Has hand washing as a means to reduce disease transmission ever been studied outside of third world countries? I tried to look it up once and the only studies I

Has hand washing as a means to reduce disease transmission ever been studied outside of third world countries? I tried to look it up once and the only studies I could find were all in cultures that used their bare hands to clean themselves after defecating. At that point, it seems kind of obvious that washing your hands reduces disease. But for cultures that have more "advanced" bathroom ritual, is hand washing beyond cleaning literal shit off your hands actually effective? I can't imagine that a person could dedicate enough time to hand washing versus the amount of times they touch things and their faces, to make it a practice with good enough adherence rates to be considered useful policy.