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Welcome to the CIDRZ Published Research Collection. This collection serves as a central repository of peer-reviewed publications authored, co-authored, or supported by the Centre for Infectious Disease Research in Zambia (CIDRZ). It provides open access to scientific knowledge that contributes to public health, clinical research, and evidence-based policy in Zambia and beyond.
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Item Effectiveness of a city-wide program to prevent mother-to-child HIV transmission in Lusaka, Zambia.(2005-Aug-12) Stringer JS; Sinkala M; Maclean CC; Levy J; Kankasa C; Degroot A; Stringer EM; Acosta EP; Goldenberg RL; Vermund SH; Schools of Medicine and Public Health, University of Alabama at Birmingham, USA. stringer@cidrz.org; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To determine the population effectiveness of a city-wide perinatal HIV prevention program. DESIGN: An anonymous surveillance of newborn cord blood for HIV serology and nevirapine (NVP). METHODS: All 10 public-sector delivery centers in Lusaka, Zambia participated. All mother-infant pairs delivering during the 12-week surveillance period at the participating centers and who received antenatal care at a public-sector facility in Lusaka were included in the study. The main outcome measure was population NVP coverage, defined as the proportion of HIV-infected women and HIV-exposed infants in the population that ingested NVP. RESULTS: Of 8787 women in the surveillance population, 7204 (82%) had been offered antenatal HIV testing, of which 5149 (71%) had accepted, and of which 5129 (99%) had received a result. Overall, 2257 of 8787 (26%) were cord seropositive. Of the 1246 (55%) cord blood seropositive women who received an antenatal HIV test result, 1112 (89%) received a positive result; the other 134 comprise seroconverters and clerical errors. Only 751 of 1112 (68%) women who received a positive antenatal test result and a NVP tablet for ingestion at labor onset had NVP detected in the cord blood (i.e., maternal non-adherence rate was 32%). A total of 675 infants born to 751 adherent mothers (90%) received NVP before discharge. Thus, only 675 of 2257 (30%) seropositive mother-infant pairs in the surveillance population received both a maternal and infant dose of NVP. CONCLUSIONS: Successful perinatal HIV prevention requires each mother-infant pair to negotiate a cascade of events that begins with offering HIV testing and continues through adherence to the prescribed regimen. This novel surveillance demonstrates that failures occur at each step, resulting in reduced coverage and diminished program effectiveness.Item Early clinical and immune response to NNRTI-based antiretroviral therapy among women with prior exposure to single-dose nevirapine.(2007-May-11) Chi BH; Sinkala M; Stringer EM; Cantrell RA; Mtonga V; Bulterys M; Zulu I; Kankasa C; Wilfert C; Weidle PJ; Vermund SH; Stringer JS; Centre for Infectious Disease Research in Zambia, Zambia. bchi@cidrz.org; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To determine whether prior exposure to single-dose nevirapine (NVP) for prevention of mother-to-child HIV transmission (PMTCT) is associated with attenuated CD4 cell response, death, or clinical treatment failure in women starting antiretroviral therapy (ART) containing non-nucleoside reverse transcriptase inhibitors (NNRTI). METHODS: Open cohort evaluation of outcomes for women in program sites across Zambia. HIV treatment was provided according to Zambian/World Health Organization guidelines. RESULTS: Peripartum NVP exposure status was known for 6740 women initiating NNRTI-containing ART, of whom 751 (11%) reported prior use of NVP for PMTCT. There was no significant difference in mean CD4 cell change between those exposed or unexposed to NVP at 6 (+202 versus +182 cells/microl; P = 0.20) or 12 (+201 versus +211 cells/microl; P = 0.60) months. Multivariable analyses showed no significant differences in mortality [adjusted hazard ratio (HR), 1.2; 95% confidence interval (CI), 0.8-1.8] or clinical treatment failure (adjusted HR, 1.1; 95% CI, 0.8-1.5). Comparison of recent NVP exposure with