Study visits
Breast milk, breast milk
ADVERSE EVENTS, BLOOD, BLOOD SPOTS
Enrolment, study intervention, follow-up (Sample collection summary*Window for visit 2, or birth visit: 0–14 days; visit 3 or 4-month visit: 3.5–6 months; visit 4 or 12-month visit: 11–18 months. Venous blood is collected by heel or finger prick onto Guthrie cards. Cord blood collected by midwives is split into three ways: spotted onto a Guthrie card; into a paediatric heparinised blood tube (for plasma) and into tubes containing media to be used for immunology studies. An aliquot of cord blood in media is used immediately for immune phenotyping then cord blood mononuclear cells are isolated from the remainder and stored within 24 hours for future batched challenge assays. Cord and venous plasma are stored for batched measurement of vitamin D levels (where volume allows), immune markers, vaccine antibodies. Blood spots (Guthrie cards) are used exclusively for measurement of vitamin D levels. Breast milk (collected at least 3 days post partum to avoid colostrum), saliva and nasal swabs (collected into skim milk, tryptone, glucose and glycerol media) are stored immediately until required for outcome analysis. All samples (apart from blood spots) are stored at −80°C.Visit 0, screening: Families are approached during antenatal appointments (20Visit 1, enrolment: Pregnant mothers are eligible for enrolment at 28Visit 2, birth: At delivery, cord blood is collected by the attending obstetricians or midwives and transported to the laboratory for processing within 24 hours. Study staff visit mothers and their babies within 14 days of birth. The visit coincides with the end of the maternal supplementation. Blood and breast milk (at least 3 days post partum) are collected from mothers. Blood and saliva are collected from neonates. Infant study medicine is commenced, and the first dose is administered.Visit 3, infant age 4 months: Families are visited when infants are 3.5–6 months of age, coinciding with the end of the infant supplementation period (16th week post partum). An infant blood, nasal swab and saliva sample are collected.Visit 4, infant age 12 months: The final study visit occurs between infant ages 11–18 months. An infant blood and nasal swab are collected. Families receive a small thankyou gift for their contribution.Routine data are collected at each visit, including personal, household and community demographics, medical and vaccination history, smoke exposure, time spent indoors and use of vitamin D or other supplements, breastfeeding status and infant growth metrics. Serious adverse events (SAEs) and clinical outcomes are monitored via maternal and infant medical records (hospital and primary care) throughout follow-up.