From:
Church, Robert Ray (UMC-Student)
Date: 2002-05-10 11:31:00 UTC
Subject: Bob C: Vaccination Reactions
Q: "...I read [in the FML, FHL] about all kinds of reactions and deaths from vaccinations. Arena't they too dangerous [to use]?"
A: Absolutely! Reading about health risks on either mailing list is very dangerous--it makes ferret owners crazy!
Ferret lists ALWAYS over-report disease when compared to the population as a whole. It is sort of like reading a veterinary journal; you only read about diseases, not about happy, healthy animals. Also, most diseases reported are those at the end of a ferret's natural life, which makes them appear to have more importance than they deserve. Think about it; you have to die of SOMETHING! In ferrets, diseases of old age include various cancers and heart disease. Ferrets are only biologically designed to live about five years, and MOST diseases start kicking in about then, as the body loses its ability to ward off disease or fix mistakes in DNA.
The same over-reporting of problems is true regarding ferret vaccinations. Vaccinations are essentially harmless UNLESS a bad reaction takes place. There are a number of people who believe inoculations cause long term health problems, but data supporting that position is meager (besides, other than a vaccination NOT resulting in a full-blown disease, how is being inoculated for canine distemper by injection different than catching it from a neighbor's dog? The reaction of the body is virtually identical, which is why vaccinations work, and polio and smallpox is no longer the public health problem they were just 40 years ago). The real problem is the ferret can form an allergy to various proteins in the inoculation, causing a systemic allergic reaction that results in the ferret going into shock.
In terms of anaphylactic shock, what is the risk factor for ferrets to be vaccinated against canine distemper? Risk is defined as the number of occurrences per number of trials; if out of 10,000 vaccinations, one ferret had a bad reaction, then the risk of a bad reaction would be 1/10,000. Now, out of all the bad reactions, how many result in death? One out of hundred? If that is the case, then you can expect one ferret out of 100,000 ferrets vaccinated to die from inoculation complications. Is this a fair assessment? Probably not; virtually ALL ferrets have been inoculated against canine distemper prior to sale, large ferret farm and hobby breeder alike. These vaccinations are repeated for a large majority of these ferrets at least a couple of times during their lives. Yet, each year, only a handful of ferrets die after receiving a distemper shot.
We do have a problem; the numbers discussed above are imaginary. We don't know the actual number of ferrets that live in the USA, how many are vaccinated, how many have bad reactions, and how many die. I have NO way to prove or disprove the actual risk without first having actual numbers. BUT, we can sneak around the problem by looking at a smaller population of ferrets--those who have owners that post on the FHL and FML.
After an extensive search on the FML and FHL archives (I burn the archives to CD for ease of search), I have found the risk of reaction (of any type) to canine distemper vaccine to be about 1/100 (assuming those not reporting anything as not having reactions), and death from vaccination to be roughly 1/35 of the reactive group. In other words, of the instances reported in the two archives, about one of a hundred inoculations result in a reaction, and one out of thirty-five reactions result in death. If we work backwards, we might be able to come up with a rough assessment of relative risk for the population as a whole. Assume the total population of ferrets in the US is about 4 million (a fair guess). We know virtually ALL ferrets have been vaccinated prior to sale at a young age, so we can assume the entire population of ferrets in the USA has been vaccinated at least once in their lives. Using the FML and FHL archives, an average of five ferrets are reported to having died per year. This number is over-reported because health problems as a whole are over-reported in FML and FHL archives, but that's ok to make a worst-case guess, if we realize the actual numbers are smaller. During the time period of the archives, let's make an assumption that the average number of people on the lists number 4000, each owning about four ferrets. Again, actual numbers are much smaller; I have picked numbers I KNOW are larger than in real life so I can control the location of error even though I can't control the degree of error.
Here's the math: 4000 people owning four ferrets each is a population of 16,000 ferrets. Since, on the same lists, the rate of reaction to vaccination was reported to be about 1/100, we can expect about 160 bad reactions per year. Of those bad reactions, with a death rate of 1/35, we can expect about 4 to 5 deaths per year. Since this extrapolated number is about the same as the actual reported number of deaths, even if our assumptions are wrong, they don't change the outcome.
Extrapolating to the ferret population in the USA, assumed at about 4 million, which means we can expect 40,000 bad reactions, resulting in 1143 deaths. See why I said the FML and FHL over-reports specific health problems? If 1143 ferrets died per year from bad reactions from vaccinations, the vaccine would be pulled from the market! I can't tell you how many ferrets die per year from reactions to canine distemper vaccine, but it is nowhere near 1143 ferrets! Nationally, the number is somewhere between 20 to 30, or so (based on reaction rates published in the vaccine literature and estimated ferret populations, as well as reports in reviewed literature).
This is a tremendous rate of error, illustrating the mistake of using ferret lists as a guide to the health problems of ferrets. In fact, my estimate is artificially low because I assumed larger numbers of people reading the lists, for longer periods of time. If real numbers were used, the final US estimate would exceed 2000 ferrets dying annually from canine distemper vaccinations--100 times more than the actual numbers.
That is NOT to say there isn't value to be gained from looking at FML and FHL lists, if you discard the numerical values and concentrate of relative values instead. For example, while adrenal and pancreatic disease are over-reported compared to the population as a whole, the reports of one compared to the other are proportionally correct. In other words, even though adrenal disease is over-reported, the relative reports of adrenal disease is proportional to its occurrence in the overall population. For example (and these are imaginary numbers used to illustrate the example), if people report 100 instances of adrenal disease and 25 instances of pancreatic disease, while both numbers may be erroneous compared to the actual disease rate of the ferret population, relative to each other, the 4:1 proportion MAY be correct.
So, if you base your objections to vaccinating your ferret based on problems listed in ferret lists, you are making a serious mistake. Why? Because while the risk of reaction to canine distemper MAY be as high as 1/100, with 1 out of 35 dying (as reported on ferret lists; the actual numbers are MUCH lower), the chance of a ferret living through canine distemper is nearly zero. In other words, the risks of death by distemper greatly outweigh the risks of reaction and death caused by vaccination reactions.
The bottom line is that while ferret lists are wonderful places for getting help, receiving support, and finding answers, they are terrible places to shop for data to show disease or vaccination reaction rates. These numbers are ALWAYS vastly over-reported, leaving people with the impression that ferrets always get adrenal disease, languish from cardiomyopathy, suffer from low blood sugar, and die from canine distemper vaccinations. In truth, the risk of a ferret having a reaction from a canine distemper vaccination is roughly proportional to a human having a reaction to a vaccination for measles. Considering the risks of NOT vaccinating for canine distemper, the risks of reaction are well worth it. As for the risks of ferrets being "poisoned" by vaccinations? Well, perhaps there is a problem that is yet to be investigated and reported. Considering other environmental risks faced by ferrets, including breathing second-hand smoke, being killed by recliners, or in washers, dryers, and dishwashers, and even just being stepped on, I figure the risk from vaccination to be acceptable. And IF you have ever seen a ferret suffer a horrible, lingering death from canine distemper, you would probably agree.
Bob C