remote exposure suggested a less favorable CD4 cell response at 6 (+150 versus +219 cells/microl; P = 0.06) and 12 (+149 versus +215 cells/microl; P = 0.39) months. Women with recent NVP exposure also had a trend towards elevated risk for clinical treatment failure (adjusted HR, 1.6; 95% CI, 0.9-2.7). CONCLUSION: Exposure to maternal single-dose NVP was not associated with substantially different short-term treatment outcomes. However, evidence was suggestive that exposure within 6 months of ART initiation may be a risk factor for poor treatment outcomes, highlighting the importance of ART screening and initiation early in pregnancy.Item A randomized trial of the intrauterine contraceptive device vs hormonal contraception in women who are infected with the human immunodeficiency virus.(2007-Aug) Stringer EM; Kaseba C; Levy J; Sinkala M; Goldenberg RL; Chi BH; Matongo I; Vermund SH; Mwanahamuntu M; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. eli@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: The purpose of this study was to determine whether the intrauterine contraceptive device (IUD) is effective and safe among women who are infected with the human immunodeficiency virus (HIV). STUDY DESIGN: We randomly assigned 599 postpartum, HIV-infected women in Zambia to receive either a copper IUD or hormonal contraception and followed them for at least 2 years. RESULTS: Women who were assigned randomly to hormonal contraception were more likely to become pregnant than those who were assigned randomly to receive an IUD (rate, 4.6/100 vs 2.0/100 woman-years; hazards ratio, 2.4; 95% CI, 1.3-4.7). One woman who was assigned to the IUD experienced pelvic inflammatory disease (crude rate, 0.16/100 woman-years; 95% CI, 0.004-868); there was no pelvic inflammatory disease among those women who were assigned to hormonal contraception. Clinical disease progression (death or CD4+ lymphocyte count dropping below 200 cells/microL) was more common in women who were allocated to hormonal contraception (13.2/100 woman-years) than in women who were allocated to the IUD (8.6/100 woman-years; hazard ratio, 1.5; 95% CI, 1.04-2.1). CONCLUSION: The IUD is effective and safe in HIV-infected women. The unexpected observation that hormonal contraception was associated with more rapid HIV disease progression requires urgent further study.Item Clinical outcomes and CD4 cell response in children receiving antiretroviral therapy at primary health care facilities in Zambia.(2007-Oct-24) Bolton-Moore C; Mubiana-Mbewe M; Cantrell RA; Chintu N; Stringer EM; Chi BH; Sinkala M; Kankasa C; Wilson CM; Wilfert CM; Mwango A; Levy J; Abrams EJ; Bulterys M; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)CONTEXT: The Zambian Ministry of Health provides pediatric antiretroviral therapy (ART) at primary care clinics in Lusaka, where, despite scale-up of perinatal prevention efforts, many children are already infected with the human immunodeficiency virus (HIV). OBJECTIVE: To report early clinical and immunologic outcomes of children enrolled in the pediatric treatment program. DESIGN, SETTING, AND PATIENTS: Open cohort assessment using routinely collected clinical and outcome data from an electronic medical record system in use at 18 government primary health facilities in Lusaka, Zambia. Care was provided primarily by nurses and clinical officers ("physician extenders" akin to physician assistants in the United States). Patients were children (<16 years of age) presenting for HIV care between May 1, 2004, and June 29, 2007. INTERVENTION: Three-drug ART (zidovudine or stavudine plus lamivudine plus nevirapine or efavirenz) for children who met national treatment criteria. MAIN OUTCOME MEASURES: Survival, weight gain, CD4 cell count, and hemoglobin response. RESULTS: After enrollment of 4975 children into HIV care, 2938 (59.1%) started ART. Of those initiating ART, the median age was 81 months (interquartile range, 36-125), 1531 (52.1%) were female, and 2087 (72.4%) with World Health Organization stage information were in stage III or IV. At the time of analysis, 158 children (5.4%) had withdrawn from care and 382 (13.0%) were at least 30 days late for follow-up. Of the remaining 