The effect of maternal viral load on the risk of perinatal transmission of HIV-1. New York City Perinatal HIV Transmission Collaborative Study Group

Prevalence and risk factors of detectable HIV viral load among pregnant women with HIV infection seeking antenatal care in Southern Malawi

We evaluated detectable viral load (VL) in pregnant women established on antiretroviral therapy (ART) for at least 6 months before conception and those self-reported as ART naïve at first antenatal care (ANC) at two government clinics in Southern Malawi. We used logistic regression to identify the predictors of detectable viral load (VL), defined as any measure greater than 400 copies/ml. Of 816 women, 67.9% were established on ART and 32.1% self-reported as ART naïve. Among women established on ART, 10.8% had detectable VL and 9.9% had VL >1000 copies/ml (WHO criteria for virological failure). In adjusted analysis, among women established on ART, virological failure was associated with younger age (p = .02), "being single/widowed" (p = 0.001) and no previous deliveries (p = .05). One fifth of women who reported to be ART-naive were found to have an undetectable VL at first ANC. None of the demographic factors could significantly differentiate those with high versus low VL in the ART-naïve sub-sample. In this cohort, approximately 90% of women who had initiated ART prior to conception had an undetectable VL at first ANC. This demonstrates good success of the ART program but identifies high risk populations that require additional support.

Assessment of minority frequency pretreatment HIV drug-resistant variants in pregnant women and associations with virologic non-suppression at term

Objective

To assess in ART-naïve pregnant women randomized to efavirenz- versus raltegravir-based ART (IMPAACT P1081) whether pretreatment drug resistance (PDR) with minority frequency variants (<20% of individual’s viral quasispecies) affects antiretroviral treatment (ART)-suppression at term.

Design

A case-control study design compared PDR minority variants in cases with virologic non-suppression (plasma HIV RNA >200 copies/mL) at delivery to randomly selected ART-suppressed controls.

Methods

HIV pol genotypes were derived from pretreatment plasma specimens by Illumina sequencing. Resistance mutations were assessed using the HIV Stanford Database, and the proportion of cases versus controls with PDR to their ART regimens was compared.

Results

PDR was observed in 7 participants (11.3%; 95% CI 4.7, 21.9) and did not differ between 21 cases and 41 controls (4.8% vs 14.6%, p = 0.4061). PDR detected only as minority variants was less common (3.2%; 95% CI 0.2, 11.7) and also did not differ between groups (0% vs. 4.9%; p = 0.5447). Cases’ median plasma HIV RNA at delivery was 347c/mL, with most (n = 19/22) showing progressive diminution of viral load but not ≤200c/mL. Among cases with viral rebound (n = 3/22), none had PDR detected. Virologic non-suppression at term was associated with higher plasma HIV RNA at study entry (p<0.0001), a shorter duration of ART prior to delivery (p<0.0001), and randomization to efavirenz- (versus raltegravir-) based ART (p = 0.0085).

Conclusions

We observed a moderate frequency of PDR that did not significantly contribute to virologic non-suppression at term. Rather, higher pretreatment plasma HIV RNA, randomization to efavirenz-based ART, and shorter duration of ART were associated with non-suppression. These findings support early prenatal care engagement of pregnant women and initiation of integrase inhibitor-based ART due to its association with more rapid suppression of plasma RNA levels. Furthermore, because minority variants appeared infrequent in ART-naïve pregnant women and inconsequential to ART-suppression, testing for minority variants may be unwarranted.

Prevention and Initial Management of HIV Infection

Since July 2017, when In the Clinic last addressed management of HIV infection, there have been meaningful improvements in our ability to prevent HIV and to manage patients living with HIV. New approaches to preexposure prophylaxis and more effective treatments have made the elimination of HIV infection a feasible goal. The federal "Ending the HIV Epidemic" initiative aims at a 90% reduction in new HIV diagnoses by 2030. This article provides updated information on how clinicians should use these improvements to manage their patients who are at risk for HIV infection or are newly diagnosed with HIV.

Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure

Despite the significant progress that has been made to eliminate vertical HIV infection, more than 150,000 children were infected with HIV in 2019, emphasizing the continued need for sustainable HIV treatment strategies and ideally a cure for children. Mother-to-child-transmission (MTCT) remains the most important route of pediatric HIV acquisition and, in absence of prevention measures, transmission rates range from 15% to 45% via three distinct routes: in utero, intrapartum, and in the postnatal period through breastfeeding. The exact mechanisms and biological basis of these different routes of transmission are not yet fully understood. Some infants escape infection despite significant virus exposure, while others do not, suggesting possible maternal or fetal immune protective factors including the presence of HIV-specific antibodies. Here we summarize the unique aspects of HIV MTCT including the immunopathogenesis of the different routes of transmission, and how transmission in the antenatal or postnatal periods may affect early life immune responses and HIV persistence. A more refined understanding of the complex interaction between viral, maternal, and fetal/infant factors may enhance the pursuit of strategies to achieve an HIV cure for pediatric populations.

The geographic distribution of priority population groups for the elimination of mother-to-child transmission of HIV in South Africa

Background

Women of reproductive age living with HIV (WRLHIV), HIV-positive pregnant women, adolescent girls and young women (AGYW) are key populations for eliminating mother-to-child of HIV (eMTCT) in South Africa. We describe the geographical distribution of WRLHIV, their pregnant counterparts and AGYW for risk-adjusted allocation of eMTCT interventions.

Methods

For the year 2018, we triangulated data from the Thembisa Model with five routine HIV-related and demographic data sources to determine the distribution of WRLHIV (15–49 years) and AGYW (15–24 years) nationally and by province. Data analysed included total population estimates, number of live-births, live-births to HIV-positive women, age-specific HIV prevalence rates, intrauterine (IU)-transmission rates and IU-case rates/100 000 live-births. IU-transmission rates and IU-case rates were calculated from de-duplicated routine HIV test-data for neonates (aged <7days). Data de-duplication was achieved by a patient-linking algorithm that uses probabilistic matching of demographics (name, surname, date of birth), supplemented by manual matching to account for spelling errors.

