Considering the differing opinions regarding the role that the wearing of nail polish and hand or wrist jewellery might have in impacting disinfection during the handwashing process, this report aims to review the current clinical evidence and evidence-based guideline recommendations for this procedure. [...] Additional references of potential interest are provided in Appendix 5. Summary of Study Characteristics A tabular description of the included study characteristics is provided in Append ix 2. Study Design What is the clinical evidence regarding the effect of health care workers wearing nail polish or hand and wrist jewellery on infection transmission? [...] Interventions and Comparators What is the clinical evidence regarding the effect of health care workers wearing nail polish or hand and wrist jewellery on infection transmission? [...] Summary of Critical Appraisal A tabular description of the critical appraisal of the included studies is provided in Appendix 3. What is the clinical evidence regarding the effect of health care workers wearing nail polish or hand and wrist jewellery on infection transmission? [...] Summary of Findings The main findings and guideline recommendations are provided in tabular format in Appendix 4. What is the clinical evidence regarding the effect of health care workers wearing nail polish or hand and wrist jewellery on infection transmission?