At 6-8 weeks of age puppies should receive their first vaccination; this is temporary and needs to be followed up with another one at 12 weeks. After the 12 week vaccination you can then take your puppy out in public areas.
You can be contagious from a few days up to two weeks or more, depending on which virus is causing your stomach flu (gastroenteritis).
Gastroenteritis is most frequently caused by a viral infection and is commonly referred to as viral gastroenteritis, the stomach flu, or the 24-hour or 48-hour âbug.â This type of infectious gastroenteritis is contagious.