Results

There were 58 million people in South Africa in 2018. Females (all ages) constituted 51% of the population. Women of reproductive age constituted 27% and AGYW constituted 8% of the total population. WRLHIV, AGYW living with HIV and HIV-positive pregnant women accounted for 7%, 0.8% and 0.4% of the total population respectively. Gauteng was the most populous province followed by KwaZulu-Natal, with Western Cape and Eastern Cape in third and fourth positions. The distribution of WRLHIV and AGYW followed a similar trend. However, Mpumalanga and Limpopo provinces had higher proportions of WRLHIV and AGYW living with HIV ahead of Western Cape. KwaZulu-Natal had the highest number of live-births to HIV-positive women. The national IU-transmission rate of <1% translated into 241 cases/100 000. While provincial IU-case rates were fairly similar at 179–325, districts IU-case rates varied, ranging from 87–415 cases/100 000 live-births.

Conclusion

Findings suggest that the need for eMTCT interventions is greatest in Gauteng, KwaZulu-Natal, Western Cape and Eastern Cape. Limpopo and Mpumalanga provinces may require more HIV prevention and family planning services because of high fertility rates, high number of WRLHIV and AGYW living with HIV. eMTCT will require robust viral load monitoring among WRLHIV, pregnant and breastfeeding women. The national laboratory database can provide this service near-real time.

Reproductive and sexual health knowledge, experiences, and milestones in young adults with life-long HIV

Reproductive and sexual health outcomes of adults with perinatal human immunodeficiency virus (PHIV) have not been well-characterized. This prospective cross-sectional study of 35 adult persons living with HIV (PLWH) from early life and 20 matched HIV-negative controls assessed quality of life, depressive symptoms, HIV transmission knowledge, and sexual/reproductive behaviors through self-report questionnaires. PLWH scored significantly worse than controls on depressive symptoms (p = 0.04) and two of six quality of life domains (p = 0.03, p = 0.0002). In contrast, PLWH scored significantly higher on transmission knowledge in the context of family planning (p = 0.002). PLWH were more likely to learn about sex from healthcare providers (p = 0.002) and were more confident in their sexual/reproductive health knowledge (p < 0.05). Both groups reported inconsistent condom use, but PLWH were more likely to have planned pregnancies (p = 0.005) and to share pregnancy planning with their partners (p < 0.05). Despite the challenges of living with a chronic stigmatized condition, adults with PHIV were knowledgeable about HIV transmission and family planning and demonstrated sexual practices and reproductive outcomes similar to age-matched controls. However, sub-optimal rates of viral suppression, inconsistent condom use, and the psychosocial impact of living with HIV continue to require the attention of healthcare provides for young adults with PHIV.

Analysis of the TCR Repertoire in HIV-Exposed but Uninfected Infants

Maternal human immunodeficiency virus (HIV) infection has been shown to leave profound and lasting impacts on the HIV-exposed uninfected (HEU) infant, including increased mortality and morbidity, immunological changes, and developmental delays compared to their HIV-unexposed (HU) counterparts. Exposure to HIV or antiretroviral therapy may influence immune development, which could increase morbidity and mortality. However, a direct link between the increased mortality and morbidity and the infant's immune system has not been identified. To provide a global picture of the neonatal T cell repertoire in HEU versus HU infants, the diversity of the T cell receptor beta chain (TRB) expressed in cord blood samples from HEU infants was determined using next-generation sequencing and compared to healthy (HU) infants collected from the same community. While the TRB repertoire of HU infants was broadly diverse, in line with the expected idea of a naïve T cell repertoire, samples of HEU infants showed a significantly reduced TRB diversity. This study is the first to demonstrate differences in TRB diversity between HEU and HU cord blood samples and provides evidence that maternal HIV, in the absence of transmission, influences the adaptive immune system of the unborn child.

Interventions to significantly improve service uptake and retention of HIV-positive pregnant women and HIV-exposed infants along the prevention of mother-to-child transmission continuum of care: systematic review

OBJECTIVES

Despite the success of Prevention of Mother-to-Child Transmission of HIV (PMTCT) programmes, low uptake of services and poor retention pose a formidable challenge to achieving the elimination of vertical HIV transmission in low- and middle-income countries. This systematic review summarises interventions that demonstrate statistically significant improvements in service uptake and retention of HIV-positive pregnant and breastfeeding women and their infants along the PMTCT cascade.

METHODS

Databases were systematically searched for peer-reviewed studies. Outcomes of interest included uptake of services, such as antiretroviral therapy (ART) such as initiation, early infant diagnostic testing, and retention of HIV-positive pregnant and breastfeeding women and their infants. Interventions that led to statistically significant outcomes were included and mapped to the PMTCT cascade. An eight-item assessment tool assessed study rigour.

PROSPERO ID

CRD42017063816.

RESULTS

Of 686 citations reviewed, 11 articles met inclusion criteria. Ten studies detailed maternal outcomes and seven studies detailed infant outcomes in PMTCT programmes. Interventions to increase access to antenatal care (ANC) and ART services (n = 4) and those using lay cadres (n = 3) were most common. Other interventions included quality improvement (n = 2), mHealth (n = 1), and counselling (n = 1). One study described interventions in an Option B+ programme. Limitations included lack of HIV testing and counselling and viral load monitoring outcomes, small sample size, geographical location, and non-randomized assignment and selection of participants.

CONCLUSIONS

Interventions including ANC/ART integration, family-centred approaches, and the use of lay healthcare providers are demonstrably effective in increasing service uptake and retention of HIV-positive mothers and their infants in PMTCT programmes. Future studies should include control groups and assess whether interventions developed in the context of earlier 'Options' are effective in improving outcomes in Option B+ programmes.

Viraemia before, during and after pregnancy in HIV-infected women on antiretroviral therapy in rural KwaZulu-Natal, South Africa, 2010-2015

OBJECTIVES

Pregnancy and post-partum viral load suppression is critical to prevent mother-to-child HIV transmission and ensure maternal health. We measured viraemia risk before, during and after pregnancy in HIV-infected women.

METHODS

Between 2010 and 2015, 1425 HIV-infected pregnant women on lifelong antiretroviral therapy (ART) for at least six months pre-pregnancy were enrolled in a cohort study in rural KwaZulu-Natal, South Africa. Odds ratios were estimated in multilevel logistic regression, with pregnancy period time-varying.

