Diagnosis of pediatric human immunodeficiency virus infection in resource-constrained settings

Laboratory support of global health research

Laboratory generated data are used in support of several types of global health research. Routinely obtained clinical diagnostic data are used for disease surveillance, epidemiologic analysis of frequencies and trends, health outcomes research, and sponsored research projects. Clinical data from research laboratories is also collected in support of sponsored research projects. Whether the initial purpose of the testing is in support of research protocols or the data are retrospectively reviewed, the quality of the laboratory data is essential to drawing correct conclusions. The types and use of data generated by on-site, routine diagnostic, research diagnostic and basic science laboratories will be described, with a focus on quality-related issues. Full integration of laboratory management as a partner is essential to successful research planning and execution.

Nonvirologic algorithms for predicting HIV infection among HIV-exposed infants younger than 12 weeks of age

BACKGROUND

Early initiation of antiretroviral therapy has been shown to reduce mortality among perinatally HIV-infected infants, but availability of virologic testing remains limited in many settings.

METHODS

We collected cross-sectional data from mother-infant pairs in three primary care clinics in Lusaka, Zambia, to develop predictive models for HIV infection among infants younger than 12 weeks of age. We evaluated algorithm performance for all possible combinations of selected characteristics using an iterative approach. In primary analysis, we identified the model with the highest combined sensitivity and specificity.

RESULTS

Between July 2009 and May 2011, 822 eligible HIV-infected mothers and their HIV-exposed infants were enrolled; of these, 44 (5.4%) infants had HIV diagnosed. We evaluated 382,155,260 different characteristic combinations for predicting infant HIV infection. The algorithm with the highest combined sensitivity and specificity required 5 of the following 7 characteristic thresholds: infant CD8 percentage >22; infant CD4 percentage ≤44; infant weight-for-age Z score ≤0; infant CD4 ≤1600 cells/µL; infant CD8 >2200 cells/µL; maternal CD4 ≤600 cells/µL; and mother not currently using antiretroviral therapy for HIV treatment. This combination had a sensitivity of 90.3%, specificity of 78.4%, positive predictive value of 22.4%, negative predictive value of 99.2% and area under the curve of 0.844.

CONCLUSION

Predicting HIV infection in HIV-exposed infants in this age group is difficult using clinical and immunologic characteristics. Expansion of polymerase chain reaction capacity in resource-limited settings remains urgently needed.

Presumptive diagnosis of severe HIV infection to determine the need for antiretroviral therapy in children less than 18 months of age

OBJECTIVE

To develop a new algorithm for the presumptive diagnosis of severe disease associated with human immunodeficiency virus (HIV) infection in children less than 18 months of age for the purpose of identifying children who require antiretroviral therapy (ART).

METHODS

A conditional probability model was constructed and non-virologic parameters in various combinations were tested in a hypothetical cohort of 1000 children aged 6 weeks, 6 months and 12 months to assess the sensitivity, specificity, and positive and negative predictive values of these algorithms for identifying children in need of ART. The modelled parameters consisted of clinical criteria, rapid HIV antibody testing and CD4+ T-lymphocyte (CD4) count.

FINDINGS

In children younger than 18 months, the best-performing screening algorithm, consisting of clinical symptoms plus antibody testing plus CD4 count, showed a sensitivity ranging from 71% to 80% and a specificity ranging from 92% to 99%. Positive and negative predictive values were between 61% and 97% and between 95% and 96%, respectively. In the absence of virologic tests, this alternate algorithm for the presumptive diagnosis of severe HIV disease makes it possible to correctly initiate ART in 91% to 98% of HIV-positive children who are at highest risk of dying.

CONCLUSION

The algorithms presented in this paper have better sensitivity and specificity than clinical parameters, with or without rapid HIV testing, for the presumptive diagnosis of severe disease in HIV-positive children less than 18 months of age. If implemented, they can increase the number of HIV-positive children successfully initiated on ART.

Inadequate coordination of maternal and infant HIV services detrimentally affects early infant diagnosis outcomes in Lilongwe, Malawi

OBJECTIVE

To assess the continuity of care and outcome of pediatric HIV prevention, testing, and treatment services, focusing on early infant diagnosis with DNA polymerase chain reaction (PCR).

DESIGN

A retrospective observational cohort.

METHODS

Maternal HIV antibody, infant HIV DNA PCR test results, and outcome data from HIV-infected infants from the prevention of mother-to-child transmission, early infant diagnosis, and pediatric HIV treatment programs operating in Lilongwe, Malawi, between 2004 and 2008 were collected, merged, and analyzed.

RESULTS

Of the 14,669 pregnant women who tested HIV antibody positive, 7875 infants (53.7%) received HIV DNA PCR testing. One thousand eighty-four infants (13.8%) were HIV infected. Three hundred twenty (29.5%) children enrolled into pediatric HIV care, with 202 (63.1%) at the Baylor Center of Excellence. Among these, antiretroviral therapy was initiated on 110 infants (54.5%) whose median age was 9.1 months (interquartile range, 5.4-13.8) and a median of 2.5 months (interquartile range, 1.4-5.2) after HIV clinic registration. Sixty-nine HIV-infected infants (34.2%) died or were lost by December 2008. Initiation of antiretroviral therapy increased the likelihood of survival 7-fold (odds ratio, 7.1; 95% confidence interval, 3.68 to 13.70).

