Timing of mother-to-child transmission of HIV-1 and infant mortality in the first 6 months of life in Harare, Zimbabwe

Zijenah, Lynn S.; Moulton, Lawrence H.; Iliff, Peter; Nathoo, Kusum; Munjoma, Marshall; Mutasa, Kuda; Malaba, Lucie C.; Zvandasara, Parteson; Ward, Brian J.; Humphrey, Jean H.

doi:10.1097/00002030-200401230-00017

Cited by 70 publications

(56 citation statements)

References 28 publications

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“…First, a strong concentration of women of peak child- *Weighted average of HIV prevalence at baseline and two rounds of follow-up. HIV prevalence in children estimated from prevalence in pregnant women in the study communities, data on vertical transmission in Zimbabwe (37), and data on postinfection childhood survival (38). † Based on fertility and mortality among uninfected individuals.…”

Section: Discussion Empirical Evidence: Summary and Consistency With mentioning

confidence: 99%

“…These periods were calculated for each inter-survey period from data on dates of initial and follow-up household interview and dates of migration into/from household and/or death, where appropriate, and were then aggregated. For infant and early childhood mortality rates, we used indirect estimates derived from data on HIV prevalence in pregnant women (pregnant in the inter-survey periods) collected in the socioeconomic stratum, an estimate of 30.7% for the probability of vertical transmission of HIV infection in Zimbabwe (37), and estimates for age-specific mortality from 0-1 years ( 1 m 0 ) and 1-4 years ( 4 m 1 ) of 0.429 and 0.132 for HIV-infected infants (38) and 0.056 and 0.007 for uninfected infants in sub-Saharan African populations. We assumed that no AIDS deaths occurred in the other age intervals not covered in the individual cohort and estimated non-AIDS mortality for these ages using data from the longitudinal household census adjusted for underreporting (25).…”

Section: Methodsmentioning

confidence: 99%

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Critique of early models of the demographic impact of HIV/AIDS in sub-Saharan Africa based on contemporary empirical data from Zimbabwe

Gregson

Nyamukapa

Lopman

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Early mathematical models varied in their predictions of the impact of HIV/AIDS on population growth from minimal impact to reductions in growth, in pessimistic scenarios, from positive to negative values over a period of 25 years. Models predicting negative rates of natural increase forecast little effect on the dependency ratio. Twenty years later, HIV prevalence in small towns, estates, and rural villages in eastern Zimbabwe, has peaked within the intermediate range predicted by the early models, but the demographic impact has been more acute than was predicted. Despite concurrent declines in fertility, fueled in part by HIV infections (total fertility is now 8% lower than expected without an epidemic), and a doubling of the crude death rate because of HIV/AIDS, the rate of natural population increase between 1998 and 2005 remained positive in each socioeconomic stratum. In the worst-affected areas (towns with HIV prevalence of 33%), HIV/AIDS reduced growth by two-thirds from 2.9% to 1.0%. The dependency ratio fell from 1.21 at the onset of the HIV epidemic to 0.78, the impact of HIVassociated adult mortality being outweighed by fertility decline. With the benefit of hindsight, the more pessimistic early models overestimated the demographic impact of HIV epidemics by overextrapolating initial HIV growth rates or not allowing for heterogeneity in key parameters such as transmissibility and sexual risk behavior. Data collected since the late 1980s show that there was a mismatch between the observed growth in the HIV epidemic and assumptions made about viral transmission.dependency ratio ͉ population growth T he initial observation of a growing AIDS epidemic among heterosexual populations in the Americas and Africa generated concern over the eventual scale and impact of the pandemic. A range of models was developed to explore the future spread of infection and its impact on mortality based on the available pattern of growth in HIV prevalence, patterns of sexual behavior, transmissibility of the virus, and progression from infection to AIDS and death. Initial predictions, based on the early growth of the epidemic and a long duration of infectiousness, predicted that, over a period of decades, HIV could well turn population growth rates negative (1, 2). However, others disagreed (3), and the consensus at a United Nations and World Heath Organization workshop held in December 1989 was that the epidemic could have an important effect on population growth but that negative rates of natural increase were unlikely (4). A maximum reduction of 30% in the growth rate over a period of Ͻ50 years was predicted. The relationship between mortality in young adults and decreased births meant that, even in models with an extreme impact, dependency ratios were predicted to remain unchanged (1, 2).Over time, our understanding of the spread of HIV and its impact on fertility and mortality has improved and has been included in more recent models (5-7). Model predictions can be compared with empirical estimates of demographic impact o...