RESULTS

Over half of 1425 women received tenofovir-based regimens (n = 791). Median pre-pregnancy ART duration was 2.1 years. Of 988 women (69.3%) with pre-pregnancy viral loads, 82.0%, 6.8% and 11.2% had VL <50, 50-999 and ≥1000 copies/ml, respectively. During pregnancy and at six, 12 and 24 months, viral load was ≥1000 copies/ml in 15.2%, 15.7%, 17.8% and 16.6% respectively; viral load <50 was 76.9%, 77%, 75.5% and 75.8%, respectively. Adjusting for age, clinical and pregnancy factors, viraemia risk (viral load ≥50 copies/ml) was not significantly associated with pregnancy [adjusted OR (aOR) 1.31; 95% CI 0.90-1.92], six months (aOR 1.30; 95% CI 0.83-2.04), 12 months (aOR 0.96; 95% CI 0.58-1.58) and 24 months (aOR 1.40; 95% CI 0.89-2.22) post-partum. Adjusting for ART duration-pregnancy period interaction, viraemia risk was 1.8 during pregnancy and twofold higher post-partum.

CONCLUSIONS

While undetectable viral load before pregnancy through post-partum was common, the UNAIDS goal to suppress viraemia in 90% of women was not met. Women on preconception ART remain vulnerable to viraemia; additional support is required to prevent mother-to-child HIV transmission and maintain maternal health.

Management of Newly Diagnosed HIV Infection

No field in medicine has moved as swiftly as HIV/AIDS over the past 35 years. Because of the rapid turnover of key information, this In the Clinic focuses on essential principles of care for newly diagnosed adults with HIV-1 infection and how to prevent infection in persons at risk. To ensure continued usefulness, future directions in therapy and how to access updated information on a continuous basis are emphasized.

Critical Review: Review of the Efficacy, Safety, and Pharmacokinetics of Raltegravir in Pregnancy

Raltegravir was previously considered an alternative antiretroviral in pregnancy because of limited data, but recent pregnancy guidelines recommend raltegravir as a preferred integrase treatment option. Data from published articles and preliminary meeting reports between 2001 and July 2015 are reviewed. The literature includes a total of 278 maternal-infant pairs who received raltegravir during pregnancy. The standard raltegravir dose seems safe and effective in preventing mother-to-child transmission in late pregnancy presenters with unknown or unsuppressed viral load, or in multidrug resistance. Viral decay was rapid allowing most women to deliver at undetectable viral levels. Raltegravir was well tolerated, with the exception of a few cases of transient increases in maternal transaminases. No infant adverse effect was consistently reported. Existing data support the use of raltegravir in antiretroviral-naive and experienced pregnant women.

Maternal Binding and Neutralizing IgG Responses Targeting the C-Terminal Region of the V3 Loop Are Predictive of Reduced Peripartum HIV-1 Transmission Risk

The development of an effective maternal HIV-1 vaccine that could synergize with antiretroviral therapy (ART) to eliminate pediatric HIV-1 infection will require the characterization of maternal immune responses capable of blocking transmission of autologous HIV to the infant. We previously determined that maternal plasma antibody binding to linear epitopes within the variable loop 3 (V3) region of HIV envelope (Env) and neutralizing responses against easy-to-neutralize tier 1 viruses were associated with reduced risk of peripartum HIV infection in the historic U.S. Woman and Infant Transmission Study (WITS) cohort. Here, we defined the fine specificity and function of the potentially protective maternal V3-specific IgG antibodies associated with reduced peripartum HIV transmission risk in this cohort. The V3-specific IgG binding that predicted low risk of mother-to-child-transmission (MTCT) was dependent on the C-terminal flank of the V3 crown and particularly on amino acid position 317, a residue that has also been associated with breakthrough transmission in the RV144 vaccine trial. Remarkably, the fine specificity of potentially protective maternal plasma V3-specific tier 1 virus-neutralizing responses was dependent on the same region in the V3 loop. Our findings suggest that MTCT risk is associated with neutralizing maternal IgG that targets amino acid residues in the C-terminal region of the V3 loop crown, suggesting the importance of the region in immunogen design for maternal vaccines to prevent MTCT.IMPORTANCE Efforts to curb HIV-1 transmission in pediatric populations by antiretroviral therapy (ART) have been highly successful in both developed and developing countries. However, more than 150,000 infants continue to be infected each year, likely due to a combination of late maternal HIV diagnosis, lack of ART access or adherence, and drug-resistant viral strains. Defining the fine specificity of maternal humoral responses that partially protect against MTCT of HIV is required to inform the development of a maternal HIV vaccine that will enhance these responses during pregnancy. In this study, we identified amino acid residues targeted by potentially protective maternal V3-specific IgG binding and neutralizing responses, localizing the potentially protective response in the C-terminal region of the V3 loop crown. Our findings have important implications for the design of maternal vaccination strategies that could synergize with ART during pregnancy to achieve the elimination of pediatric HIV infections.

Prevention of perinatal transmission of zidovudine- and nevirapine-resistant HIV

PURPOSE

The use of a three-drug regimen for the prevention of perinatal transmission of zidovudine- and nevirapine-resistant HIV is described.

SUMMARY

A 17-year-old Hispanic woman infected with HIV arrived at our clinic for the management of her first pregnancy. The patient was in her second trimester of her pregnancy, had not previously been treated with antiretroviral therapy, and was only taking daily prenatal vitamins at the time of her first clinic visit. Her HIV RNA viral load was 240 copies/mL, and the virus was resistant to both zidovudine and nevirapine. Nelfinavir (compounded suspension), lamivudine, and zidovudine were prescribed for the mother, though she was generally nonadherent to therapy. Nelfinavir, lamivudine, and zidovudine were initiated for the newborn within eight hours of delivery. Six months later, the patient returned to the clinic in the first trimester of her second pregnancy. At this visit, her HIV RNA viral load was 120 copies/mL. After the birth of her second child, the infant received the same regimen received by her firstborn: zidovudine 4 mg/kg orally twice daily for six weeks, lamivudine 2 mg/kg orally twice daily for two weeks, and nelfinavir 55 mg/kg orally twice daily for two weeks. At four months of age, each infant was found to be HIV-negative.

CONCLUSION

A prophylactic regimen that included nelfinavir, lamivudine, and zidovudine was used to prevent perinatal transmission of HIV in two neonates. The regimen was well tolerated, and both infants were determined to be HIV-negative at four months of age.

