Recurrent respiratory infections are one of the commonly seen clinical conditions in children. Studies shows that immunity of these children is less compared to healthy children and is said to further reduce as they are subjected to chronic medication such as steroids and antibiotics. s-IgA  plays a major role in first line of host defense against pathogenic microorganisms by inhibiting bacterial adhesion to teeth surfaces, counteracting enzymes like glucoyltransferase, toxins released by streptococcus mutans. Nanosilver fluoride has shown to succesfully arrest caries progression without staining teeth. To our knowledge no studies in literature reported the effect of remineralising agents on s-IgA Levels. Hence the aim of the study is to evaluate and correlate the levels of s-IgA before and after application of Nano silver Fluoride on primary carious teeth in children with and without recurrent respiratory infections.