; all were HBGA secretors or partial secretors. This is the first epidemiological study demonstrating in a population that HBGA phenotype is a key susceptibility factor for both norovirus and rotavirus infections in children.

Male couple Anti-HBc positivity 7.15 (5.09-10.03) 0.000 Sex during menstruation 0.75 (0.59-0.96) 0.013 Male couple history of sex with other men 5.49 (2.38-12.64) 0.000 Being younger than 19 years 0.54 (0.40-0.72) 0.000 Sexual initiation before age 15 years 1.32 (1.05-1.66) 0.008 Male couple with more than 10 sex partners lifetime 1.94 (1.36-2.76) 0.000 Male couple with at least 1 more sex partner in last 12 months 1.65 (1.22-2.23) 0.000 Male couple with more than 20 sex partners lifetime 1.90 (1.22-2.96) 0.002