HIV viraemia and mother-to-child transmission risk after antiretroviral therapy initiation in pregnancy in Cape Town, South Africa

OBJECTIVES

Maternal HIV viral load (VL) drives mother-to-child HIV transmission (MTCT) risk but there are few data from sub-Saharan Africa, where most MTCT occurs. We investigated VL changes during pregnancy and MTCT following antiretroviral therapy (ART) initiation in Cape Town, South Africa.

METHODS

We conducted a prospective study of HIV-infected women initiating ART within routine antenatal services in a primary care setting. VL measurements were taken before ART initiation and up to three more times within 7 days postpartum. Analyses examined VL changes over time, viral suppression (VS) at delivery, and early MTCT based on polymerase chain reaction (PCR) testing up to 8 weeks of age.

RESULTS

A total of 620 ART-eligible HIV-infected pregnant women initiated ART, with 2425 VL measurements by delivery (median gestation at initiation, 20 weeks; median pre-ART VL, 4.0 log₁₀ HIV-1 RNA copies/mL; median time on ART before delivery, 118 days). At delivery, 91% and 73% of women had VL ≤ 1000 and ≤ 50 copies/mL, respectively. VS was strongly predicted by time on therapy and pre-ART VL. The risk of early MTCT was strongly associated with delivery VL, with risks of 0.25, 2.0 and 8.5% among women with VL < 50, 50-1000 and > 1000 copies/mL at delivery, respectively (P < 0.001).

CONCLUSIONS

High rates of VS at delivery and low rates of MTCT can be achieved in a routine care setting in sub-Saharan Africa, indicating the effectiveness of currently recommended ART regimens. Women initiating ART late in pregnancy and with high VL appear substantially less likely to achieve VS and require targeted research and programmatic attention.

HIV viral load: a concept analysis and critique

In this article, we examine the concept of HIV viral load and how it has evolved over time (1995-2013) in the field of HIV/AIDS. Although the term viral load is used extensively in this field, few efforts have been directed toward the conceptualization of HIV viral load, which is often left unquestioned, undertheorized, and portrayed as a neutral and objective laboratory value that has remained relatively stable over time--with the exception of progressive advancements in technology, techniques, and sensitivity. The purpose of this article is to apply the evolutionary concept analysis method developed by Rodgers (1989, 2000a) to the concept of HIV viral load. To set the stage, we establish the need for a concept analysis of HIV viral load and provide an overview of the evolutionary view. Then, drawing on the steps proposed by Rodgers (2000a), we outline the process of data collection, management, and analysis. We then offer an in-depth discussion of the findings (attributes, antecedents, and consequences) informed by Wuest's (2000) critical approach to concept analysis. We conclude by highlighting the implications of this analysis for clinical practice, research, and theory.

Effect of in-utero HIV exposure and antiretroviral treatment strategies on measles susceptibility and immunogenicity of measles vaccine

INTRODUCTION

The high burden of maternal HIV-infection in sub-Saharan Africa may affect measles control. We evaluated the effect of in-utero HIV-exposure and antiretroviral treatment (ART) strategies on measles antibody kinetics prior and following measles vaccination.

METHODS

Infants aged 6-12 weeks were enrolled. This included HIV-uninfected infants born to HIV-uninfected (HUU) and HIV-infected mothers (HEU). Additionally, we enrolled perinatal HIV-infected infants with CD4% equal or greater than 25% randomized to deferred-ART until clinically or immunologically indicated (Group-3) or immediate-ART initiation (Group-4). Group-4 was further randomized to interrupt ART at 1 year (Group-4a) or 2 years of age (Group-4b). Additionally, a convenience sample of HIV-infected infants with CD4⁺ less than 25% initiated on immediate-ART was enrolled (Group-5). Measles immunoglobulin-G antibodies were quantified by an indirect enzyme immunoassay with titers 330 mIU/ml or more considered 'sero-protective'. The referent group was HUU-children.

RESULTS

The proportion with sero-protective titers at 7.3 weeks of age was higher in HUU (65.2%) compared with any HIV-infected group (range: 16.7-41.8%), but dropped to less than 17% in all groups at age 19.6 weeks. Twenty-eight weeks following the first measles vaccine, Group-4a was less likely to have sero-protective titers (79.3%) as compared to HUU (91.1%; P<0.0001), Group-3 (95.7%; P=0.003) or Group-4b (92.1%; P=0.018). Although the proportion with sero-protective levels were similar between groups immediately postbooster dose, this was lower in HEU (79.6%; P=0.002) and Group-4a (80.3%; P=0.010) compared with HUU (94.3%) 41-weeks later.

CONCLUSION

Greater waning of immunity among HIV-infected children in whom ART was interrupted and in HEU following a booster-dose, indicate the possible need for further measles-booster doses after 2 years of age in these children.

Pregnancy loss and role of infant HIV status on perinatal mortality among HIV-infected women

BACKGROUND

HIV-infected women, particularly those with advanced disease, may have higher rates of pregnancy loss (miscarriage and stillbirth) and neonatal mortality than uninfected women. Here we examine risk factors for these adverse pregnancy outcomes in a cohort of HIV-infected women in Zambia considering the impact of infant HIV status.

METHODS

A total of 1229 HIV-infected pregnant women were enrolled (2001-2004) in Lusaka, Zambia and followed to pregnancy outcome. Live-born infants were tested for HIV by PCR at birth, 1 week and 5 weeks. Obstetric and neonatal data were collected after delivery and the rates of neonatal (<28 days) and early mortality (<70 days) were described using Kaplan-Meier methods.

RESULTS

The ratio of miscarriage and stillbirth per 100 live-births were 3.1 and 2.6, respectively. Higher maternal plasma viral load (adjusted odds ratio [AOR] for each log10 increase in HIV RNA copies/ml = 1.90; 95% confidence interval [CI] 1.10-3.27) and being symptomatic were associated with an increased risk of stillbirth (AOR = 3.19; 95% CI 1.46-6.97), and decreasing maternal CD4 count by 100 cells/mm3 with an increased risk of miscarriage (OR = 1.25; 95% CI 1.02-1.54). The neonatal mortality rate was 4.3 per 100 increasing to 6.3 by 70 days. Intrauterine HIV infection was not associated with neonatal morality but became associated with mortality through 70 days (adjusted hazard ratio = 2.76; 95% CI 1.25-6.08). Low birth weight and cessation of breastfeeding were significant risk factors for both neonatal and early mortality independent of infant HIV infection.

