Effects of a Kneipp-Based Kindergarten Program on Sick Days: A Cluster-Randomized Mixed-Methods Study

Purpose: This study evaluated the effects of the holistic Kneipp Concept (KC) on sick days and experience with Kneipp kindergarten activities, aimed to address seasonal infections. Methods: A confirmatory, mixed-method, cluster-randomized controlled trial with an open waitlist design was conducted (October 2023–September 2024, DRKS-Registry-ID: DRKS00029275). Socio-demographically clustered Kindergartens in-and-around Berlin were randomized into KC Immediate (IG) or waitlist (WL) groups. Kindergarten directors, teachers, and parents of children (ages 2–6) participated. The intervention involved KC’s five elements, emphasizing cold water applications. The primary outcome was the number of individual sick days, secondary outcomes included cold symptoms and gastroenterological symptoms. Weekly KC activities were documented; teacher expert interviews and focused ethnographies conducted. Results: Nine kindergartens (n = 247 children) with four clusters were randomized (IG n = 125, 4 kindergartens, WL n = 122, 5 kindergartens) groups. The IG had significantly fewer sick days (1.22 mean days, SD = 3.11) than the WL group (2.55 mean days, SD = 4.10), with an incident rate ratio of 2.17 (95% CI, 1.22–3.86). No harms were reported. Qualitative data highlighted high acceptability and integration of KC. Conclusions: The Kneipp intervention significantly reduced sick days and was well received in kindergartens.