infection and AIDS: etiology, pathogenesis, diagnosis, epidemiology, and occupational exposure

Thanks to a worldwide collaborative effort among health care providers, academia, governments, and industry, our knowledge base about infection caused by the human immunodeficiency virus (HIV) has expanded exponentially. During the past 2 decades, we have learned about its pathogenesis, virology, immunology, epidemiology and treatment. In the developed world, the approach to persons with HIV disease has evolved from palliative disease care to use of a chronic disease model, where survival is measured by decades, not months or years. More and more, clinical decision-making for HIV-infected patients is driven by comorbidities, including cardiothoracic disease. Thus, our clinically stable HIV population is increasingly accessing those health care services required by any maturing population, including the usual services of cardiothoracic surgeons. In this article, we review the basic facts of HIV disease, with an emphasis on occupational risks and infection control procedures.

[Estimate of HIV-1 infection prevalence in pregnant women and effectiveness of zidovudine administered during pregnancy in the prevention of vertical transmission]

BACKGROUND

Despite the proven efficacy of zidovudine (ZDV) for reducing perinatal transmission of HIV-1, questions remain about its implementation and effectiveness in routine practice. The aims of this study were to assess the impact of ZDV administered during pregnancy in preventing perinatal HIV-1 transmission, and to determine the proportion of early identification of maternal HIV-1 infection over time.

PATIENTS AND METHODS

We prospectively followed from birth a cohort of children born between 1/1/1987 and 31/10/1997 to HIV-1-infected mothers. Infant infection status was assessed by follow-up beyond 18 months or HIV-PCR up to 3 months of age.

RESULTS

229 mothers and 248 infants were identified in the cohort. ZDV was administered during pregnancy as monotherapy to 34 mothers for a mean of 4.7 (3.1) months prior to delivery. There were no differences in baseline characteristics between the treated and untreated groups. Mean (SD) CD4 cell count was 465 (261) cells x 10(6)/l. Factors associated with transmission were a more prolonged time of rupture of obstetric membranes (median 6 vs 1.04 hours; p = 0.023) and ZDV treatment. Among the ZDV-treated mothers only one child was infected (2.9%), whereas 37 children born to 212 untreated women became infected. (OR: 0.14; 95% CI: 0.07-0.92). The estimated prevalence of HIV-1 in pregnant women in our area is about 0.39% (95% CI: 0.34-0.45). From 1987 to 1991, 9.7% of infected women were nor identified at the perinatal period, as compared to 2.5% in the last 5 years of the study period (p = 0.034).

CONCLUSIONS

In this study, the estimated prevalence of HIV-1 infection is high. ZDV during pregnancy is significantly associated with a decrease in perinatal transmission in our setting. The awareness of an effective treatment might have contributed to the increased identification of HIV-infected mothers prior to delivery observed over time in our cohort of children born to HIV-infected mothers.

Common antiviral agents used in women's and children's care, part 2

Antiviral agents that act in the later phases of the viral reproductive cycle are used primarily against human immunodeficiency virus (HIV). Combination therapy for HIV with drugs from different categories is more effective than monodrug therapy in slowing disease progression and improving survival. Antiviral treatment for all pregnant women with HIV is recommended for prevention of vertical transmission. Procedures are discussed for postexposure prophylaxis for health care providers exposed to HIV.