2398 children receiving ART, 198 (8.3%) died over 3018 child-years of follow-up (mortality rate, 6.6 deaths per 100 child-years; 95% confidence interval [CI], 5.7-7.5); of these deaths, 112 (56.6%) occurred within 90 days of therapy initiation (early mortality rate, 17.4/100 child-years; post-90-day mortality rate, 2.9/100 child-years). Mortality was associated with CD4 cell depletion, lower weight-for-age, younger age, and anemia in multivariate analysis. The mean CD4 cell percentage at ART initiation among the 1561 children who had at least 1 repeat measurement was 12.9% (95% CI, 12.5%-13.3%) and increased to 23.7% (95% CI, 23.1%-24.3%) at 6 months, 27.0% (95% CI, 26.3%-27.6%) at 12 months, 28.0% (95% CI, 27.2%-28.8%) at 18 months, and 28.4% (95% CI, 27.4%-29.4%) at 24 months. CONCLUSIONS: Care provided by clinicians such as nurses and clinical officers can result in good outcomes for HIV-infected children in primary health care settings in sub-Saharan Africa. Mortality during the first 90 days of therapy is high, pointing to a need for earlier intervention.Item Monitoring effectiveness of programmes to prevent mother-to-child HIV transmission in lower-income countries.(2008-Jan) Stringer EM; Chi BH; Chintu N; Creek TL; Ekouevi DK; Coetzee D; Tih P; Boulle A; Dabis F; Shaffer N; Wilfert CM; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. eli@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Ambitious goals for paediatric AIDS control have been set by various international bodies, including a 50% reduction in new paediatric infections by 2010. While these goals are clearly appropriate in their scope, the lack of clarity and consensus around how to monitor the effectiveness of programmes to prevent mother-to-child HIV transmission (PMTCT) makes it difficult for policy-makers to mount a coordinated response. In this paper, we develop the case for using population HIV-free child survival as a gold standard metric to measure the effectiveness of PMTCT programmes, and go on to consider multiple study designs and source populations. Finally, we propose a novel community survey-based approach that could be implemented widely throughout the developing world with minor modifications to ongoing Demographic and Health Surveys.Item Single-dose tenofovir and emtricitabine for reduction of viral resistance to non-nucleoside reverse transcriptase inhibitor drugs in women given intrapartum nevirapine for perinatal HIV prevention: an open-label randomised trial.(2007-Nov-17) Chi BH; Sinkala M; Mbewe F; Cantrell RA; Kruse G; Chintu N; Aldrovandi GM; Stringer EM; Kankasa C; Safrit JT; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. bchi@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: Intrapartum and neonatal single-dose nevirapine are essential components of perinatal HIV prevention in resource-constrained settings, but can induce resistance to other non-nucleoside reverse transcriptase inhibitor drugs. We aimed to investigate whether this complication would be reduced with a single peripartum intervention of tenofovir and emtricitabine. METHODS: We randomly assigned 400 HIV-infected pregnant women who sought care at two public-sector primary health facilities in Lusaka, Zambia. One was excluded, 200 were assigned to receive a single oral dose of 300 mg tenofovir disoproxil fumarate with 200 mg emtricitabine under direct observation, and 199 to receive no study drug. Short-course zidovudine and intrapartum nevirapine were offered to all HIV-infected women, according to the local standard of care. Women who met national criteria for antiretroviral therapy were referred for care and not enrolled. Our primary study outcome was resistance to non-nucleoside reverse transcriptase inhibitors at 6 weeks after delivery. We used standard population sequencing to determine HIV genotypes. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00204308. FINDINGS: Of the 200 women who were randomly assigned to the intervention, 14 were lost to follow-up or withdrew from the study, two did not take study drug according to protocol, and one specimen was lost; 23 of 199 controls were lost to follow-up or withdrew from the study, and three specimens were lost. Women given the intervention were 53% less likely than controls to have a mutation that conferred resistance to non-nucleoside reverse transcriptase inhibitors at 6 weeks after delivery (20/173 [12%] vs 41/166 [25%]; risk ratio [RR] 0.47, 95% CI 0.29-0.76). We noted postpartum anaemia, the most common serious adverse event in mothers, in four women in each group. 