UBC Theses and Dissertations
The pattern and pathways of infectious morbidity in South African HIV exposed uninfected infants Slogrove, Amy L.
Background: Universal infant morbidity risk factors (poor birth outcomes, suboptimal breastfeeding, poverty) occur more frequently in HIV exposed uninfected (HEU) than HIV unexposed uninfected (HUU) infants. HEU infants’ unique exposures, including in utero exposure to HIV products and maternal immune compromise, may potentiate HEU infants’ infectious morbidity risk. The primary objective was to determine whether HEU infants experience greater infectious morbidity than HUU infants through HIV exposure-specific pathways beyond universal infant morbidity risk factors. Methods: This prospective cohort study identified low risk HIV-infected and HIV-uninfected mothers and their term newborns from a single community midwife unit in Kraaifontein, South Africa. The primary outcome, at least one infectious cause hospitalization or death before six months of age, was classified according to modified WHO case-definitions and compared between HEU and HUU infants. Complete outcome determination on all infants was possible through linkage with the electronic provincial hospital administration system and mortality registry. Adjusted odds ratios (aOR) were calculated by multivariable logistic regression including stratified analyses conditioned on breastfeeding. Results: One hundred and seventy six (94 HEU, 82 HUU) mother-infant pairs were included. HIV-infected mothers were older (median 27.8 vs. 24.7 years, p<0.01) and HEU infants less often breastfed (35/94 (37%) vs. 81/82 (99%), p<0.001). The groups were similar on maternal education, antenatal course, household characteristics, birth weight, gestational age and immunizations. Incidence rate ratio of all-cause sick clinic visits in HEU compared to HUU infants was 0.82 (95% CI 0.58,1.16). The primary outcome occurred in 17 (18%) HEU and 10 (12%) HUU infants (p=0.38), giving an aOR of 1.45 (95% CI 0.44,4.55). In stratified analysis comparing only infants with any breastfeeding, HEU infants had an aOR for a very severe infectious cause hospitalization or death of 4.2 (95% CI 1.00,19.2, p=0.05). Seven of 17(41%) HEU and 1/10 (10%) HUU primary outcome events occurred after 90 days of age (p=0.07). Conclusion: Amongst term infants with similar social circumstances, a higher probability of very severe infectious morbidity was observed in breastfed HEU compared to breastfed HUU infants. HEU infant risk may be driven through HIV exposure-specific pathways unrelated to universal infant morbidity risk factors.
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