In this 2-year, multisite, randomized, placebo-controlled trial involving 607 children
with vesicoureteral reflux that was diagnosed after a first or second febrile or
symptomatic urinary tract infection, we evaluated the efficacy of trimethoprim–
sulfamethoxazole prophylaxis in preventing recurrences (primary outcome). Secondary
outcomes were renal scarring, treatment failure (a composite of recurrences and
scarring), and antimicrobial resistance.