Fig. 2

Samples collected on maternal and newborn participants. a. Maternal samples included: (1) blood, including 10 mLs in EDTA tubes for plasma, peripheral blood mononuclear cell (PBMC) isolation, and granulocyte or neutrophil isolation; 5–7.5 mL in serum separator tube for serum; 2.5 mL in PaxGene tube for RNA; (2) saliva and/or (3) sputum (sputum if patient had productive cough); (4) nasal swab; (5) oropharyngeal swab; (6) maternal and fetal side placental biopsies for RNA extraction, and formalin-fixed paraffin-embedded full thickness placental block for in situ placental histopathology; (7) umbilical cord blood (EDTA, serum separator tube and PaxGene as described above for maternal blood); (8) colostrum or mature breastmilk; (9) vaginal swab; (10) rectal swab; (11) urine; (12) stool. Maternal blood was preferentially collected during a clinical blood draw by the clinical nurse. Placental biopsies and cord blood were collected by the obstetrical care team immediately after delivery, with support from study staff when possible. Women who planned to breastfeed were encouraged to clean the breast per instructions and self-collect any amount of colostrum or mature milk prior to discharge from the hospital. b. Newborn samples included: (1) nasopharyngeal swab; (2) oropharyngeal swab; (3) tracheal aspirate (if relevant); (4) neonatal blood collected into EDTA microtainer via heel-stick with clinical metabolic screen at 24–36 h of life; (5) urine collected using cotton balls placed into diaper; and (6) stool. Figure created with BioRender.com and reproduced with permission