CONCLUSIONS

More advanced maternal HIV disease was associated with adverse pregnancy outcomes. Excess neonatal mortality in HIV-infected women was not primarily explained by infant HIV infection but was strongly associated with low birth weight and prematurity. Intrauterine HIV infection contributed to mortality as early as 70 days of infant age. Interventions to improve pregnancy outcomes for HIV-infected women are needed to complement necessary therapeutic and prophylactic antiretroviral interventions.

Correlates of mother-to-child transmission of HIV in the United States and Puerto Rico

OBJECTIVE

The goal of this study was to examine associations between demographic, behavioral, and clinical variables and mother-to-child HIV transmission in 15 US jurisdictions for birth years 2005 through 2008.

METHODS

The study used Enhanced Perinatal Surveillance system data for HIV-infected women who gave birth to live infants. Multivariable logistic regression was used to assess variables associated with mother-to-child transmission.

RESULTS

Among 8054 births, 179 infants (2.2%) were diagnosed with HIV infection. Half of the births had at least 1 missed prevention opportunity: 74.3% of infected infants, 52.1% of uninfected infants. Among 7757 mother-infant pairs with sufficient data for analysis, the odds of having an HIV-infected infant were higher for women who received late testing or no prenatal antiretroviral medications (odds ratio: 2.5 [95% confidence interval (CI): 1.5-4.0] and 3.5 [95% CI: 2.0-6.4], respectively). The odds for mothers who breastfed were 4.6 times (95% CI: 2.2-9.8) the odds for those who did not breastfeed. The adjusted odds for women with CD4 counts <200 cells per microliter were 2.4 times (95% CI: 1.4-4.2) those for women with CD4 counts ≥500 cells per microliter. The odds for women who abused substances were twice (95% CI: 1.4-2.9) those for women who did not.

CONCLUSIONS

The odds of having an HIV-infected infant were higher among HIV-infected women who were tested late, had no antiretroviral medications, abused substances, breastfed, or had lower CD4 cell counts. Increases in earlier HIV diagnosis, substance abuse treatment, avoidance of breastfeeding, and use of prenatal antiretroviral medications are critical in eliminating perinatal HIV infections in the United States.

Risk factors for detectable HIV-1 RNA at delivery among women receiving highly active antiretroviral therapy in the women and infants transmission study

BACKGROUND

Detectable HIV-1 RNA at delivery is the strongest predictor of mother-to-child transmission. The risk factors for detectable HIV, including type of regimen, are unknown. We evaluated factors, including highly active antiretroviral (HAART) regimen, associated with detectable HIV-1 RNA at delivery in the Women and Infants Transmission Study (WITS).

METHODS

Data from 630 HIV-1-infected women who enrolled from 1998 to 2005 and received HAART during pregnancy were analyzed. Multivariable analyses examined associations between regimens, demographic factors, and detectable HIV-1 RNA (>400 copies/milliliter) at delivery.

RESULTS

Overall, 32% of the women in the cohort had detectable HIV-1 RNA at delivery. Among the subset of 364 HAART-experienced women, a lower CD4 cell count at enrollment [adjusted odds ratio (AOR) = 1.20 per 100 cells/microL, confidence interval (CI) 1.04 to 1.37] and higher HIV-1 RNA at enrollment (AOR = 1.52 per log10 copies/milliliter, CI 1.32 to 1.75) were significantly associated with detectable HIV-1 RNA levels at delivery. For the 266 HAART-naive women, both lower CD4 cell count at enrollment (AOR = 1.24 per 100 cells/microL, CI 1.05 to 1.48) and higher HIV-1 RNA at enrollment (AOR = 1.35 per log10 copies/milliliter, CI 1.12 to 1.63) were associated with detectable HIV-1 RNA at delivery. In addition, age at delivery (AOR = 0.92 per 10 years older, CI 0.86 to 0.99) and maternal illicit drug use (AOR = 3.15, CI 1.34 to 7.41) were significantly associated with detectable HIV-1 RNA at delivery among HAART-naive women. Type of HAART regimen was not significant in either group.

CONCLUSIONS

Lack of viral suppression at delivery was common in the WITS cohort, but differences by antiretroviral regimen were not identified. Despite a transmission rate below 1% in the last 5 years of the WITS cohort, improved measures to maximize HIV-1 RNA suppression at term among high-risk women are warranted.

Antiretroviral therapy initiation before, during, or after pregnancy in HIV-1-infected women: maternal virologic, immunologic, and clinical response

Background

Pregnancy has been associated with a decreased risk of HIV disease progression in the highly active antiretroviral therapy (HAART) era. The effect of timing of HAART initiation relative to pregnancy on maternal virologic, immunologic and clinical outcomes has not been assessed.

Methods

We conducted a retrospective cohort study from 1997–2005 among 112 pregnant HIV-infected women who started HAART before (N = 12), during (N = 70) or after pregnancy (N = 30).

Results

Women initiating HAART before pregnancy had lower CD4+ nadir and higher baseline HIV-1 RNA. Women initiating HAART after pregnancy were more likely to receive triple-nucleoside reverse transcriptase inhibitors. Multivariable analyses adjusted for baseline CD4+ lymphocytes, baseline HIV-1 RNA, age, race, CD4+ lymphocyte count nadir, history of ADE, prior use of non-HAART ART, type of HAART regimen, prior pregnancies, and date of HAART start. In these models, women initiating HAART during pregnancy had better 6-month HIV-1 RNA and CD4+ changes than those initiating HAART after pregnancy (−0.35 vs. 0.10 log₁₀ copies/mL, P = 0.03 and 183.8 vs. −70.8 cells/mm³, P = 0.03, respectively) but similar to those initiating HAART before pregnancy (−0.32 log₁₀ copies/mL, P = 0.96 and 155.8 cells/mm³, P = 0.81, respectively). There were 3 (25%) AIDS-defining events or deaths in women initiating HAART before pregnancy, 3 (4%) in those initiating HAART during pregnancy, and 5 (17%) in those initiating after pregnancy (P = 0.01). There were no statistical differences in rates of HIV disease progression between groups.

Conclusions

HAART initiation during pregnancy was associated with better immunologic and virologic responses than initiation after pregnancy.

