You’re dashing for your subway down a seemingly endless corridor when you hear a sneeze beside you. Then another! Great – not only are you late for work, but you now stand a good chance of getting the flu. Actually, no: because the nasal eruptions come not from a real person, but from digital portraits on screens lining the corridor. The last one offers some advice: with flu season on its way, arm yourself with Redoxon vitamin C. But this wasn’t just a one-off stunt: thanks to an online film, the anti-flu message also went…well, viral.