Study of Remdesivir in Participants Below 18 Years Old With COVID-19

Pediatric participants will be enrolled as follows: Pediatric participants ≥ 28 days to \< 18 years old: * Cohort 1: ≥ 12 years to \< 18 years and weight ≥ 40 kg * Cohort 2: ≥ 28 days to \< 18 years and weight ≥ 20 kg to \< 40 kg * Cohort 3: ≥ 28 days to \< 18 years and weight ≥ 12 kg to \< 20 kg * Cohort 4: ≥ 28 days to \< 18 years and weight ≥ 3 kg to \< 12 kg * Cohort 8: \< 12 years and weight ≥ 40 kg Term neonatal participants 0 days to \< 28 days old: * Cohort 5: ≥ 14 days to \< 28 days of age, gestational age \> 37 weeks and weight at screening ≥ 2.5 kg * Cohort 6: 0 days to \< 14 days of age, gestational age \> 37 weeks and birth weight ≥ 2.5 kg Preterm neonates and infants 0 days to \< 56 days old: * Cohort 7: 0 days to \< 56 days of age, gestational age ≤ 37 weeks and birth weight ≥ 1.5 kg