A number of other vaccines provide immunity response but do not offer protection from viral inoculation. Which means you still contract the virus and it still replicates in your body and you still shed live virus until your body’s trained immunity response out performs the viral replication rate. You are still contagious during that window. The chicken pox / shingles vaccine is an example of this effect. You can and will infect those around you with chicken pox even though you personally are vaccinated.