Prior illicit drug use and missed prenatal vitamins predict nonadherence to antiretroviral therapy in pregnancy: adherence analysis A5084

Adherence to antiretroviral therapy (ART) in pregnancy is crucial to optimize its efficacy and minimize mother-to-child transmission. Our objective was to examine adherence patterns to ART and health behaviors during and after pregnancy among HIV-positive women enrolled in A5084, a prospective, observational, multisite study. Between 2002-2005, HIV-infected women between 20 and 34 weeks'gestation completed at least 1 self-reported adherence questionnaire antepartum (AP), and were followed through 12 weeks' postpartum (PP). Questionnaires also addressed tobacco, alcohol, and illicit drugs use. Adherence was defined as reporting not having missed any doses for more than 3 months. Exact McNemar's tests were used for paired binary data and exact logistic regression was used for predictors of nonadherence. We report on 149 women (55% black, 26% Hispanic, 32% less than 25 years, 9% with AIDS, 100% on ART). PP, 31 (21%) women stopped ART and 18 (12%) withdrew from the study. AP, 57% reported adherence to ART and PP, 45% (p = 0.03, n = 87). AP, 11% reported ongoing alcohol use and 23% tobacco use compared to 37% and 30% PP (p < 0.0001, n = 103; p = 0.07, n = 99, respectively). Although 39% ever used marijuana (n = 116) and 25% used illicit drugs (n = 107), few participants reported use during the study. In multivariate analyses, those who had ever used illicit drugs had 5.95 times higher odds (p = 0.002) and those who missed prenatal vitamins had 4.84 times higher odds (p = 0.001) of ART nonadherence. Women reporting a history of illicit drug use and/or having missed prenatal vitamins should be targeted for programs to enhance adherence to ART during pregnancy.

African infants' CCL3 gene copies influence perinatal HIV transmission in the absence of maternal nevirapine

BACKGROUND

Individuals with more copies of CCL3L1 (CCR5 ligand) than their population median have been found to be less susceptible to HIV infection. We investigated whether maternal or infant CCL3L1 gene copy numbers are associated with perinatal HIV transmission when single-dose nevirapine is given for prevention.

METHOD

A nested case-control study was undertaken combining data from four cohorts including 849 HIV-infected mothers and their infants followed prospectively in Johannesburg, South Africa. Access to antiretroviral drugs for the prevention of perinatal transmission differed across the cohorts. Maternal and infant CCL3L1 gene copy numbers per diploid genome (pdg) were determined by real-time polymerase chain reaction for 79 out of 83 transmitting pairs ( approximately 10% transmission rate) and 235 randomly selected non-transmitting pairs.

RESULTS

Higher numbers of infant, but not maternal, CCL3L1 gene copies were associated with reduced HIV transmission (P = 0.004) overall, but the association was attenuated if mothers took single-dose nevirapine or if the maternal viral load was low. Maternal nevirapine was also associated with reduced spontaneously released CCL3 (P = 0.007) and phytohemagglutinin-stimulated CCL3 (P = 0.005) production in cord blood mononuclear cells from uninfected infants.

CONCLUSION

We observed a strong association between higher infant CCL3L1 gene copies and reduced susceptibility to HIV in the absence of maternal nevirapine. We also observed a reduction in newborn CCL3 production with nevirapine exposure. Taken together, we hypothesize that nevirapine may have direct or indirect effects that partly modify the role of the CCR5 ligand CCL3 in HIV transmission, obscuring the relationship between this genetic marker and perinatal HIV transmission.

Effects of antiretroviral therapy on tube-like network formation of human endothelial cells

New guidelines suggest that HIV-infected pregnant women should be offered combination antiretroviral therapy (zidovudine and protease inhibitors) to prevent fetal HIV infection but concerns remain about potential adverse effects for the infant. Prior small case series have suggested an increased risk for hemangioma. In this study we used zidovudine and indinavir, alone or in combination, to assess the effect on an in vitro angiogenesis system for endothelial cells. The increase in capillary tube formation, was associated with a significant increase in vascular endothelial growth factor (VEGF) production. Zidovudine and indinavir used in combination do not further strengthen both endothelial cell tubes formation and VEGF secretion. We conclude that zidovudine and indinavir may induce angiogenesis in an in vitro model.

Care and management of the infant of the HIV-1-infected mother

Mother-to-child transmission of the human immunodeficiency virus continues to be a major global health problem. The pediatric HIV-1 epidemic is fueled by HIV-1 infection in women of childbearing age with vertical transmission in utero or at the time of birth. In resource-rich countries, the birth of an infected child is a sentinel health event signaling a chain of missed opportunities and barriers to prevention. Because the fate and ultimate HIV-infection status of the baby is inextricably linked to the infection status of the mother and her general state of well-being, we provide in this review: 1) background and state-of-the-art management guidelines for optimum maternal care; 2) strategies to minimize the risk of vertical transmission of HIV; and 3) recommendations for managing infants born to HIV-infected women. These are discussed under four case scenarios that obstetric and pediatric providers frequently encounter in their practices.

Mother-to-child transmission of HIV in the United States. Many HIV-infected women are now planning to have children. What are the risks to mother and infant?

OVERVIEW

With the rise in the number of HIV-infected women of childbearing age in the United States, nurses are increasingly likely to be caring for such women. Although the exact mechanism of mother-to-child HIV transmission is unknown, experts believe that it can occur during any of three stages: before birth by microtransfusion of maternal blood across the placenta, during labor and delivery by exposure to maternal cervicovaginal secretions and blood, and after birth through breastfeeding. Treating pregnant women with highly active antiretroviral therapy dramatically reduces the risk of such transmission, but little is known about long-term effects of such therapy on the children. This article reviews the literature on the risk of mother-to-child HIV transmission in the United States and the factors that influence that risk, details current practice recommendations, and discusses implications for nursing.

Antiretroviral therapy 2006: Pharmacology, applications, and special situations

As we approach the completion of the first 25 years of the human immunodeficiency virus (HIV) epidemic, there have been dramatic improvements in the care of patients with HIV infection. These have prolonged life and decreased morbidity. There are twenty currently available antiretrovirals approved in the United States for the treatment of this infection. The medications, including their pharmacokinetic properties, side effects, and dosing are reviewed. In addition, the current approach to the use of these medicines is discussed. We have included a section addressing common comorbid conditions including hepatitis B and C along with tuberculosis.

