Steven Nesheim

Impact of zidovudine use on risk and risk factors for perinatal transmission of HIV

Objectives:To evaluate the impact of perinatal zidovudine use on the risk of perinatal transmission of HIV and to determine risk factors for transmission among women using perinatal zidovudine. Design:Prospective cohort study of 1533 children born to HIV-infected women between 1985 and 1995 in four US cities. Methods:The association of potential risk factors with perinatal HIV transmission was assessed with univariate and multivariate statistics. Results:The overall transmission risk was 18% [95% confidence interval (CI), 16–21]. Factors associated with transmission included membrane rupture > 4 h before delivery [relative risk (RR), 2.1; 95% CI, 1.6–2.7], gestational age < 37 weeks (RR, 1.8; 95% CI, 1.4–2.2), maternal CD4+ lymphocyte count < 500 × 106cells/l (RR, 1.7; 95% CI, 1.3–2.2), birthweight < 2500 g (RR, 1.7; 95% CI, 1.3–2.1), and antenatal and neonatal zidovudine use (RR, 0.6; 95% CI, 0.4–0.9). For infants exposed to zidovudine antenatally and neonatally, the transmission risk was 13% overall but was significantly lower following shorter duration of membrane rupture (7%) and term delivery (9%). The transmission risk declined from 22% before 1992 to 11% in 1995 (P < 0.001) in association with increasing zidovudine use and changes in other risk factors. Conclusions:Perinatal HIV transmission risk has declined with increasing perinatal zidovudine use and changes in other factors. Further reduction in transmission for women taking zidovudine may be possible by reducing the incidence of other potentially modifiable risk factors, such as long duration of membrane rupture and prematurity.

Virologic and Immunologic Outcomes after 24 Weeks in HIV Type 1-Infected Adolescents Receiving Highly Active Antiretroviral Therapy

BACKGROUND Adolescents represent the fastest growing demographic group of new human immunodeficiency virus (HIV) infections in the United States. At present, there is little information available about their response to therapy. METHODS We studied 120 adolescents infected via high-risk behaviors who began receiving highly active antiretroviral therapy (HAART), to determine their virologic and immunologic response to therapy. RESULTS Subjects were enrolled at 28 sites of the Pediatric Acquired Immunodeficiency Syndrome Clinical Trials Group. After 16-24 weeks of HAART, 59% of subjects had reproducible undetectable virus loads, according to repeat measurements (virologic success). As enumerated by flow-cytometric analysis, increases in levels of CD4 helper cells (both naive and memory) and decreases in levels of CD8 suppressor cells were observed. Partial restoration of some immunologic parameters for patients who did not achieve virologic success was also observed, but to a more limited extent than for adolescents with virologic success. Adherence to HAART was the only predictor of achieving undetectable virus loads. CONCLUSIONS Adolescents have the capacity to improve their immunologic status with HAART. Lower than expected success in virologic control is related to lack of adherence, and efforts to improve treatment outcome must stress measures to assure adherence to medication.

Trends in Opportunistic Infections in the Pre–and Post–Highly Active Antiretroviral Therapy Eras Among HIV-Infected Children in the Perinatal AIDS Collaborative Transmission Study, 1986–2004

