In phase II studies, in which volunteers were inoculated with either HRV39 or Hanks, subjects were randomized to receive intranasal ruprintrivir (8 mg) or placebo sprays as prophylaxis (2 or 5 times daily (2 times per day or 5 times per day) for 5 days) starting 6 h before infection or as treatment (5 times per day for 4 days) starting 24 h after infection.