The primary outcome of interest in the study is oral rotavirus vaccine immunogenicity among participating vaccinated infants. Seroconversion is defined as a ≥ fourfold rise in serum anti-rotavirus IgA titers between first dose of oral RV vaccine and 4 weeks (+/- 1 week) after second dose of oral RV vaccine. Enteric infections are defined as the presence of ≥ 1 of the following enteric infections in stool: adenovirus 40/41, rotavirus A, norovirus GI/GII, Salmonella spp. (including serovars Typhi and Paratyphi), Campylobacter spp. (C. jejuni, C. coli, C. lari), Shigella spp. (S. boydii, S. sonnei, S. flexneri, S. dysenteriae), Clostridium difficile Toxin A/B, enterotoxigenic Escherichia coli (ETEC) LT/ST, E. coli O157, Shiga-like toxin-producing E. coli (STEC) stx1/stx2, Yersinia enterocolitica, Vibrio cholerae, Giardia lamblia, Entamoeba histolytica, and Cryptosporidium spp. (C. parvum, C. hominis). Environmental Enteric Dysfunction is measured via a combined disease activity score including faecal markers of intestinal inflammation and permeability: neopterin, α-1 antitrypsin, and myeloperoxidase in stool.