Vaccinations shouldn't be given before 8 weeks so it's likely the puppy had only had 1 jab. There will be some, although not full immunity from about a week after the first jab. To be fair, I would take a puppy out at that age, as it does need socialising and getting used to things, however, I would be carrying it only, not allowing it on the ground. Did she put it down on the ground?