Clinical studies and meta-analyzes have shown that reduced levels of 25 (OH) D in the blood contribute to impaired immunity and stimulate excessive inflammation that adversely affects the health of children: the risk of developing bronchial asthma (BA), obstructive bronchitis, and allergic rhinitis increases. The main purpose of this review is to summarize the current literature data on the relationship between vitamin D, VRI and other infectious diseases with a clinical example.