[Protective and risk factors related to vertical transmission of the HIV-1]

This study aimed to evaluate maternal and fetal factors related to vertical transmission of HIV-1. Participants included 47 mother-child pairs. Behavioral, demographic, and obstetric data were obtained through interviews. Data related to delivery and newborns were collected from registries in the maternity hospitals. During the third trimester of pregnancy, CD4+ T lymphocytes and maternal viral load were measured. Mean age of the mothers was 25 years and 23.4% of the pregnant women were primigravidae. The most prevalent behavioral factor was lack of condom use. 48.9% of the women presented a CD4+ count greater than 500 cells/mm3, and 93.6% belonged to clinical category A. 95.7% of the women received zidovudine prophylaxis during pregnancy or childbirth, and the medication was also administered to all the neonates. 50.0% of patients were submitted to elective cesareans. Despite several risk and protective factors, none of the children was infected. Vertical transmission is an outcome of an imbalance among factors, with a predominance of risk over protective factors.

Nelfinavir plasma concentrations are low during pregnancy

Plasma nelfinavir concentration ratios (CRs) were calculated for all pregnant (n=27) and nonpregnant (n=48) human immunodeficiency virus type 1-infected women receiving the drug who visited our outpatient clinic. In pregnant women, mean and median nelfinavir CRs were significantly lower (P=.02 and P=.04, respectively), and 51% of the CRs were below the clinically relevant threshold of 0.90, compared with 35% of the CRs in nonpregnant women. After we adjusted for confounders, we found that the mean nelfinavir CR was 34% lower in pregnant women (P=.02). With targeted interventions, subsequent CRs in pregnant women showed a significant increase (median increase, 0.31; P=.01).

The role of sexually transmitted diseases in HIV transmission

More than 42 million people worldwide are now infected with HIV, in spite of sustained prevention activities. Although the spread of HIV has been primarily sexual, epidemiological studies have indicated that the efficiency of the spread of HIV is poor, perhaps as infrequently as 1 in every 1,000 episodes of sexual intercourse. However, sexually transmitted diseases (STDs) that cause ulcers or inflammation greatly increase the efficiency of HIV transmission--by increasing both the infectiousness of, and the susceptibility to HIV infection. STDs might be particularly important in the early stages of a localized HIV epidemic, when people with risky sexual behaviour are most likely to become infected. In China, eastern Europe and Russia, there has been a remarkable increase in the incidence of STDs in recent years, and this is reflected in the rapid increase in the spread of HIV in these areas. Targeted STD detection and treatment should have a central role in HIV prevention in these emerging epidemics.

Repeated low-dose mucosal simian immunodeficiency virus SIVmac239 challenge results in the same viral and immunological kinetics as high-dose challenge: a model for the evaluation of vaccine efficacy in nonhuman primates

Simian immunodeficiency virus (SIV) challenge of rhesus macaques provides a relevant model for the assessment of human immunodeficiency virus (HIV) vaccine strategies. To ensure that all macaques become infected, the vaccinees and controls are exposed to large doses of pathogenic SIV. These nonphysiological high-dose challenges may adversely affect vaccine evaluation by overwhelming potentially efficacious vaccine responses. To determine whether a more physiologically relevant low-dose challenge can initiate infection and cause disease in Indian rhesus macaques, we used a repeated low-dose challenge strategy designed to reduce the viral inoculum to more physiologically relevant doses. In an attempt to more closely mimic challenge with HIV, we administered repeated mucosal challenges with 30, 300, and 3,000 50% tissue culture infective doses (TCID(50)) of pathogenic SIVmac239 to six animals in three groups. Infection was assessed by sensitive quantitative reverse transcription-PCR and was achieved following a mean of 8, 5.5, and 1 challenge(s) in the 30, 300, and 3,000 TCID(50) groups, respectively. Mortality, humoral immune responses, and peak plasma viral kinetics were similar in five of six animals, regardless of challenge dose. Interestingly, macaques challenged with lower doses of SIVmac239 developed broad T-cell immune responses as assessed by ELISPOT assay. This low-dose repeated challenge may be a valuable tool in the evaluation of potential vaccine regimes and offers a more physiologically relevant regimen for pathogenic SIVmac239 challenge experiments.

Anesthetic management of the parturient with fever and infection

Fever is a common clinical problem in labor and delivery suites. It can result from a variety of infectious microorganisms, tissue trauma, malignancy, drug administration, and endocrine and immunologic disorders. Infection is the most common cause of fever, reflecting the effect of pyrogens on the hypothalamus. The diagnosis of infection in pregnancy often raises questions about the safety of regional anesthesia in febrile patients. Despite this concern, and lack of universal guidelines, it has now been well established that the presence of infection and fever in labor does not always contraindicate the administration of regional anesthesia.

Quantitation of human immunodeficiency virus type 1 in breast milk

The distribution and stability of human immunodeficiency virus type 1 (HIV-1) in breast milk (BM) components remain largely unknown. Inhibitory effects, if any, of BM on HIV RNA and DNA PCR amplification are poorly understood. We have addressed these issues by using virus-spiked BM samples from HIV-negative women. BM samples from HIV-negative women were spiked with HIV-1 virions or cells containing a single integrated copy of HIV DNA (8E5/LAV). After incubation under different experimental conditions, viral RNA was detected by the Roche Amplicor UltraSensitive assay in whole-milk, skim milk, and lipid fractions. We found excellent correlation between HIV-1 input copy and recovery in whole milk (r = 0.965, P < 0.0001), skim milk (r = 0.972, P < 0.0001), and the lipid fraction (r = 0.905, P < 0.001). PCR inhibition was observed in less than 10% of the spiked samples. Similar levels of inhibition were noted in BM samples collected from HIV-infected women. HIV proviral DNA was detected in BM samples using real-time PCR (linear correlation between the threshold cycle versus log DNA copy number, >0.982). The effects of incubation duration and temperature and repeated freeze-thaw cycles on HIV RNA recovery were analyzed. HIV RNA levels were remarkably stable in whole milk after three freeze-thaw cycles and for up to 30 h at room temperature. Our findings improve the understanding of the dynamics of HIV detection in BM and the conditions for BM sample collection, storage, and processing.

