Summary: Respiratory tract infections are among the most frequent diseases in children. They are associated with substantial health and economic burdens, prompting interest in interventions aimed at reducing these burdens. Some reports suggest that dietary interventions or food supplements, vitamins and mineral supplements, or microbiota modifiers may enhance immunity and reduce the risk of or treat respiratory tract infections, including SARS-CoV-2 infections. The purpose of this article is to help physicians to make rational decisions by providing evidence-based, up-to-date information on the efficacy of interventions potentially influencing immunity and their role in the treatment and/or prevention of respiratory infections in children.