Tuesday, April 14, 2009

educational post: vaccines, part 1 - general information

vaccinations have caused a great deal of controversy in the veterinary field over the past few years. clinic recommendations run the gamut. take major corporate hospital, which we will call Danfield. currently, it recommends anywhere from 8-15 vaccines per year, frequently greater than 5 administered in one visit. then there are the more progressive clinics which offer vaccines on a three year schedule (with the likely exception of rabies, lepto, and bordatella). it's hard, as a consumer and non-veterinary person, to know what is best for your pet. go to 3 different vet clinics, and you will likely get 3 different answers regarding vaccination recommendations.

this post is an attempt to clear up confusion by explaining the very latest vaccine recommendations by the AVMA, with an explanation of what they are and why you should (or should not) get them for your furry friends.

to begin with, we can discuss what vaccines are, how they work, what vaccines are available (parts 2 and 3), and what vaccines you should (or should not) get.

first, exactly how does a vaccine work?

vaccines work by causing stimulation of the immune system. the immune system's main function is to protect the body from foreign invaders like bacteria and viruses. it does this is many ways, but one of the major ways is by production of antibodies - the body's natural antibiotics. vaccines encourage the body to do this. this is accomplished by injecting either a dead strain of the virus into the body to cause immune system stimulation or by injecting a modified live strain into the body. in the case of the MLV strains - the virus is alive, but it has been modified so that it is no longer pathogenic (disease causing). most recently, recombinant vaccines have made a splash. in laymen's terms, these are genetically manipulated to enhance immune stimulation while reducing risk to the patient.

are vaccines good, bad, or ugly?

it stands to reason then that vaccines, while having a host of beneficial side effects, can also have negative effects. these negative effects are only now just starting to be understood and studied. in humans, a sensationalist example would be childhood vaccines and autism. nothing so sensational has occurred in veterinary medicine, although many scientists and specialists suspect that over-vaccination might have something to do with the preponderance of immune-related diseases we see as doctors (immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, pemphigus, lupus, lupoid onychodystrophy, etc). further, receiving too many vaccines at one time in predisposed breeds (pugs, notably) can cause anaphylactic reactions which require emergency treatment. lastly, some vaccines have been directly linked to a very aggressive, often fatal cancer of cats called vaccine-induced sarcoma.

is yearly vaccination really appropriate?

when people ask me this question, i simply ask - how many vaccines have you received in the last 3 years of your life? i can tell you that i have received one, a flu vaccine that my father-in-law insisted i take. other than that, i can't begin to remember the last time that i received a vaccine. so why should our animals be vaccinated yearly? granted, their life spans are shorter than ours, they are probably exposed to more infectious disease than we are, and they often get into fights with other animals - sustaining bite wounds that humans are unlikely to encounter. yet still - yearly vaccines? it has been shown that once vaccinated with a kitten/puppy series and a shot at 1 year that some animals might never require another vaccine in their life, while another animal's immunity from vaccine may only last a couple of years. many prominent names in veterinary medicine believe that the immunity received from routine puppy/kitten boosters and a shot at 1 year old will confer life-long immunity from disease. this isn't strictly proven, but it is accepted knowledge. current recommendations are that vaccines should be received every 3 years (with the possible exception of a few in dogs, which i will cover, as well as the rabies vaccine - which is mandated by law due to human health consequences).

is there an age when vaccinating is more important?

this is the most important point! when puppies and kittens are born, they have a rather wimpy immune system. mom passes along antibodies both through the placenta and through the milk. these maternal antibodies offer protection against diseases that mom has already had, been vaccinated for, or has been exposed to. thus, the puppies and kittens are protected. the PROBLEM with these maternal antibodies is that we don't know when they start to wane (it's different for every individual puppy and kitten). thus, we recommend vaccinating starting around 6-8 weeks of age (vet research has indicated that this is when mom's antibodies start to weaken) and continuing on until a certain point (usually 3-4 puppy boosters, then a 6 month shot, then a year). this way, the babies are vaccinated whether maternal antibodies are present or not. thus, vaccinating puppies and kittens is the most CRUCIAL part of vaccinating. young animals are the MOST susceptible to infectious disease. your 12 year old, indoor cat...eh, you can probably skip vaccines, he's got natural immunity. your 3 month old, pit bull puppy? no way, no how. get those vaccines.

are the vaccines at the coop/feed store/over the counter places acceptable in lieu of a vet visit?

the short answer is a resounding NO. the long answer is a bit more complicated. the vaccines that you can pick up at your local feed store/coop (we can do that here in the south. up north?) may actually be GOOD vaccines. however - part of what you pay that vet visit cost for is 1) proper administration of the vaccine by a licensed veterinarian and 2) proper storage of that vaccine by the licensed vet. it's surprisingly easy to screw up simple subcutaneous administration of a vaccine. it's also surprisingly easy for the door to get left open on the fridge at the coop so that the vaccines go bad, or for the vaccine batch to actually be expired, etc. etc. granted, these things can also happen at the vet's office, but seriously - just pay the exam fee and let the vet do it. you'll be so glad you did pay the $54 for the shots and exam, especially if you meet someone who has a parvo puppy and plunked down $800-3000 for treatment. TRUST me. i see it every single week i work ER medicine.

here's the skinny on vaccines: yes, they have an important place in pet health. no, this should not be a yearly requirement, and the more progressive practices are already moving/have moved in this direction. the truth is that many veterinary offices are afraid of going to 3 year vaccines for 2 very big reasons: 1) money (obviously) - vaccines have been a decent moneymaker for many vets for many years - which is not to say that all vets were vaccinating yearly for financial reasons. until very recently, this was the recommendation of the AVMA. 2) people don't bring their animals in yearly if they're not getting shots. this is important. just because you elect to forego yearly vaccines does not mean that your pet should forego a yearly physical exam. their lifespans are significantly shorter than ours, thus in 6 months - a cat or dog's health can change a great deal. if you skip that yearly exam, then your doctor might not get a chance to diagnose the new heart murmur your cat has developed, the early signs of kidney failure (a very common disease in older cats), the mass you hadn't noticed on your dog's inner thigh, the weight loss, the weight gain, and a host of other physical changes that your veterinarian is trained to see. if you stop getting yearly shots, continue to see the vet once a year (at minimum) for a physical exam.

that brings up an important sidenote: when you do go to the vet for a yearly exam, make sure that they are doing a thorough physical exam on your pet. this involves a very thorough, head-to-toe examination of your pet, as well as auscultation of the heart and lungs (listening with the stethoscope) and a RECTAL exam. a rectal exam is a crucial part of a physical exam. if your vet isn't doing one at each physical exam, you need to request one. there are only 2 acceptable answers for why a rectal is not done: 1) the dog doesn't have an asshole or 2) you don't have a finger. this was taught to me in vet school verbatim, and it's a maxim i live by! as gross as it sounds, the rectal exam provides a wealth of information. here's an excellent article on the topic of the routine physical exam.

1 comment:

Nicki said...

Danfield-very funny, subtle too!