So my puppy has had his first shots. This weekend he got injured and it took all my extra money to get him fixed. His second Parvo shot is supposed to be today. Will it hurt him if I make him wait an extra two weeks or will that null and void the first shot?

It only takes one shot at the right time to protect a puppy from parvo. So why 3-4? It is easier to give a shot that tell if the time is right. A shot won't take until immunity from the mother wears off. What the puppy needs is one shot between when the immunity wears off and 2 weeks before it is exposed to parvo. Best thing is to keep it away from anyplace frequented by unknown dogs.

For a more complete and authoritative explanation see Canine Parvovirus, What you should know about I trust the AVMA's site more than one somebody Googles up. Tons of sites out there with advice ranging from useless to dangerous.

So does this mean the shot won't keep it from being infected at some point? I thought the sequence of three was to create an immunity to it?

Its not about multiple shots, just hoping to hit the right window with a shot before the puppy is exposed to parvo at the wrong window.