Greetings.
Why is it that dogs, cats, and ferrets can be vaccinated against rabies with a single shot every year, whereas human vaccination against rabies involves (at least until recently) a long and complex series of painful shots? Why can’t humans use the same vaccine as the one for animals, and what would happen if they did?
Regards,
Psychonaut
Disclaimer: This is an educated guess. I don’t know the specific trial data.
Psychonaut: A fundamental difference exists between animal and human rabies vaccination. Animal vaccination prevents acquisition of infection whereas human vaccination prevents death once infection is acquired. (Trivia question: What is the only infection in humans with 100% mortality?-see answer below)
The difference in protocols is a reflection of this distinction. Keep in mind, also, that once an effective protocol is developed for humans, modifications to that protocol become a tough sell, even if they are shorter or more comfortable. The price paid for ineffective treatment is death of the patient.
You could ask why don’t we vaccinate all humans before they acquire rabies (like we do with our pets)? My hunch is that in the cost-benefit-analysis, you do more harm than good. Rabies transmission to humans is uncommon. Therefore, even rare side effects of vaccination have important implications in a large scale vaccination effort. Additionally, by vaccinating our pets, we reduce the viral reservoir, and by extension, the number of human infections.
*****Answer: Rabies
Actually, people at a high risk of being bitten by an animal, ie zookeepers, veterinarians, etc. frequently receive a preventitive vaccine. It’s not cost effective, as choosybeggar noted, to administer it to the general public as the incidence of exposure is low in the general population.
You could ask that, but I wouldn’t. The vast majority of people are unlikely to ever encounter rabies. However, I know that there are some high-risk groups, such as some veterinarians and people whose profession involves the handling of wild animals, who are indeed routinely vaccinated against rabies. I was under the impression that this preventative vaccine involved the same procedure as that used for those bitten by a rabid animal. (Someone please correct me if I’m wrong.)
As to your claim that rabies is the only infection with 100% mortality, I highly doubt that. Do you mean 100% mortality with or without treatment? Many people have survived bites from rabid animals when given the appropriate treatment. And without treatment, I was under the impression that the flesh-eating bacteria was uniformly fatal.
Regards,
Psy
Yes, only infectious disease with 100% mortality w/o treatment. From Emedicine.com
OK. Here’s a page from the CDC detailing the difference between pre-exposure versus post-exposure prophylaxis. Pre-exposure requires 3 intramuscular injections; post-exposure is 5. The long painful series of shots regimen is history.
Human rabies immune globulin is administered after exposure as well.
Make that 99.999% – I read that in the entire history of recorded medicine, one person who got it, and went untreated, actually survived. It’s still pretty damn close to 100%.
It is indeed true that high-risk groups are vaccinated, but not as frequently as pets. I oversee coordination of the rabies vaccination program for animal care staff here that the National Aquarium in Baltimore. The initial vaccination for humans is three shots administered at day 0, day 7, and day 21 or 28. The first two shots are the critical ones; the third just boosts titer. We have one staff member who had been given the first two shots during his military physicals (he’s Air Force reserve) a year ago. When we checked his titer it was still in the protective range. Shots are 1 mL in volume and given intramuscularly in the arm. After receiving the 3-course vaccination, staff members’ titers are rechecked every 2 years. As long as it remains protective (and I’m not sure what exactly the range is–we submit blood samples to the State of Maryland Dept. of Health and Mental Hygiene and they tell us whether the titer is positive [with a value] or negative), no action is taken. Staff whose titers are negative are given a booster.
The populace in general is not routinely vaccinated because, as others have stated, it’s not cost-effective and generally not necessary. There is always the risk of side effects as with any vaccine, and I know people who are allergic to eggs are generally not given the vaccine (we have one staff member whose allergic to eggs…and many, many other things who was given a waiver) unless they’ve actually had an encounter with a known or suspected rabid animal. Everyone who receives the vaccine is given a drug info sheet from the manufacturer which lists common side effects such as pain or swelling at the site, general “malaise”, headache, and dizziness along with a percent of people who actually report experience these (ranging from 34-15%). They also helpfully report how many people have had more severe side effects such as anaphalactic shock and encephalitis or meningitis (extremely few, but the risk still exists).