CONCLUSIONS

Separate programs for maternal and infant HIV prevention and care services demonstrated high attrition rates of HIV-exposed and HIV-infected infants, elevated levels of mother-to-child transmission, late infant diagnosis, delayed pediatric antiretroviral therapy initiation, and high HIV-infected infant mortality. Antiretroviral therapy increased HIV-infected infant survival, emphasizing the urgent need for improved service coordination and strategies that increase access to infant HIV diagnosis, improve patient retention, and reduce antiretroviral therapy initiation delays.

University leadership for innovation in global health and HIV/AIDS diagnostics

Medical products used in the developed world often fail to adequately serve resource-limited settings where electricity, transportation and health care workers are not readily available. We suggest that the problem is not only a lack of coordinated financial resources to purchase existing medical products, but also a lack of products that are specifically designed for resource-limited settings. While donor organisations with a focus on global health are increasingly willing to bear the additional financial risk for the research and development of such high-impact medical products, corporations are still reluctant to take their best scientists and engineers away from more commercially attractive projects. Universities, on the other hand, given their teaching and research missions, are well positioned to engage in such high-risk development projects. A group of biomedical, engineering, business and social science researchers at Northwestern University (NU) propose a creative model to address significant social and health needs. The team's initial product focus is a rapid test for diagnosing infants with HIV. The NU model aligns the incentives and expertise of industry, donors and academia to innovate medical products, such as the infant HIV diagnostic test, for resource-limited settings.

Routine offering of HIV testing to hospitalized pediatric patients at university teaching hospital, Lusaka, Zambia: acceptability and feasibility

OBJECTIVES

The difficulties diagnosing infants and children with HIV infection have been cited as barriers to increasing the number of children receiving antiretroviral therapy worldwide.

DESIGN

We implemented routine HIV antibody counseling and testing for pediatric patients hospitalized at the University Teaching Hospital, a national reference center, in Lusaka, Zambia. We also introduced HIV DNA polymerase chain reaction (PCR) testing for early infant diagnosis.

METHODS

Caregivers/parents of children admitted to the hospital wards were routinely offered HIV counseling and testing for their children. HIV antibody positive (HIV+) children <18 months of age were tested with PCR for HIV DNA.

RESULTS

From January 1, 2006, to June 30, 2007, among 15,670 children with unknown HIV status, 13,239 (84.5%) received counseling and 11,571 (87.4%) of those counseled were tested. Overall, 3373 (29.2%) of those tested were seropositive. Seropositivity was associated with younger age: 69.6% of those testing HIV antibody positive were <18 months of age. The proportion of counseled children who were tested increased each quarter from 76.0% in January to March 2006 to 88.2% in April to June 2007 (P < 0.001). From April 2006 to June 2007, 1276 PCR tests were done; 806 (63.2%) were positive. The rate of PCR positivity increased with age from 22% in children <6 weeks of age to 61% at 3-6 months and to 85% at 12-18 months (P < 0.001).

CONCLUSIONS

Routine counseling and antibody testing of pediatric inpatients can identify large numbers of HIV-seropositive children in high prevalence settings. The high rate of HIV infection in hospitalized infants and young children also underscores the urgent need for early infant diagnostic capacity in high prevalence settings.

LTR real-time PCR for HIV-1 DNA quantitation in blood cells for early diagnosis in infants born to seropositive mothers treated in HAART area (ANRS CO 01)

HIV-1 diagnosis in babies born to seropositive mothers is one of the challenges of HIV epidemics in children. A simple, rapid protocol was developed for quantifying HIV-1 DNA in whole blood samples and was used in the ANRS French pediatric cohort in conditions of prevention of mother-to-child transmission. A quantitative HIV-1 DNA protocol (LTR real-time PCR) requiring small blood volumes was developed. First, analytical reproducibility was evaluated on 172 samples. Results obtained on blood cell pellets and Ficoll-Hypaque separated mononuclear cells were compared in 48 adult HIV-1 samples. Second, the protocol was applied to HIV-1 diagnosis in infants in parallel with plasma HIV-RNA quantitation. This prospective study was performed in children born between May 2005 and April 2007 included in the ANRS cohort. The assay showed good reproducibility. The 95% detection cut-off value was 6 copies/PCR, that is, 40 copies/10(6) leukocytes. HIV-DNA levels in whole blood were highly correlated with those obtained after Ficoll-Hypaque separation (r = 0.900, P < 0.0001). A total of 3,002 specimens from 1,135 infants were tested. The specificity of HIV-DNA and HIV-RNA assays was 100%. HIV-1 infection was diagnosed in nine infants before age 60 days. HIV-DNA levels were low, underlining the need for sensitive assays when highly active antiretroviral therapy (HAART) has been given. The performances of this HIV-DNA assay showed that it is adapted to early diagnosis in children. The results were equivalent to those of HIV-RNA assay. HIV-DNA may be used even in masked primary infection in newborns whose mothers have received HAART.