OBJECTIVE. We sought to determine the impact of highly active antiretroviral therapy on the incidence and prevalence of opportunistic infections in HIV-infected children. METHODS. Children born from 1986 to 1998 were monitored until 2004 in the Perinatal AIDS Collaborative Transmission Study, sponsored by the Centers for Disease Control and Prevention. We determined the pre–highly active antiretroviral therapy and post–highly active antiretroviral therapy (before and after January 1, 1997, respectively) incidence rates of opportunistic infections among HIV-infected children and characterized the temporal decreases in percentages of CD4+ cells and the mortality rates among patients with and those without incident opportunistic infections. RESULTS. The overall opportunistic infection incidence declined from 14.4 to 1.1 cases per 100 patient-years; statistically significant reductions were seen in the incidence of the most common opportunistic infections, including Pneumocystis jiroveci pneumonia (5.8 vs 0.3 cases per 100 patient-years), recurrent bacterial infections (4.7 vs 0.2 cases per 100 patient-years), extraocular cytomegalovirus infection (1.4 vs 0.1 cases per 100 patient-years), and disseminated nontuberculous mycobacterial infection (1.3 vs 0.2 cases per 100 patient-years). Kaplan-Meier analysis of time from birth to the first opportunistic infection illustrated more-rapid acquisition of opportunistic infections by HIV-infected children born in the pre–highly active antiretroviral therapy era than by those born later. In the first 3 years of life, there was a faster decline in the percentage of CD4+ cells among children with opportunistic infections. The mortality rate was significantly higher among children with opportunistic infections. CONCLUSIONS. Reduction in the incidence of opportunistic infections and prolongation of the time to the first opportunistic infection were noted during the post–highly active antiretroviral therapy era. Children who experienced opportunistic infections had higher mortality rates than did those who did not. Younger children (<3 years) who experienced opportunistic infections had faster declines in percentages of CD4+ T cells.

Thymic Dysfunction and Time of Infection Predict Mortality in Human Immunodeficiency Virus-Infected Infants

The effect of human immunodeficiency virus (HIV)-induced thymic dysfunction (TD) on mortality was studied in 265 infected infants in the CDC Perinatal AIDS Collaborative Transmission Study. TD was defined as both CD4 and CD8 T cell counts below the 5th percentile of joint distribution for uninfected infants within 6 months of life. The 40 HIV-infected infants with TD (15%) had a significantly greater mortality than did the 225 children without TD (44% vs. 9% within 2 years). Infants with TD infected in utero had higher mortality than did those infected intrapartum (70% vs. 37% within 2 years), while no significant difference was noted between infants without TD with either mode of transmission. The TD profile was independent of plasma virus load. Virus-induced TD by particular HIV strains and the time of transmission are likely to explain the variation in pathogenesis and patterns of disease progression and suggest the need for early aggressive therapies for HIV-infected infants with TD.

Dyslipidemia among perinatally HIV-infected children enrolled in the PACTS-HOPE cohort, 1999-2004: a longitudinal analysis.

Background: Protease inhibitor (PI)-containing regimens have led to improved survival among HIV-infected children. However, adverse effects, including dyslipidemia, may put children at risk for cardiovascular disease. Methods: Serum cholesterol and triglyceride levels were recorded on perinatally HIV-infected children participating in the PACTS-HOPE cohort (1999-2004). Hypercholesterolemia (HC) was defined as cholesterol ≥200 mg/dL and hypertriglyceridemia (HT) as triglycerides ≥150 mg/dL. HC and HT were modeled over time using generalized estimating equations. Results: For 178 children, 47% met criteria for HC and 67% for HT at least once during the study period. In generalized estimating equation models, PI use, undetectable viral load, and immunologic category 3 were independent predictors of HC. HT was significantly associated with PI use and body mass index (BMI) ≥90th percentile for age and gender. Among children on PI-containing regimens, HC was significantly associated with multiple PIs and undetectable viral load; HT was predicted by body mass index ≥90th percentile and ritonavir use. The prevalence of clinical lipodystrophy was 5.6% (10/178). Conclusions: Children on PI-containing regimens have a higher risk of both HC and HT. Lipid levels should be measured regularly in children on antiretroviral treatment. Interventions such as diet, exercise, or lipid-lowering drug therapy may benefit some children.

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.

Lack of evidence of mitochondrial dysfunction in the offspring of HIV-infected women. Retrospective review of perinatal exposure to antiretroviral drugs in the Perinatal AIDS Collaborative Transmission Study.

