Patient description: The patient is a 3-day-old female infant with jaundice that started one day ago. She was born at 34w of gestation and kept in an incubator due to her gestational age. Vital signs were reported as: axillary temperature: 36.3°C, heart rate: 154 beats/min, respiratory rate: 37 breaths/min, and blood pressure: 65/33 mm Hg. Her weight is 2.1 kg, length is 45 cm, and head circumference 32 cm. She presents with yellow sclera and icteric body. Her liver and spleen are normal to palpation. Laboratory results are as follows: Serum total bilirubin: 21.02 mg/dL Direct bilirubin of 2.04 mg/dL AST: 37 U/L ALT: 20 U/L GGT: 745 U/L Alkaline phosphatase: 531 U/L Creatinine: 0.3 mg/dL Urea: 29 mg/dL Na: 147 mEq/L K: 4.5 mEq/L CRP: 3 mg/L Complete blood cell count within the normal range. She is diagnosed with neonatal jaundice that may require phototherapy.

Clinical trial eligibility criteria: eligible ages (years): 0.0-0.008,  HIV Infections Mother was of legal age to provide independent informed consent for research participation and was willing and able to provide written informed consent for her and her infant's participation in this study Mother had confirmed HIV-1 infection based on testing of two samples collected at different time points. More information on this criterion can be found in the protocol At entry, infant met EFV exposure requirements, based on mother's report and confirmed by medical records if available, as follows For Cohort 1, Stratum 1A: Infant born to a mother who did not receive EFV during the eight weeks immediately prior to delivery. Note: Breastfeeding and formula feeding infants were eligible for this stratum For Cohort 1, Stratum 1B: Infant born to a mother who received EFV for a minimum of two weeks immediately prior to delivery. Note: Breastfeeding and formula feeding infants were eligible for this stratum For Cohort 2, Stratum 2A: Infants born to a mother who did not receive EFV during the eight weeks immediately prior to delivery and if breastfeeding, mother was not receiving maternal EFV. Note: Breastfeeding and formula feeding infants were eligible for this stratum For Cohort 2, Stratum 2B: Breastfeeding infants born to a mother who received EFV for a minimum of two weeks immediately prior to delivery, intended to breastfeed for a minimum of six weeks and continued to receive maternal EFV while breastfeeding. Note: Only breastfeeding infants were eligible for this stratum At birth, infant's estimated gestational age was at least 37 weeks. Note: If gestational age at birth is not documented in the infant's available birth records, study staff may assess gestational age at the earliest possible opportunity during the screening period and use this assessment for purposes of determination At birth, infant's weight was at least 2 kg. Note: If weight at birth is not documented in the infant's available birth records, study staff may assess infant weight at the earliest possible opportunity during the screening period and use this assessment for purposes of determination At entry, infant was less than or equal to 3 days old  Infant had any other condition that, in the opinion of the site investigator or designee, would make participation in the study unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving the study objectives; for example, severe congenital malformation, other medical condition, or clinically significant finding from physical examination At entry, any positive infant HIV nucleic acid test result (results are not required to be available prior to entry but any positive results obtained prior to entry are exclusionary) At entry, infant or breastfeeding mother was receiving any disallowed medication listed in the protocol Mother received maraviroc during pregnancy