As I understand it, vaccines are weakened versions of their much more bad “bigger brothers” so to speak. My questions are: how are they made? and assuming many of the weakened virii? (no longer a virus?) are needed per shot, what kind of quality control is needed/enforced to ensure a full strength virus is not accidently introduced?
Some vaccines are (theorectically) weakened versions of the offensing virus - live polio vaccines fall into this category. Various techniques are used to weaken the virus so it only makes you a little sick, which gives you immunity. Once in awhile, though, you get a batch that had regained its strength and causes the illness it was supposed to prevent. This is one reason why live vaccines have lost their popularity.
One vaccine is not a weak version of a illness-causing vaccine but a close counsin to it, and that is the smallpox vaccine, which is not smallpox at all but the closely related (and far less deadly) vaccinia or cowpox virus. Again, this makes you a little sick (ideally - but there are exceptions) and as a bonus makes you immune to smallpox. At least for awhile.
Some vaccines are dead versions of the disease-causing agent, and thus can not revert to strength and cause illness. As long as it’s really dead - something that can be hard to determine in the case of viruses.
There are even some vaccines that are not entire viruses but only parts of the virus, the parts that trigger an immune reaction. These are in theory even safer than dead-germ vaccines, but you have to be sure the parts you’re using are actually the correct parts to achieve the desired effect.
Not really a direct answer to your question, but:
There are 2 major types of vaccines, live & dead vaccines.
Live vaccines are indeed weaker but still living versions of the disease organism. They can be from a related but less severe disease (for example, cowpox is a non-fatal disease, but closely enough related to smallpox to make you ‘immune’ to smallpox), or a small enough dose that your body can fight it off, and in so doing build up ‘immunity’ to that disease, or a ‘weakened’ dose that your body can fight off. (I don’t know how they weaken it.)
Dead vaccines are doses of the disease organisms that have been killed. But they still have their individual characteristics, so the body identifies them and fights them off (fairly easy to do when they’re dead), and in so doing builds ‘immunity’ to this disease in the future.
Dead vaccines are preferable, in that with live vaccines there is always the risk that in some very small portion of the population, the vaccinated person will actually come down with that disease – their body is somehow not able to fight off this weakened dose of the disease. But for some diseases, there is only a live vaccine. With Polio, for example, a live vaccine was developed first, and used for several years, until an effective dead vaccine was developed.
Finally, vaccines are not effective against diseases caused by viruses.
I’m not sure I understand what you mean here. This one sentence contradicts everything else you have just written. Vaccines are used to protect against viruses.
This is false. Vaccination is probably the best defense we still have against viral diseases. Polio, measles, smallpox, and quite a few other viral diseases have effective vaccines.
My guess is that he meant to say “vaccines are not effective against diseases caused by bacteria.”
Whoops! Forget that sentence entirely. (I was thinking of antibiotics and viruses.)
Sorry, but it was the middle of the night when I wrote this and first tried to post it.
Hey CurtC,
This, too, is false. You have probably been vaccinated with DTP (Diptheria, Tetanus, Pertussis).
Hey t-bonham@scc.net,
This is false. Sabin’s live polio vaccine (1957) was launched several years after Salk’s dead vaccine (1955). In addition, the statement that “Dead vaccines are preferable” is suspect. For example, the live polio vaccine was largely preferred to its dead cousin.
-Apoptosis
Ask yourself why the live polio vaccine was preferred.
Mainly, because it was the vaccine-on-a-sugar-cube and a heck of a lot easier to administer than a shot in the arm to massive numbers of children. And it was largely favored only in the US - I think Europe switched over to solely dead polio vaccine many years ago. Live vaccine was responsible for numerous actual cases of polio over the years, some fatal. Someone infected with the live vaccine was contagious and could (and sometimes did) pass the illness on, with some unfortunate results.
Dead vaccine can not cause polio. Period. From a medical and public health viewpoint it IS better because it’s safer.
