SaniVac Trial - Sanitation and Oral Rotavirus Vaccine Performance

This is a controlled cohort study to assess the effect of improved sanitation on oral rotavirus vaccine performance in low-income urban neighbourhoods of Maputo, Mozambique. The specific hypotheses are that: (1) access to improved sanitation is associated with increased oral rotavirus vaccine immunogenicity; (2) enteric infection concurrent to oral rotavirus vaccination is associated with reduced oral rotavirus vaccine immunogenicity; and (3) Environmental Enteric Dysfunction is associated with reduced oral rotavirus vaccine immunogenicity.

Pregnant women will be enrolled from the intervention and control arms of a previous sanitation trial (NCT02362932) post-intervention and will be enrolled at no later than eight months' gestation and then followed to 4 months of age of the infant. Blood samples and faeces will be taken from the infant at the time of administration of the first dose of the oral rotavirus vaccine and four weeks after the second dose of the vaccine.

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.