There are three main findings in this retrospective cohort study of the impact of viral multiplex rtPCR. First, the majority of patients with viral RTI received antibiotics and antibiotics were discontinued after viral detection in only a minority of patients. Second, when biomarkers, radiologic presentations and antibiotic pre-treatment were taken into account and categories of clinically bacterial and clinically viral infections were created (which more closely reflect clinical decision making), the multiplex rtPCR showed a greater impact and considerably improved correct management of clinically viral infections, from 67 to 100% among children and from 34 to 62% among adults. Third, the impact of rtPCR testing seemed to be more accentuated in children than in adults. More children than adults had an appropriate discontinuation of antibiotics, and the overall management of viral infections was superior in children compared to adults. Importantly, but with the caveat of small numbers, there was no evidence that outcome was worse in those with viral etiology who discontinued antibiotics compared to those who did not.