Severe acute respiratory syndrome coronavirus 2 prevalence in saliva and gastric and intestinal fluid in patients undergoing gastrointestinal endoscopy in coronavirus disease 2019 endemic areas: Prospective cross-sectional study in Japan. - Miyake S; Ashikari K; Kato S; Takatsu T; Kuwashima H; Kaneko H; Nagai K; Watari I; Sato T; Yamaoka Y; Yamamoto T; Ryo A; et al. (Digestive endoscopy : official journal of the Japan Gastroenterological Endoscopy Society, 2022)