The common cold is caused by a number of viruses, making it hard to tackle the infection with a vaccination or cure. Over half the cases of common colds are thought to be caused by rhinoviruses, but there are more than 100 unique variants of these, and they are constantly adapting and evolving.
Attempting to create a cure would be entering a biological arms race that we would be extremely unlikely to win – by the time we came up with a good drug, the cold-causing viruses would have mutated. Preventing the common cold from spreading is far easier than trying to eliminate it.