20 of 198 (10%) infants in the intervention group and 23 of 199 (12%) controls had a serious adverse event, mostly due to septicaemia (n=22) or pneumonia (n=8); these events did not differ between groups, and none were judged to be caused by the study intervention. INTERPRETATION: A single dose of tenofovir and emtricitabine at delivery reduced resistance to non-nucleoside reverse transcriptase inhibitors at 6 weeks after delivery by half; therefore this treatment should be considered as an adjuvant to intrapartum nevirapine.Item Addition of single-dose tenofovir and emtricitabine to intrapartum nevirapine to reduce perinatal HIV transmission.(2008-Jun-01) Chi BH; Chintu N; Cantrell RA; Kankasa C; Kruse G; Mbewe F; Sinkala M; Smith PJ; Stringer EM; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. bchi@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To determine the impact of adjuvant single-dose peripartum tenofovir/emtricitabine (TDF/FTC) on intrapartum/early postpartum HIV transmission. METHODS: In the setting of routine short-course zidovudine (ZDV) and peripartum nevirapine (NVP) for perinatal HIV prevention, participants were randomized to single-dose TDF (300 mg)/FTC (200 mg) or to no intervention in labor. Six-week infant HIV infection was compared according to actual-use drug regimens. RESULTS: Of 397 women randomized, 355 (89%) had infants who were alive and active at 6 weeks postpartum. Of these, 18 (5.1%) were infected in utero and 6 (1.8%) were infected intrapartum/early postpartum. Among the 243 who used ZDV and NVP, intrapartum/early postpartum transmission was not reduced among infants whose mothers received TDF/FTC compared with those who did not (2 of 123 [1.6%] vs. 3 of 109 [2.8%]; P = 0.67). Among the 49 infants whose mothers did not receive antenatal ZDV but who had confirmed NVP ingestion, transmission similarly did not differ (0 of 19 [0%] vs. 1 of 26 [3.4%]). TDF/FTC was not significantly associated with reduced overall transmission (odds ratio [OR] = 0.7, 95% confidence interval [CI]: 0.3 to 1.6), even when other antiretroviral drugs were considered (adjusted OR = 0.8, 95% CI: 0.3 to 1.8). CONCLUSIONS: Adjuvant peripartum single-dose TDF/FTC did not reduce perinatal transmission. Whether a higher dose might be effective remains unknown but should be studied in settings in which NVP is used without antenatal ZDV.Item A pilot study of food supplementation to improve adherence to antiretroviral therapy among food-insecure adults in Lusaka, Zambia.(2008-Oct-01) Cantrell RA; Sinkala M; Megazinni K; Lawson-Marriott S; Washington S; Chi BH; Tambatamba-Chapula B; Levy J; Stringer EM; Mulenga L; Stringer JS; Centre for Infectious Disease Research in Zambia, Plot 1275 Lubutu Road, Lusaka, Zambia. cantrell@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: The provision of food supplementation to food-insecure patients initiating antiretroviral therapy (ART) may improve adherence to medications. METHODS: A home-based adherence support program at 8 government clinics assessed patients for food insecurity. Four clinics provided food supplementation, and 4 acted as controls. The analysis compared adherence (assessed by medication possession ratio), CD4, and weight gain outcomes among food-insecure patients enrolled at the food clinics with those enrolled at the control clinics. RESULTS: Between May 1, 2004, and March 31, 2005, 636 food- insecure adults were enrolled. Food supplementation was associated with better adherence to therapy. Two hundred fifty-eight of 366 (70%) patients in the food group achieved a medication possession ratio of 95% or greater versus 79 of 166 (48%) among controls (relative risk = 1.5; 95% confidence interval: 1.2 to 1.8). This finding was unchanged after adjustment for sex, age, baseline CD4 count, baseline World Health Organization stage, and baseline hemoglobin. We did not observe a significant effect of food supplementation on weight gain or CD4 cell response. CONCLUSIONS: This analysis suggests that providing food to food-insecure patients initiating ART is feasible and may improve adherence to medication. A large randomized study of the clinical benefits of food supplementation to ART patients is urgently needed to inform international policy.Item Causes of morbidity among HIV-infected children on antiretroviral therapy in primary care facilities in Lusaka, Zambia.