Correlates of adherence to antiretroviral therapy in HIV-infected children in Lomé, Togo, West Africa

We assessed pediatric adherence to antiretroviral therapy (ART) and examined associated factors among children in Togo, West Africa. Structured interviews of caregivers of consecutively enrolled HIV-infected children receiving ART in three HIV/AIDS care centers in Lome, Togo were conducted. Child perfect adherence reflected caregivers' report of no antiretroviral drug doses missed neither in the past 4 days nor in the month before the interview. A total of 74 ART-treated children were included (median age 6 years). Of these, 42% of caregivers declared perfect adherence. In univariate analyses, the major factors relating to child non-adherence were: being female, living in an individual setting (vs. compound with enlarged family), receiving other ART than an NNRT-based regimen, drug regimens with six pills/spoons or more per day, caregiver other than biological parent, caregiver not declaring HIV-status, not participating to support groups and having perceived difficulty of antiretroviral (ARV) administration. In multivariate analysis, female gender, living in an individual setting, receiving other than NNRTI-based regimen and caregivers' perceived difficulty of ARV administration remained independently associated with the reported child's non-adherence. These data show low rates of perfect adherence to ART in children in West Africa, influenced by child and caregiver characteristics and suggest a need for counseling and education interventions as well as continuous psychological and social support.

Preventing mother-to-child transmission of HIV in resource-limited settings: the Elizabeth Glaser Pediatric AIDS Foundation experience

OBJECTIVES

In September 1999, the Elizabeth Glaser Pediatric AIDS Foundation initiated a multicountry, service-based programmatic effort in the developing world to reduce perinatally acquired HIV infection. We review 6(1/2) years of one of the world's largest programs for the prevention of mother-to-child transmission (PMTCT) of HIV.

METHODS

Each PMTCT facility records patient data in antenatal clinics and labor and delivery settings about counseling, testing, HIV status, and antiretroviral prophylaxis and submits the data to foundation staff.

RESULTS

More than 2.6 million women have accessed foundation-affiliated services through June 2006. Overall, 92.9% of women who received antenatal care or were eligible for PMTCT services in labor and delivery have been counseled, and 82.8% of those counseled accepted testing. Among women identified as HIV positive, 75.0% received antiretroviral prophylaxis (most a single dose of nevirapine), as did 45.6% of their infants.

CONCLUSIONS

The foundation's experience has demonstrated that opt-out testing, supplying mothers with medication at time of diagnosis, and providing the infant dose early have measurably improved program efficiency. PMTCT should be viewed as an achievable paradigm and an essential part of the continuum of care.

Provision of care following prevention of mother-to-child HIV transmission services in resource-limited settings

OBJECTIVE

To evaluate the provision of care for mother and child after institution of prevention of mother-to-child transmission (PMTCT) of HIV services.

DESIGN

As part of an effort to improve services, we undertook a review of our multicountry PMTCT program.

METHODS

Review of key indicators from our PMTCT database and reporting practices from January 2005 to June 2006 throughout 18 resource-limited countries.

RESULTS

1 066 606 pregnant women were counseled and tested, and 102 336 tested HIV-positive. Antiretroviral prophylaxis was dispensed to 81 384 mothers and 52 342 HIV-exposed infants. From available reporting, 1388 pregnant women were dispensed antiretroviral drugs for treatment and 9060 children received cotrimoxazole prophylaxis at 6 weeks.

CONCLUSIONS

PMTCT services are integrated into maternal-child health services but adult and pediatric care and treatment programs often function independently, without coordination or linkages. Integrating care into maternal-child health services and linking mother's HIV status to child are necessary for HIV-infected mothers and HIV-exposed children to receive appropriate follow-up and treatment.

Site-specific interventions to improve prevention of mother-to-child transmission of human immunodeficiency virus programs in less developed settings

This article reviews the experiences of programs designed to provide access to prevention of mother-to-child transmission services with the goal of improving services in resource-constrained settings. The article reports new data from the Elizabeth Glaser Pediatric AIDS Foundation's prevention of mother-to-child transmission program in sub-Saharan Africa, which has provided human immunodeficiency virus testing to more than 1,300,000 pregnant women and antiretroviral prophylaxis to 134,000 human immunodeficiency virus-infected pregnant women and more than 78,000 human immunodeficiency virus-exposed infants. Review of qualitative program data highlights the practical innovations that sites are implementing to improve the uptake of prevention of mother-to-child transmission services. Recommendations discussed include opt-out counseling and testing, rapid human immunodeficiency virus testing in antenatal care, counseling and testing in maternity, and provision of antiretroviral prophylaxis for mother and infant at the time of human immunodeficiency virus testing. Successful programmatic innovations need to be disseminated widely as more aggressive prevention strategies must be implemented to increase access to more than 10% of pregnant women worldwide.

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.