The Protective Effects of Goishi Tea Against Influenza Infection

Goishi tea is a Japanese traditional post-fermented tea that is only manufactured in Otoyo town, Kochi prefecture by a unique method. A previous study has reported the in vitro inhibitory effects of Goishi tea against H1N1 and H3N2 influenza infections. The present study was aimed to evaluate its clinical protective efficacy for children against the virus during the H1N1 2009 influenza pandemic and seasonal influenza in 2010 and 2011. Students at Otoyocho Junior High School were given Goishi tea during each outbreaks. The result of the clinical test for three years showed that the infection risk doubled, when there was no-intake of Goishi tea(odds ratio 2.0, 95%confidential interval 1.1-3.8, P=0.02). This finding indicated that Goishi tea is likely to prevent influenza infection by delaying the infection in humans.