The difference is in how the viruses replicate. Chicken pox has a very reliable replication and thus has fewer mutations. The flu and colds have poor replication leading to much more variance as the disease spreads. The virus mutates around your immune defenses and is thus able to spread again.

People often get sick after taking the flu vaccine. They do not catch the flu. What I think is happening is other viruses contaminate the vaccines during the manufacturing process. Since we don't usually come in contact with mouse viruses you have no existing immunity. The bigger concern is the long term effect of these viruses.