Abstract: © This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies (either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher. COPYRIGHT 2021 EDIZIONI MINERVA MEDICA LETTERS TO THE EDITOR © 2021 EDIZIONI MINERVA MEDICA Online version at http://www.minervamedica.it Minerva Medica 2021 August;112(4):514-6 DOI: 10.23736/S0026-4806.21.07487-5 The administration of S. salivarius K12 to children may reduce the rate of SARS-CoV-2 infection The Coronavirus disease 2019 (COVID-19) pandemic, provoked by the worldwide spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused millions of infections and deaths worldwide since its emergence at the end of 2019. Unfortunately, natural immunity does not exist within the human population and no effective drug has been found thus far specifically for the disease. Incredibly, scientists from all over the world have developed some effective vaccines at an unprecedented pace.1 Unfortunately, vaccine manufacturing and distribution are two important bottlenecks. For this reason, vaccination schedules are proceeding more slowly than they should and was perhaps expected. While waiting for the current vaccination campaigns to produce the herd effect desired by each individual country, COVID-19 research has produced new lines of scientific thought. For instance, recent evidence showed the possible relationship between the lung and oral microbiotas. Indeed, analysis of the bronchoalveolar lavage fluid (BALF) of COVID-19 patients revealed the presence of elevated levels of oral and upper respiratory commensal bacteria.2 Anatomical and physiological considerations indicate that the oral cavity is the primary source of the lung microbiota community, acquired via aspiration and inhalation.3 Indeed, the microbiota of the lungs overlaps with that found in the mouth. In humans, the prominent taxa in BALF samples include mainly Streptococcus, Prevotella and Veillonella, and these are indeed detected in concurrently collected oral samples. Recent studies have shown that the microbiota in the lungs contributes to immunological homeostasis and can potentially alter susceptibility to viral infection.4 With respect to COVID-19, a particular abundance of Prevotella and Veillonella spp. in the lung microbiota composition has been observed in patients with SARS-CoV-2 pneumonia.5 A report by Iebba et al.6 (not yet peer-reviewed) profiled the oral microbiota of healthy controls and COVID-19-hospitalized patients, discovering the existence of four..