I know that technically The Thing isn’t a virus, but it is an organism that infects people. Granted it eats and overtakes its host but it is very infectious and extremely contagious as far as alien absorbing creatures go.

John Carpenter’s remake of The Thing is a brilliant and terrifying masterpiece.
Kurt Russell is stationed in Antarctica along with Wilford Brimley, T. K. Carter, David Clennon, Keith David, Richard Dysart, Charles Hallahan, Peter Maloney, Richard Masur, Donald Moffat, Joel Polis, and Thomas G. Waites. A Norwegian helicopter is chasing a dog trying to kill it and the dog runs into the American camp. The Norwegians accidentally kill themselves and the dog ends up staying in the camp.
Russel and Dysart fly to the Norwegian camp and find everyone dead there. They also find a very strange body that the Norwegians tried to burn. They bring the body back to camp to autopsy.
They find the dog trying to assimilate all the other dogs and realize after autopsying both the dog and the strange body that an alien creature is taking over the bodies on a molecular level.
Eveyone is paranoid and everyone doesn’t trust each other.
I love this movie. It’s intense and suspenseful and edge of your seat terrifying. Rob Bottin’s effects are amazing and Carpenter has crafted an excellent masterpiece of horror.