The first thing to do is to vaccinate and repel insects as soon as possible when the dog is healthy (45 days later)!
Puppies should eat less and more meals, preferably 3-4 meals a day. Don't insist, give priority to dog food, eat less meat and greasy!
Try not to take a bath before vaccination, in case of catching a cold!
Go out as little as possible to reduce the chance of infectious diseases!