[whiskers]

Your vet is right. He is still very susceptible to picking up the diseases he's been vaccinated for.

However from a socialization standpoint... you still need to get him out. Do you know if there are a lot of parvo cases in your area? That's the biggest concern, some areas have a higher incidence of parvo, more loose dogs, what have you and in that case I'd be more cautious. In general though the risk of him picking up a disease is small, but the risk of him being cooped up and undersocialized is far greater. I definitely would not take him to dog parks or pet stores but a stroll around your neighborhood is probably fine.