Botswana tests for in utero and intrapartum mother-to-child HIV transmission (MTCT) by infant HIV PCR at age 6 weeks. Limitations to this strategy include early mortality, loss-to-follow-up, and delayed treatment initiation for infected infants. In 2015, the Botswana-Harvard Partnership launched the Early Infant Treatment Study to identify HIV-infected infants at birth and offer immediate antiretroviral therapy. To determine the feasibility of targeted birth testing for infants at high-risk of HIV infection, we evaluated risk factors for in utero MTCT that were identifiable at delivery.
HIV-exposed infants were screened at 5 hospital maternity wards by trained research assistants in the Gaborone and Francistown regions of Botswana. Screened infants met the following inclusion criteria: mother/guardian ≥ 18 years of age, gestational age at birth ≥ 35 weeks, birth weight ≥ 2000 grams, age < 96 hours, and eligible for antiretroviral treatment (ART) through the Botswana government program. Consenting mothers were assessed for MTCT risk factors by their obstetric card or verbally. Risk factors included < 8 weeks ART in pregnancy, last CD4 known to be <250 cells/mm³, last HIV RNA known to be > 400 copies/mL, poor maternal ART adherence, lack of maternal zidovudine in labor, or lack of infant post-exposure prophylaxis. Infants underwent heel stick and 3-5 dried blood spots were collected for testing by Roche Cobas Ampliprep/Cobas Taqman HIV-1 qualitative PCR.
In the first year of the study (April 2015 to April 2016), 4086 HIV-exposed infants were delivered at the screening maternities, of whom 3541 (87%) had not been discharged, 2580 (63%) were eligible, and 2303 (56%) agreed to be screened for HIV. Of the 2303 infants screened, 369 (16%) were identified as high-risk for HIV infection. In total, 12 (0.5%) of the 2303 infants were identified as HIV positive at birth. All 12 positive infants were identified as high risk at the time of screening, and all were identifiable as high risk by either < 8 weeks of maternal ART in pregnancy (75%) or lack of maternal HIV suppression at last test (25%) (Table 1).
In utero MTCT occurred only among infants identified as high risk at the time of delivery, using information available from the mother or her obstetric record. Birth testing that targets high risk infants is likely to identify the large majority of in utero HIV transmissions, and allows early ART initiation for these infants.