A Pilot Phase 2a, Randomized, Double-blind, Placebo-controlled Study to Explore the Antiviral Activity, Clinical Outcomes, Safety, Tolerability, and Pharmacokinetics of JNJ-53718678 at Two Dose Levels in Non-Hospitalized Adult Subjects Infected With Respiratory Syncytial Virus

The purpose of this study is to explore the antiviral effect of JNJ-53718678 at 2 dose levels (80 milligrams \[mg\] and 500 mg) once daily for 7 days in adults with Respiratory Syncytial Virus (RSV) infection, as measured by RSV viral load in nasal secretions by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay.