“…All 21 studies implemented at least one intervention of a promotional program with educational sessions or informative content and reminders. The educational sessions were characterized by education of the target group through either verbally communicated hand and respiratory hygiene lessons (e.g., instructions by telephone, on the internet, or face-to-face), with training or instructions on how and how frequent to practice hand hygiene and to use face masks or in combination with written or visual media (e.g., information leaflets, posters, video/live demonstration) ( 7 , 9 , 15 , 17 – 20 , 31 ). In addition to that, some studies consisted of the provision of hand hygiene materials, either soap ( 14 , 19 ), alcohol-based hand sanitizers ( 14 , 15 , 18 – 20 , 31 ), face masks ( 14 , 19 , 20 ), provided by the researchers to every participating individual ( 14 , 19 , 20 ) or to be shared within their cluster or with others in case of provision at a common place (e.g., common courtyards or school toilets) ( 15 , 18 , 31 ).…”