Clinical and Translational Report Effect of Antibiotic-Mediated Microbiome Modulation on Rotavirus Vaccine Immunogenicity: A Human, Randomized-Control Proof-of-Concept Trial Graphical Abstract Highlights d Rotavirus vaccine immunogenicity tested following antibiotic administration in adults d Antibiotics did not alter absolute anti-RV IgA titers d Narrow-spectrum antibiotics increased anti-RV IgA boosting and RV shedding by day 7 d Microbiome composition correlates with RVV boosting and shedding Authors Vanessa C. Harris, Bastiaan W. Haak, Scott A. Handley, ..., Ester M.M. van Leeuwen, Michael Boele van Hensbroek, Willem Joost Wiersinga Correspondence v.c.harris@amc.nl In Brief Rotavirus vaccines (RVV) are less effective in poor-resourced settings. This randomized-controlled trial in adults tested the effect of microbiome modulation via broad-spectrum, narrow- spectrum, or no antibiotics on RVV performance. Absolute anti-RV IgA titer did not change. However, antibiotics resulted in higher day-7 boosting and increased RV-antigen shedding. Harris et al., 2018, Cell Host & Microbe 24, 197–207 August 8, 2018 ª 2018 Elsevier Inc. https://doi.org/10.1016/j.chom.2018.07.005