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Section: Discussion Empirical Evidence: Summary and Consistency With mentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Critique of early models of the demographic impact of HIV/AIDS in sub-Saharan Africa based on contemporary empirical data from Zimbabwe

Gregson

Nyamukapa

Lopman

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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show abstract

“…These findings do not encourage the daily administration of vitamin A and beta-carotene to HIV-infected women during pregnancy or lactation. The effects of a single mega dose administered during the early postpartum, as suggested from studies of HIV-uninfected women (Stoltzfus et al, 1993;Roy et al, 1997;Rice et al, 1999;Bahl et al, 2002), are currently being assessed in a randomized clinical trial among HIV-infected women (Zijenah et al, 2004). Direct Effect of vitamin supplementation to HIV-infected pregnant womensupplementation to neonates is one alternative that has proven effective in decreasing child mortality (Humphrey et al, 1996;Rahmathullah et al, 2003); however, it is not known whether vitamin A supplementation to HIV-uninfected infants born to HIV-infected mothers could increase their risk of becoming infected.…”

Section: Discussionmentioning

confidence: 99%

Effect of vitamin supplementation to HIV-infected pregnant women on the micronutrient status of their infants

et al. 2005

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Objective: We examined whether supplementation with vitamin A and/or vitamins B, C, and E to HIV-infected women during pregnancy and lactation is related to increased concentrations of vitamins A, B12, and E in their infants during the first 6 months of life. Design: We carried out a randomized clinical trial among 716 mother-infant pairs in Dar-es-Salaam, Tanzania. Women were randomly allocated to receive a daily oral dose of one of four regimens: vitamin A, multivitamins (B, C, and E), multivitamins including A, or placebo. Supplementation started at first prenatal visit and continued after delivery throughout the breastfeeding period. The serum concentration of vitamins A, E and B12 was measured in infants at 6 weeks and 6 months postpartum. Results: Maternal vitamin A supplementation increased serum retinol in the infants at 6 weeks (mean difference ¼ 0.09 mmol/l, Po0.0001) and 6 months (mean difference ¼ 0.06 mmol/l, P ¼ 0.0002), and decreased the prevalence of vitamin A deficiency, but had no impact on serum vitamins E or B12. Multivitamins increased serum vitamin B12 at 6 weeks and 6 months (mean differences ¼ 176 pmol/l, Po0.0001 and 127 pmol/l, Po0.0001, respectively) and vitamin E (mean differences ¼ 1.8 mmol/l, P ¼ 0.0008 and 1.1 mmol/l, P ¼ 0.004, respectively) and decreased the prevalence of vitamin B12 deficiency. Conclusions: Vitamin supplementation to HIV-1-infected women is effective in improving the vitamin status of infants during the first 6 months of age.

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“…Low arm circumference has been validated in epidemiological studies and emergency situations as an indicator of acute wasting (James et al, 1994) and, among HIV-infected African women, it has been identified as an independent predictor of mortality (Lindan et al, 1992) and early MTCT (Zijenah et al, 2004). In a study in Zimbabwe, the mean difference in MUAC between mothers who transmitted HIV to their babies and those who did not was about 9 mm (Zijenah et al, 2004), whereas, we found an average negative zinc effect of 4 mm, limited to the second trimester. Whether this decline is clinically relevant as a predictor of mortality or MTCT is yet to be determined.…”

Section: Zinc Supplements Among Hiv-infected Women E Villamor Et Almentioning

confidence: 99%

Zinc supplementation to HIV-1-infected pregnant women: Effects on maternal anthropometry, viral load, and early mother-to-child transmission

et al. 2006

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Objective: To examine the effect of zinc supplementation to HIV-1-infected pregnant women on viral load, early mother-tochild transmission of HIV (MTCT), and wasting. Design: Double-blind placebo-controlled randomized clinical trial. Setting: Antenatal clinic in Dar es Salaam, Tanzania. Subjects: Four hundred HIV-1-infected pregnant women. Methods: Women 12-27 weeks of gestation were randomly assigned to receive a daily oral dose of 25 mg zinc or placebo from the day of the first prenatal visit until 6 weeks postdelivery. Weight and mid-upper arm circumference (MUAC) were measured monthly. HIV status of the babies was assessed at birth and at 6 weeks postpartum. Viral load was assessed in a random sample of 100 women at baseline and at the end of the study. Results: Zinc had no effects on maternal viral load or early MTCT. Supplementation was related to a significant threefold increase in the risk of wasting (reaching a MUAC value o22 cm) during an average 22 weeks of observation (RR ¼ 2.7, 95%CI ¼ 1.1, 6.4, P ¼ 0.03), and to a 4 mm decline in MUAC during the second trimester (P ¼ 0.02). Conclusions: Zinc supplementation to HIV-infected pregnant women offers no benefits on viral load or MTCT. The clinical relevance of an apparent decrease in MUAC associated with zinc supplementation is yet to be ascertained. These findings together with the lack of effect on fetal outcomes (reported previously) do not provide support for the addition of zinc supplements to the standard of prenatal care among HIV-infected women.

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Timing of mother-to-child transmission of HIV-1 and infant mortality in the first 6 months of life in Harare, Zimbabwe

Cited by 70 publications

References 28 publications

Critique of early models of the demographic impact of HIV/AIDS in sub-Saharan Africa based on contemporary empirical data from Zimbabwe

Critique of early models of the demographic impact of HIV/AIDS in sub-Saharan Africa based on contemporary empirical data from Zimbabwe

Effect of vitamin supplementation to HIV-infected pregnant women on the micronutrient status of their infants

Zinc supplementation to HIV-1-infected pregnant women: Effects on maternal anthropometry, viral load, and early mother-to-child transmission

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