Post-exposure prophylaxis (what they give you if you’ve been exposed) is slightly different. Those who have not been exposed receive rabies immune globulin intramuscularly, half at the wound site (if possible), and the rest in the butt (reference: Drug Facts and Comparisons…which is about 3 years out of date but is probably pretty close if not exactly accurate for what’s done today). This boosts immediate immunity. They then receive a course of vaccine for long-term immunity (rabies normally manifests in a few weeks but can take longer). Those who have been vaccinated just receive another booster with the vaccine…much less uncomfortable. Based on staff titer values, I can attest that the PEP protocol definitely results in a much higher and longer term immunity–one of our vet techs had an unfortunately encounter with a rabid skunk in a park (and she fortunately was able to convince the rangers that shooting its head off after the incident was not the preferred plan, so they were able to test and confirm the animal was rabid) and has a titer therefore that is 4 fold higher than anyone elses.
Pets are routine vaccinated in this country largely because the primary source of rabies transmission to humans worldwide is pets (particularly dogs). By mandating vaccinations of all dogs and cats in most states (particularly east of the Mississippi where rabies is most common, especially among raccoons), the US has drastically reduced the incidences of rabies exposure. The CDC website lists only 11 cases since 1998…and, as choosybeggar inferred, they all ended in death http://www.cdc.gov/ncidod/dvrd/rabies/Epidemiology/Epidemiology.htm. The website actually lists the detailed case history of 10 of the incidences. It’s not a pretty way to go. Fortunately, PEP is as near to 100% effective as humanly possible. The cases that occur primarily seem to result from exposure outside of the US or situations where the victim does not realize they’ve been bitten by something.
( Hmm…note to self. Must type faster and more succinct replies lest I be beaten to the information. 
)
Wow. Been there and the place is awesome.
I am a veterinarian and have undergone pre exposure prophylaxis. Last summer I had exposure to a rabid cat and was wondering for a few weeks if my kids were gonna win the life insurance lottery.
But I made it;)
I had to received the post-exposure vaccinations in 1995. I was bitten by a dog on the calf, and while there were no puncture wounds, and the cloth of my pants wasn’t even ripped, there was a scratch and animal saliva on the wound. After the “bite,” the dog disappeared (how convenient). There had been several cases of rabies in the County and when I casually mentioned the incident to the Animal Warden (just passing him in the hall and making a joke about him not doing his job), I was told “You need to get rabies shots. Now.” Within an hour I was at the hospital.
At the time I didn’t know that the protocol had been changed and that I wasn’t going to get the series of shots in my stomach. As you can imagine, I was scared shitless.
I received a series of 5 shots (1 shot per week, 1 week apart) in my shoulder. The County’s Workman’s Compensation Insurance Company paid my bill, then collected from the dog owner. The final bill was almost $3,000 for 5 shots. You can see why it would be cost prohibitive to do it wide on a wide scale.
It may be that the B-lymphocytes responsible for the production of the antibodies for the rabies virus has a short life span. The life span and cell line for these B-lymphocytes varies quite a bit, some lines, the B-cell responsible for producing the antibodies to chicken pox for example, have extremely long cell lines which help to protect you against infection over the course of your life. Perhaps the rabies shot is much like a ‘booster’ to trigger the evolution of B-cells which can produce the antibodies to the rabies virus. Just an educated guess.
Interesting fact. Rabies vaccine for use in animals wholesales for roughly one dollar a dose. The vaccine for use in humans (excluding the gamma globulin for post exposure) is made in the same factory but has a different label.
The cost difference is due to possible product liability issues.
Cite…communication with a friend at Wistar Institute.
Thank you. Yes, it is. {shameless plug} Should be even neater next year once we get the Australian expansion open. We’re going to have gray-headed flying foxes (aka really big fruit bats) and tons of birds & turtles (I think our general curator may need to look into a 12 step program for turtle addiction). If you want to visit again, I highly advise coming in September; it’s when we tend to be less crowded (school’s back in session but school groups haven’t started coming through) {/shameless plug}.
Another rabies anecdote: The husband of a friend of mine, who was not raised in a high-rabies area, came back in after walking the dogs one morning and told her about this “very friendly” racoon he’d encountered in a nearby park. And was petting. While with dogs. In broad daylight. She, being Maryland born and raised and savvy to the dangers of overly-friendly nocturnal wild animals out and about in daylight (especially raccoons), immediately insisted he go to the doctor and get the shots. He didn’t believe her about the risk and (this is scary), neither did his doctor. But the doctor called the CDC just to “humor your wife”. The CDC insisted he go the hospital immediately and get the shots, to their surprise/chagrin. My friend asked her veterinarian about getting a rabies vaccination tag like they give to dogs and cats for her husband as a joke but, alas, their distribution is tightly controlled by the state.