Abstract: A recent report suggesting mitochondrial dysfunction among eight HIV‐exposed but uninfected children exposed perinatally to nucleoside reverse transcriptase inhibitors (NRTIs) prompted a review within the Perinatal AIDS Collaborative Transmission Study (PACTS). A standardized retrospective review was conducted of 118 deaths at <5 years. Deaths were classified as unrelated to mitochondrial dysfunction (Class 1), unlikely related (Class 2), possibly related (Class 3), or likely related or proven (Class 4). Among 35 deaths recorded in HIV‐uninfected or indeterminate children, none were classified in either Class 2, 3, or 4. We also reviewed signs or symptoms consistent with possible mitochondrial dysfunction among 1,954 living uninfected children. Only one child was in Class 3 and two siblings were in Class 2; none had perinatal antiretroviral drug exposure. We found no evidence indicating that uninfected infants exposed to perinatal NRTIs died of mitochondrial disorders or that living exposed children had symptoms of mitochondrial dysfunction.

A Framework for Elimination of Perinatal Transmission of HIV in the United States

The availability of effective interventions to prevent mother-to-child HIV transmission and the significant reduction in the number of HIV-infected infants in the United States have led to the concept that elimination of mother-to-child HIV transmission (EMCT) is possible. Goals for elimination are presented. We also present a framework by which elimination efforts can be coordinated, beginning with comprehensive reproductive health care (including HIV testing) and real-time case-finding of pregnancies in HIV-infected women, and conducted through the following: facilitation of comprehensive clinical care and social services for women and infants; case review and community action; allowing continuous quality research in prevention and long-term follow-up of HIV-exposed infants; and thorough data reporting for HIV surveillance and EMCT evaluation. It is emphasized that EMCT will not be a one-time accomplishment but, rather, will require sustained effort as long as there are new HIV infections in women of childbearing age.

Quantitative RNA testing for diagnosis of HIV-infected infants.

Quantitative HIV RNA testing was used for diagnosis in 156 HIV-exposed non-breast-fed infants at less than 6 months of age (54 infected, 102 uninfected) enrolled in the Perinatal AIDS Collaborative Transmission Study. Sensitivity was 29% in the first week, 79% at 8 to 28 days of age, and >90% at 29 days of age and thereafter; specificity was 100% in all periods, except at 29 to 60 days of age, when specificity was 93%. Neither sensitivity nor specificity was significantly affected by maternal or infant zidovudine (ZDV) treatment, even though infant viral loads were lower during the first 6 weeks in infants who received perinatal ZDV prophylaxis (p = .005). Paired analysis of DNA and RNA measurements revealed no advantage for either test. Quantitative RNA testing can be used for diagnosis in HIV-exposed infants, recognizing the chance for a false-positive test result. It may be most useful as a confirmatory test in infants with another positive diagnostic test result.

Antiretroviral Resistance Mutations among Pregnant Human Immunodeficiency Virus Type 1–Infected Women and Their Newborns in the United States: Vertical Transmission and Clades

To assess the impact of antiretroviral resistance on perinatal transmission prevention efforts, human immunodeficiency virus type 1 (HIV-1) genotypic resistance testing was done for 220 HIV-1-infected, zidovudine (AZT)-exposed pregnant women and 24 of their infected infants. The women were prospectively enrolled in 4 US cities in 1991-1997. Phylogenetic and sequencing analyses revealed 5 women with non-clade B infections traced to western African origins. AZT-associated mutations were detected in 17.3% of pregnant women, whereas genotypic resistance to nonnucleoside reverse-transcriptase inhibitors and protease inhibitors was infrequent. No significant association was detected between perinatal transmission and the presence of either AZT or nucleoside reverse-transcriptase inhibitor resistance-associated mutations. AZT resistance mutations were detected in 2 (8.3%) neonatal samples, but the mutation pattern was not identical to the mothers. Although no effect of viral resistance on mother-infant transmission was demonstrated, the advent of more-potent drug classes and the potential for the rapid emergence of resistance warrant prospective surveillance.