Human immunodeficiency virus in the parturient

Over the last 20 years, the acquired immune deficiency syndrome (AIDS) has grown from a small case series of Pneumocystis carinii infection in four homosexual men to one of the major health problems facing the world today. In the next 5 years, human immunodeficiency virus (HIV) infection is expected to kill more than 2.2 million people. In the United States, women of childbearing age constitute a large percentage of new cases of AIDS. Because of the increased prevalence of HIV in pregnant women, many anesthesiologists encounter these patients in their practice. The safety of regional neuraxial spread has been a concern in the past, nevertheless, recent analysis of the problem has shown that HIV infection in pregnancy does not contraindicate administration of regional anesthesia.

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].

Options for prevention of HIV transmission from mother to child, with a focus on developing countries

Use of antiretroviral drugs among HIV-infected pregnant women in many developed countries has significantly reduced rates of mother-to-child HIV transmission, demonstrating that this route of transmission is amenable to intervention. Prevention of transmission in developing countries has proved to be more difficult, although recent advances in short-course antiretroviral drug interventions have made it an immediate possibility, rather than a distant hope as it was seen to be in the recent past. Non-antiretroviral drug interventions, including washing of the birth canal with antiseptic solution and micronutrient supplementation, have not been found to be effective at interrupting mother-to-child HIV transmission, but may have other benefits for maternal and child health. An important issue for developing countries is prevention of postnatal HIV transmission through breast feeding. In most developing countries, formula feeding is not a reasonable option, given the higher rates of mortality from diarrheal and respiratory disease associated with avoidance of all breast feeding. A promising new line of research has recently been broached with the findings from a study in South Africa, which demonstrated that exclusive breast feeding is associated with a significant reduction in postnatal transmission of HIV.

Transplacental passage of protease inhibitors at delivery

OBJECTIVE

Although combinations of different antiretroviral drugs are increasingly used by pregnant HIV-1-infected women, few human data are available to evaluate in utero protease inhibitors (PI) exposure. The aim of this study was to assess the extent of transplacental passage of PI at delivery.

METHODS

Pregnant women treated with antiretroviral drugs including PI and/or nevirapine were eligible for the study. Placental transfer was determined by comparison of drug concentrations in blood samples simultaneously collected from a peripheral maternal vein and the umbilical cord at delivery. Drug levels were determined by high-performance liquid chromatography.

RESULTS

Thirteen maternal-cord blood sample pairs were evaluable for transplacental passage determination (nine nelfinavir, two ritonavir, one saquinavir, one lopinavir, two nevirapine). Median cord and maternal drug concentrations, respectively, were nelfinavir < 250 and 1110 ng/ml; ritonavir < 250 and 1113 ng/ml; saquinavir < 100 and 350 ng/ml; lopinavir < 250 and 3105 ng/ml and nevirapine 2072 and 2546 ng/ml. The cord-to-maternal blood ratio was extremely low for all PI.

CONCLUSION

PI do not cross the placenta to an appreciable extent and consequently cannot be expected to exert a direct antiviral activity in utero during the whole dosing interval. Limited transfer may result from their high degree of plasma protein binding and their backwards transport through P-glycoprotein, largely expressed in the placenta. In contrast, nevirapine readily crosses the placental barrier. Such considerations may support treatment decisions in pregnant women.

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.

Vertical human immunodeficiency virus type 1--HIV-1--transmission--a review

Several factors appear to affect vertical HIV-1 transmission, dependent mainly on characteristics of the mother (extent of immunodeficiency, co-infections, risk behaviour, nutritional status, immune response, genetical make-up), but also of the virus (phenotype, tropism) and, possibly, of the child (genetical make-up). This complex situation is compounded by the fact that the virus may have the whole gestation period, apart from variable periods between membrane rupture and birth and the breast-feeding period, to pass from the mother to the infant. It seems probable that an extensive interplay of all factors occurs, and that some factors may be more important during specific periods and other factors in other periods. Factors predominant in protection against in utero transmission may be less important for peri-natal transmission, and probably quite different from those that predominantly affect transmission by mothers milk. For instance, cytotoxic T lymphocytes will probably be unable to exert any effect during breast-feeding, while neutralizing antibodies will be unable to protect transmission by HIV transmitted through infected cells. Furthermore, some responses may be capable of controlling transmission of determined virus types, while being inadequate for controlling others. As occurrence of mixed infections and recombination of HIV-1 types is a known fact, it does not appear possible to prevent vertical HIV-1 transmission by reinforcing just one of the factors, and probably a general strategy including all known factors must be used. Recent reports have brought information on vertical HIV-1 transmission in a variety of research fields, which will have to be considered in conjunction as background for specific studies.

The cost effectiveness of voluntary prenatal and routine newborn HIV screening in the United States

OBJECTIVE

To evaluate the cost effectiveness of voluntary prenatal and routine postnatal HIV screening in the cohort of pregnant women and newborns in the United States.

DESIGN

Cost-effectiveness analysis. We developed a decision model to analyze the cost effectiveness of enhanced prenatal screening and routine newborn screening for HIV. We also analyzed the incremental cost effectiveness of routine newborn screening when improved voluntary prenatal screening is already in place.

PARTICIPANTS

Analysis of the cohort of pregnant women and newborns in the United States.

INTERVENTIONS

Enhanced prenatal screening, or routine newborn screening for HIV.

MAIN OUTCOME MEASURES

Infections averted, life expectancy, costs, and incremental cost effectiveness.

RESULTS

Improved participation in voluntary prenatal HIV screening would result in an additional 1.1 million women being screened annually, would identify an additional 527 HIV-infected mothers annually, would avert 150 infections in newborns, and would cost $8,900 U.S. per life-year gained. Routine newborn HIV screening would test 3.9 million infants annually, would identify 1061 HIV-infected mothers, would avert 266 infections in newborns, and would cost $7,000 U.S. per life-year gained. If improved voluntary prenatal screening is already in place, routine newborn screening would avert an additional 135 infections in newborns, at an incremental cost of $10, 600 U.S. per life-year gained. The screening programs are likely to be cost effective over a wide range of assumptions regarding key factors in the analysis.

CONCLUSIONS

Improved voluntary prenatal HIV screening of women and routine screening of newborns are cost effective. Routine newborn screening becomes less attractive as the rate of voluntary prenatal screening increases. Improved participation in voluntary prenatal screening has the added benefit that mothers maintain their right to determine whether they are tested for HIV.