Maternal and Breastmilk Viral Load: Impacts of Adherence on Peripartum HIV Infections Averted—The Breastfeeding, Antiretrovirals, and Nutrition Study

Abstract

Background Antiretroviral interventions are used to reduce HIV viral replication and prevent mother-to-child transmission. Viral suppression relies on adherence to antiretrovirals. Methods A two-phase study was conducted using data from the Breastfeeding, Antiretrovirals and Nutrition study. We included mothers randomized to 28 weeks of postpartum antiretrovirals with ≥1 plasma or breastmilk specimen. All mothers who transmitted HIV to their infants from 2-28 weeks (n=31) and 15% of mothers who did not (n=232) were included. Adherence was measured by pill count [categorized as poor (0-80%), partial (81-98%) and near perfect (>98%)]. Associations between adherence and breastmilk RNA were assessed using mixed effects models. Cox models were used to estimate associations between breastmilk RNA and HIV transmission. Using Monte Carlo simulation, we estimated the number of transmissions that would occur had everyone randomized to maternal ARVs been 90% and 100% adherent. Results Partial or near perfect antiretroviral adherence significantly reduced the odds of having detectable (≥40 copies/ml) breastmilk RNA, compared to poor adherence (OR 0.23, 95% CI 0.08-0.67; OR 0.36, 95% CI 0.16-0.81, respectively). Detectable breastmilk RNA was associated with increased breastmilk transmission, compared to undetectable breastmilk RNA (HR 3.8, 95% CI 1.2-12.1). All transmitting mothers had ≥1 plasma viral load specimen >100 copies/ml. An estimated similar number of transmissions would occur with 90% adherence compared with 100%. Conclusions Helping patients adhere to antiretrovirals throughout breastfeeding is important for realizing the full potential of recommended antiretroviral interventions to prevent mother-to-child HIV transmission. Maintaining plasma viral load <100 copies/ml may prevent breastmilk transmission.

Level and determinants of postpartum adherence to antiretroviral therapy in the Eastern Cape, South Africa

“…ART has reduced in-utero transmission to less than 1%, but many babies are still getting infected during the postpartum period. Optimal and sustained (complete) adherence to ART is required for virological suppression, elimination of mother-to-child transmission of HIV, averting new horizontal HIV transmission, and preventing drug resistance and AIDS-related deaths [4,5].…”

Moving closer to what women want? A review of breastfeeding and women living with HIV in the UK and high‐income countries

“…At an individual level, the risk of HIV transmission through breastfeeding varies depending on maternal and infant factors. The risk of postnatal vertical transmission increases with reduced adherence to ART and the associated rise in levels of maternal HIV RNA in breastmilk . However, maternal plasma viral load does not perfectly correlate with that of breastmilk, and breastmilk viral load is variable over time and between each breast .…”

“…The risk of postnatal vertical transmission increases with reduced adherence to ART and the associated rise in levels of maternal HIV RNA in breastmilk . However, maternal plasma viral load does not perfectly correlate with that of breastmilk, and breastmilk viral load is variable over time and between each breast . There is evidence that postnatal vertical transmission can occur even when the mother has an undetectable plasma viral load .…”

“…Table 2 Ten safer breastfeeding rules 1 Tell your HIV team if you want to breastfeedit may not be as safe as formula feeding, but they will help you make it as safe as possible for your baby [1012]. 2 100% adherence to ART drugs [16,17]. 3 Stop all breastfeeding as early as possible [10,15,47].…”

“…Do not breastfeed if you or your baby develops diarrhoea or vomiting [17]. 8 Only breastfeed when you have an undetectable viral load [13,16,17]. 9…”