Effect of Oral Probiotic Streptococcus salivarius K12 on Group A Streptococcus Pharyngitis: A Pragmatic Trial in Schools

Abstract

Background: The aim of this study was to examine effectiveness of oral probiotic Streptococcus salivarius K12 in preventing group A streptococcus pharyngitis in 5- to 14-year-old children at high risk of acute rheumatic fever. New Zealand has high rates of acute rheumatic fever among Māori and Pacific children. Children were already enrolled in a school-based Ministry of Health throat swabbing and treatment program. Children self-identified and reported sore throats daily and were swabbed twice weekly. Methods: A total of 1314 children were quasirandomized (based on odd or even birthdates) to receive either K12 (2.5 × 109 cfu per lozenge) or placebo lozenges and continued observed daily trea..