Actually, many people maintain high/positive titers for rabies for several years (even decades) after vaccination. This may also be true in animals but I think it’s just considered too much of a hassle to check titers in pets and then ask owners to come back a few weeks later if their pet needs a booster. It would be more costly and would run the risk of people opting to not bother coming back. Much easier to just set a schedule and require folks to stick with it, especially since a lot of folks get their pets vaccinated via low cost clinics or vaccination drives versus via a veterinarian. Given that rabies vaccinations can be given every 3 years (after the first 2 one year apart) as compared to distemper which is given annually, immunity is probably relatively long-lived. There are also studies/trials being done with oral rabies vaccines and wildlife, which wouldn’t be very useful if immunity was short-lived.
You bet. We see that difference frequently when purchasing medications. There was just a big recall of human rabies vaccines (fortunately not the ones we used in the last rounds of vaccinations), too. Liability is a huge factor in all areas of medicine. My supervisor, as an exotics vet at a large zoologic institution, has an annual veterinary liability insurance cost of ~ $200. Compare that with your average medical doctor’s.
Kalhoun or anyone else, can you link me to this? My 10th-grade biology teacher (probably my favorite teacher ever) told us about a case in which a girl in Mexico contracted rabies and didn’t die from it, but lived the rest of her life in a coma. I do education for a humane society, and I recount this anecdote about twice a month to schoolkids in an effort to interest them in not petting wild animals, but I always feel vaguely guilty about not knowing more about this incident and whether it’s even true. I’d love to verify it (or falsify it, so that I could stop telling the kids).
Daniel
There have been a handful of survivors of rabies infections. I do not have the articles, but Dr Larry Glickman (an epidemiologist) and Dr Charles Ruprecht (do not know his area) have written extensively on the subject.
Also there is this:
A case of human rabies with prolonged survival.
Emmons RW, Leonard LL, DeGenaro F Jr, Protas ES, Bazeley PL, Giammona ST, Sturckow K.
PMID: 4589643 [PubMed - indexed for MEDLINE]
Also, interetingly there is an animal that commonly survives infection with rabies virus. I would put it in a spoiler box, but I am not that good. It is…the bat.
HTH,
Mark
You forgot the rest of the cite essential for anyone who wants to actually look it up: Intervirology. 1973;1(1):60-72.
Unfortunately without a readily-available abstract (pubmed doesn’t have one), I can’t verify that the case in question was someone who survived rabies all on their own or with assistance from a vaccine. I may ask our staff librarian if she can find the actual paper without too much hassle since I’m morbidly fascinated by both rabies and the plague (which about 10-15 people in the US contract every year…it’s an occasional problem among the wildlife and domestic cats in the southwest). I’d heard that one person had survived the disease without the aid of vaccines but I’ve never been able to actually find the reference for that.
Two other sites that I found:
http://home.earthlink.net/~webmedic4u/Rabies.html
http://www.emedicine.com/emerg/topic493.htm
both state essentially the same thing:
Bolding mine. Pre-symptomatic vaccine administration seems to be the key. Once you actually show signs of the disease, it’s too late. So it’s very, very important to seek the post-exposure treatment if even the slightest chance of exposure exists.
In my medical micro class three or four years ago, my professor said there was no clearly documented case of someone surviving rabies without treatment. The virus stays exclusively inside nerve cells, making it almost impossible for the body to mount an immune response without help from a vaccine.
Note that the person who got the $3,000 series was not getting the vaccine - he had been exposed so was getting the other post exposure series. I’d be interested to see what the price for the human vaccine series was.
DancingFool
The post-exposure series is the vaccine, with the addition of rabies immune globulin. It’s all the same vaccine, post- or pre-exposure. The only difference with respect to the vaccine is that you get more shots of the vaccine post-exposure (5 versus 3). So the actual vaccine should cost the same per dose whether it’s used pre- or post-. I"ll have to check with the office of the doctor who gave the shots to see how much the vaccine costs. We had to order it through them.
As for what the vaccinations cost the patient, if you are in the group for which it is recommended that you get the pre-exposure vaccine, it will most likely be covered by your insurance (if you have it…and if you’re in a job that puts you at risk to rabies exposure they darn well better have some health insurance for you). For our staff, all they had to pay was the $15 co-pay/shot (which we then re-imbursed since getting the shots was requested by the company) for a total of $45.
While this thread has brought up a number of interesting points, so far I don’t think any of them have addressed my original question – namely, why is it that humans receive more preventative vaccine shots than animals? AFAIK, even a large dog as big as a human needs only one rabies shot per year, whereas a vet or dog catcher needs at least three (and historically possibly many more). Is the dog simply receiving a lower and possibly less effective dosage, or is there some physiological difference between humans and carnivores which mandates the difference in dosage?
Regards,
Psy