He doesn't need a rabies shot to be out socializing. Start taking him places, work from a distance at first, take lots of treats and praise when he watches people and dogs and other new things. Gradually work closer to things. He needs to see all kinds of different people (different colors and genders, old and young, handicapped, tall and short, etc) dogs, other animals, and other sorts of things (loud trucks, balloons, sewage grates, etc)..
ADCH Mikko (USDAA) SCH-B; (NADAC) EAC, EJC, TN-E, TG-E, VerO; (AKC) NAJ, CGC; (NACSW) NW1 - 8 year old GSD