(2009-Oct) Mubiana-Mbewe M; Bolton-Moore C; Banda Y; Chintu N; Nalubamba-Phiri M; Giganti M; Guffey MB; Sambo P; Stringer EM; Stringer JS; Chi BH; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVES: To describe the pattern of incident illness in children after initiation of antiretroviral therapy (ART) in a large public health sector programme in Lusaka, Zambia. METHODS: Systematic chart review to retrospectively extract data from medical records of children (i.e. <15 years) initiating ART in the Lusaka, Zambia public sector. Incident conditions were listed separately and then grouped according to broad categories. Predictors for incident diagnoses were determined using univariate and multivariable analysis. RESULTS: Between May 2004 and June 2006, 1705 HIV-infected children initiated ART. Of these, 1235 (72%) had their medical records reviewed. Median age at ART initiation was 77 months and 554 (45%) were females. Eight hundred and forty-one (68%) children had an incident condition during this period, with a median time of occurrence of 64 days from ART initiation. Twenty-eight incident conditions were documented. When categorized, the most common were mucocutaneous conditions [incidence rate (IR): 70.6 per 100 child-years, 95% CI: 64.5-77.2] and upper respiratory tract infection (IR: 70.1 per 100 child-years; 95% CI: 64.0-76.7). Children with severe immunosuppression (i.e. CD4 < 10%) were more likely to develop lower respiratory tract infection (16.3%vs. 10.2%; P = 0.003) and mucocutaneous conditions (43.9% vs. 35.3%; P = 0.005) than those with CD4 > or = 10%. CONCLUSION: There is a high incidence of new illness after ART initiation, emphasizing the importance of close monitoring during this period. Early initiation of ART and use of antimicrobial prophylaxis may also help to reduce the occurrence of such co-morbidities.Item Intrapartum tenofovir and emtricitabine reduces low-concentration drug resistance selected by single-dose nevirapine for perinatal HIV prevention.(2009-Nov) Chi BH; Ellis GM; Chintu N; Cantrell RA; Sinkala M; Aldrovandi GM; Warrier R; Mbewe F; Nakamura K; Stringer EM; Frenkel LM; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. bchi@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)A single dose of tenofovir/emtricitabine (TDF/FTC) during labor significantly reduces peripartum nevirapine-associated viral drug resistance when measured by consensus HIV sequencing. It is unknown whether this effect extends to HIV subpopulations of <25-50%. We conducted a randomized trial of single-dose TDF/FTC added to peripartum nevirapine to reduce drug resistance associated with nonnucleoside reverse transcriptase inhibitors (NNRTIs). To detect mutations for NNRTIs comprising > or = 2% of the viral population, we used an oligonucleotide ligation assay (OLA) at codons 103, 106, 181, and 190 of HIV reverse transcriptase. To assess development of drug resistance mutations to our study intervention, OLA was also performed at codons 65 and 184. Among the 328 women included in the 2-week analysis, those receiving TDF/FTC were less likely to have NNRTI resistance by OLA (RR = 0.40, 95% CI = 0.21-0.77). A similar trend was observed among the 315 women included in the 6-week analysis (RR = 0.45, 95% CI = 0.31-0.66). Only two (1%) specimens had detectable K65R by OLA. Both were at 6 weeks postpartum; one was detected in the intervention arm and one in the control arm (p = 0.96). M184V was not detected. The ability of single-dose TDF/FTC to protect against peripartum NVP-induced NNRTI resistance extends to minority populations. This efficacy is achieved without significant selection of TDF- or FTC-resistant viruses.