An average person touches his or her face about 3000 times per day, and with it brings residue and bacteria from what ever that person touched in close contact with mouth, nose and eyes. From there the eventually dangerous organisms and viruses can travel into lungs, digestivesystems and brain to live long and prosper.
That is exactly what the new influensa does in this movie. The perspectives are many from all stratas of existance: the medical researcher trying to track down the point of origin for the flu, the immune father who loses wife and son and now tries to protect his daughter, the director of the institute of prevention of infection desperately acting to keep all cogs of the machinery together, There is no clear antagonist. All hinderances are mostly people just doing their job, or fully understandable security protocols.
The film moves slow, with a distant, but detailoriented photography. The mood is solemn and there is almost like we're watching a dramadocumentary. The science is spot on, and the scientists act like scientists, not like megalomanical madmen. The general tries to keep the peace, not bomb the world to sterilise it. All characters act like people, not cardboard cut outs.
Some, on this site as well, have complained it is too slow, and that this is not an apocalyptic movie. Who told you it would be? This is the most accurate depiction of a true pandemic I have see. As a complete opposite we can show Outbreak (Petersen, 1995) where the science and drama take a backseat to the thriller. Not so in Contagion.
Is it a horrormovie? No. Is it a thriller? Not really. It is a characterstudy of people and a society infected both by a sickness but most dangerously by fear.