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Shifting dynamics of HIV transmission timing among infants in the era of option B+ and implications for infant testing
Abstract Content:
Background: Universal
antiretroviral treatment(ART) for HIV-positive pregnant women is anticipated
to significantly reduce mother-to-child HIV transmission (MTCT). The World
Health Organization recommends infant HIV testing at 4-6 weeks to capture in-utero/intrapartum/early breastfeeding
transmission. In-utero infection is
associated with high mortality of 20-30% by age 8-12 weeks. We conducted an implementation research study
to determine the relative yield of HIV birth testing.
Methods: HIV-positive and negative pregnant women were enrolled in an observational cohort to evaluate effectiveness of universal maternal ART within 13 health facilities in Lesotho following introduction of Option B+. HIV birth testing (DNA PCR within two weeks of birth) was introduced at study sites in addition to routine six-week infant testing, per national guidelines. Dried blood spots were collected at birth for PCR testing (Roche CAP/CTM HIV v2) followed by routine six-week testing. Data were analyzed to identify HIV transmission rates at birth and six weeks.
Results: Among 602 women (median age, 29 years; median gestational age at first ANC visit, 24 weeks), 427/602 (70%) of their infants were tested at birth, 497/602 (83%) were tested at 6 weeks, and 363/422 (86%) of infants uninfected at birth were retested at 6 weeks. In utero HIV infection with positive birth PCR occurred in 5/427 (1.2%) infants. An additional 2 infants, one with a prior negative birth test and a second without a prior birth test tested positive at 6 weeks, for a cumulative MTCT incidence of 1.25% (95%CI: 0.5%-2.6%). The 6-week MTCT rate was 1/211 (0.5%) among women who initiated ART before pregnancy compared to 6/331 (1.8%) among women who started ART during pregnancy. Maternal HIV RNA levels were associated with transmission: median HIV RNA was 1.27 log10 copies/mL among non-transmitting women versus 5.03 log10 copies/mL among transmitting women.
Conclusions: Universal antenatal maternal ART resulted in very low 6-week MTCT (< 1.5%); MTCT rates were lowest with pre-pregnancy ART initiation. Among infants, in contrast to pre-ART era, where ~30% of infections occurred in utero, most infections (5/7, 71%) were identified at birth, suggesting that introduction of birth testing, if accompanied by rapid infant ART initiation, could significantly impact the health of infected infants.
Methods: HIV-positive and negative pregnant women were enrolled in an observational cohort to evaluate effectiveness of universal maternal ART within 13 health facilities in Lesotho following introduction of Option B+. HIV birth testing (DNA PCR within two weeks of birth) was introduced at study sites in addition to routine six-week infant testing, per national guidelines. Dried blood spots were collected at birth for PCR testing (Roche CAP/CTM HIV v2) followed by routine six-week testing. Data were analyzed to identify HIV transmission rates at birth and six weeks.
Results: Among 602 women (median age, 29 years; median gestational age at first ANC visit, 24 weeks), 427/602 (70%) of their infants were tested at birth, 497/602 (83%) were tested at 6 weeks, and 363/422 (86%) of infants uninfected at birth were retested at 6 weeks. In utero HIV infection with positive birth PCR occurred in 5/427 (1.2%) infants. An additional 2 infants, one with a prior negative birth test and a second without a prior birth test tested positive at 6 weeks, for a cumulative MTCT incidence of 1.25% (95%CI: 0.5%-2.6%). The 6-week MTCT rate was 1/211 (0.5%) among women who initiated ART before pregnancy compared to 6/331 (1.8%) among women who started ART during pregnancy. Maternal HIV RNA levels were associated with transmission: median HIV RNA was 1.27 log10 copies/mL among non-transmitting women versus 5.03 log10 copies/mL among transmitting women.
Conclusions: Universal antenatal maternal ART resulted in very low 6-week MTCT (< 1.5%); MTCT rates were lowest with pre-pregnancy ART initiation. Among infants, in contrast to pre-ART era, where ~30% of infections occurred in utero, most infections (5/7, 71%) were identified at birth, suggesting that introduction of birth testing, if accompanied by rapid infant ART initiation, could significantly impact the health of infected infants.