How can a dog who has already had his shots get Parvo?

I know a woman whos puppy died of Parvo the other day. But here's the thing the pup had already had all of his shots. When they took him to the vet (thinking he had some type of worm) the vet assured them it was Parvo. What are the chances and please provide factual evidence if you can. thanks.

Puppies get their first immunity from diseases from their mother's milk. These maternal antibodies usually wear out sometime between 6 and 16 weeks of age. The thing is, every dog is different and even dogs from the same litter may loose their maternal immunity at different ages. This is why puppies get a series of booster shots. While one puppy's maternal antibodies may wear off at 8 weeks, another's may be effective until the puppy is 14 weeks old. If the puppy still has maternal antibodies at the time of an injection, the vaccine will not stimulate the puppy's immune system. In this case, once the maternal antibodies wear out the puppy will not be protected from the disease even though a vaccine was given.The whole maternal antibodies rendering vaccines potentially useless thing aside, parvo is a very nasty virus. Vaccines are not 100% effective and a puppy's body is already stressed from all of the new experiences and growth that a pup experiences in the first few months of life. Just like a person who gets a flu shot sometimes still comes down with the flu, dogs that have been vaccinated against parvo (or any other disease for that matter) occasionally still become sick. A vaccinated puppy is FAR less likely to contract parvo and much more likely to recover if infected, but a vaccine is no guarantee that a puppy won't get sick. Even adult dogs that receive parvo boosters as part of their regular vaccinations can catch parvo if exposed to it (however, in vaccinated adult dogs it's usually not as serious as in puppies).

There are many things to consider, how old was the puppy when it got its shot (1st should be 6 wks, then 9 wks, then 12 weeks - if done closer than that is does not give proper ammunity and can actually weaken the amune system), how many did he have (typical is a series of 3, but is some areas where Parvo is high, some vets are going to 4), were they home given or given by a vet (the vx's that are sold over the counter are not as high a quality as the ones typically given at the vet - Ft. Dodge is not a good company - Merel is a good one) - vets will also stand behind there vx's if given with the proper protocol - store bought vx's also do not have the garuntee that they were stored properly to insure that the vx works (ie proper refridgeration), if given at home, was the full amount given. There are also certain breeds that are more likely to get parvo (labs, rotties are a few - some vets will give more vx's to these breeds) even though a dog has been vx for parvo, if the dog then then exposed to a yard that has had parvo or another dog that is sick, the dog can get sick, but typically it is very mild compaired to full fledged parvo. Another thing to think, was to dog examined by a vet at every vx, if the dog had already been expposed to parvo it can delay onset, but keep the dog mildy sick and then hit later on. Parvo is a sickness that is very easy to tell, yes there are tests that the vet can do in office, but most of the time there is a smell that accompanies the sickness and it is very distinct to Parvo. Along with Parvo you have the vomitting, diarhea, letharic, not eating or drinking, I have seen some people pull their dogs through it on their own (OK it was one person in about 15 years of vet teching) but they need IV fluids, anti biotics to prevent secondary infection (Parvo really tears up the gut), septi-serum ASAP works very well, and round the clock moniterin by a vet. Now that this person has had Parvo in her yard, any dog that she puts in that dog is likely to get it. Parvo can live in the dirt for up to 10years and when conditions are wet it seems to come out more. Bleach is the best thing that kills it - yes that may mean killing your yard, but it is better than killing a dog - anything that dog touched has been contaminated and needs to be bleached or steam cleaned. People can not get Parvo, nor cats, but proper hand washing etc is still recommend when dealing with Parvo to not spread it to another dog. Good luck, constult a vet, make sure that puppies are taken to a vet and given vx - never trust home vx.