Caveat: I did not make up this guideline, obviously, but am just trying to explain why this frequency is recommended by authorities. As I understand it, some countries (e.g. the UK) currently administer only two shots but there seems to be a movement reverting back to three in the future.
The reason for 3 puppy shots is that vaccination takes up where the immunity passed on by the mother (maternal antibodies, known as "MDA") leaves off. Each puppy is different and becomes vulnerable ("window of susceptibility") at different times, anywhere from 8 to about 20 weeks of age.
Here's the scoop:
When the litter is born and the mother's milk comes in, the "colostrum" in the milk contains antibodies to everything (except rabies, I think) that the bitch has been recently vaccinated against or exposed to. This colostrum lasts only about 48 hours but protects the puppy for quite a lot longer. At some point within the next 20 weeks, and this varies by bitch and puppy, the maternal antibodies wear off and the puppy becomes unprotected. This time frame is called the "window of susceptibility". Experts think this window can last anywhere from about 8 weeks to 20 weeks of age. The reason that 3 sets of DHPP vaccines are given to puppies is to ensure that they get protection as soon as their own systems are able to develop their own antibodies - i.e. when they become vulnerable/susceptible. By definition, then, almost every puppy is over-vaccinated but I'm okay with this as they are particularly susceptible to disease at this age and being safe than sorry IN THIS INSTANCE seems a good idea to me, especially in the case of parvo-virus.
In other words, most puppies that get an 8-week DHPP shot will derive no protection from it since the maternal antibodies are still strong enough to be effective in their bodies and will negate the vaccine. But those whose immune systems have matured quickly (i.e. the colostrum is no longer protecting them), will develop their own antibodies from the vaccine and be protected from then on until their one year booster without further shots in the interim. However, since we can't tell which puppies this pertains to and which are still protected by their mother's antibodies, we need to keep vaccinating them.
At about the 12-week mark, the puppies get their second set of shots (this is not considered a booster shot, but rather a second attempt to immunize). For those whose 8-week shots took effect (Group A), this second shot is redundant. However, for an additional percentage of puppies whose maternal antibodies have lost their effectiveness in the intervening weeks (Group B), this shot will enable them to generate their own antibodies and regain protection. The remaining percentage of puppies (Group C) are still being protected by the maternal antibodies and will not derive any benefit from the shot.
At about 16 weeks, the 3rd shot is given and this will finally give protection to the Group C puppies whose maternal antibodies, by now, have ceased to give protection; it will give no further benefit to Groups A and B.
Three puppy shots are given during this short time frame, not to boost immunity, but only to ensure that the puppy responds/develops antibodies from one of the 3 shots. No puppy should be vaccinated before 8 weeks old because the mother's antibodies will negate the vaccine. A waste of time and money and an unnecessary risk to the puppy.
Maybe some day in the future, protocol will involve titering at various points during this window of susceptibility in order not to over-vaccinate, but we're not there yet for a number of reasons. At the current time, titers should not be done under 16 weeks, probably because the dog's immune level hasn't stabilized yet and we haven't figured out a way to measure before stabilization. Furthermore, titers may be artificially high up to 3 months after the last booster and would give a false reading.
In adult dogs that have not been previously vaccinated, maternal antibody protection is not an issue so they should have only one shot and then a booster after a year.
And the one year booster in both cases should be the 3-year (not one year) DHPP.
Last edited by Pugpillow; 11-10-2010 at 10:57 PM.
"You cannot afford to subject your animals, or your children, to medical interventions that you do not understand. The belief system upon which the conventional medical model is founded is so faulty, so corrupt and so dangerous that you simply cannot afford to follow blindly." Catherine O’Driscoll http://www.whale.to/vaccine/driscoll1.html
Hilary & the Pugpillow Gang: Rescues: Denver (10), Tina (7), Murdoch (5) and chihuahua puppy Maximus Spartacus. Always loving my angel-girl Mei-Ling (1994-2009), my cutie-patootie Kim-Soo (1995-2010), my precious Daisy-Bo (1998?-2006), my sweet boyfriend Jake (1997-2010), my little black beauty Betsy (1995-2010), my sweet old grumpy man Gooey (1996-2011), and my sweet gentleman Farnsworth (1998-2012) at the Bridge.
This is great information to help people understand vaccinations. I have forwarded it many times in my rescue network from previous postings here. Can we make this a sticky?
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Excellent....I do not like too over vacinate, but this now makes sense. Yes please make it a sticky to find it easily to share with others.
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We over vaccinate period! Which causes most all issues are fur kids end up with. Allergies, cancer and so on.
These are the current UK protocols, for anyone who is curious.
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