Hey Broomstick,
You will note that I said the statement “Dead vaccines are preferable” is “suspect”, not “totally incorrect.” Since you bring it up, however, here are some points to ponder.
-Polio is transmitted via the fecal-oral route. What logically makes more sense: a vaccine that is injected, or a vaccine that is injested? This turns out to be important as only the latter will provide mucosal immunity to polio. The Salk vaccine still allows a person to act as a carrier.
-The Salk vaccine requires booster shots every 5 years. The Sabin vaccine provides lifelong immunity after a regimen early in life.
-Reversion of the Sabin vaccine to a neurovirulent strain is extremely rare (roughly 1 in 3 million). This is deemed acceptable based on the thousands upon thousands of lives it has saved.
This is a half-truth. Dead vaccines do not cause disease if they have been properly inactivated. In fact, the Salk vaccine was responsible for 260 cases of poliomyelitis, including 10 deaths. I realize this has long since been corrected.
I stand by my statement.
-Apoptosis
Well you got some good answers and bad answers here.
Basically there are two kind of vaccines; Killed and live attenuated. Killed is exactly what it sounds like. It is virus that has been killed, and is no longer pathogenic.
More interesting, though is live attenuated virus. This is a viral strain that has been altered, and thus weakened. Attenuation is done a variety of ways. In the old days viruses were attenuated in simple ways. Heat, alcohol, and other chemicals can denature (unravel) the DNA or RNA in a virus. Now though, attenuation is a veritable art form. Geneticists can add or remove genes. By altering the genes that are essential in pathogenicity, a dose of virus can be given that will confer immunity while not causing illness.
There is an advantage to live attenuated viral vaccine. Because the virus is live, immunity is generally more balanced. This means the body’s immune response is to more than just a response to a single cellular protein as it often is in killed virus. This is due to the myriad of proteins that an active virus both secretes and carries. So a live virus confers a better cellular response, and thus a longer lasting immunity.
However, even an attenuated virus has more risk associated with it. Chemically attenuated viruses have the highest potential threat level because often it isn’t possible to get a consistent level of chemical action so there may still be pathogenic viruses in the dose. Thus, attenuated vaccines are rarely of highly pathogenic strains.
This is quickly becoming irrelevant though, because genetically altered attenuation is very consistent. A section of genome may be removed, and that virus may be grown in culture, producing millions of clones of the weakened virus. Although there can certainly be a mutation that would cause the offspring to not be an identical clone of the parent, there is very little chance that the mutation would increase virulence due to the size of the removed section of the genome.
The most relevant problem with live vaccine is that it is not safe for the entire population. The young, the elderly, and the immunosuppressed should not take it. The introduction of even a mildly pathogenic strain can throw these folks into a dangerous full blown immunoresponse.
Right now, in fact, the nasal flu vaccine (FluMist) that was used this past fall, is live attenuated, and in UK they still give quite a few vaccines that are live including MMR.
Just for the record, I use viral vaccines as an example, but there are many examples of bacterial vaccines, from Anthrax to Yersenia.
Now to answer your questions:
Vaccines are grown in culture. Flu vaccine is grown in eggs, while bacterial vaccines are grown in big bioreactors. It depends how easy it is to grow your organism. Which can be tricky as pathogens are often very difficult to culture.
As for how you know you aren’t being over-dosed with vaccine, studies are done to determine the optimal dosage. First studies would be done with animals, and then they are moved to human clinical trials. Dosage is determined by taking viral titer regularly in the blood stream after dosing. This also help determine how much immunity is conferred.
Hey light strand,
FYI.
Heat and chemicals (e.g. formalin) are methods of creating killed vaccines, not live attenuated vaccines.
-Apoptosis
I have some questions about vaccines as well.
Well, maybe it’s not quite the same. I want to know about travel shots.
I’ve travelled quite a bit and have had tons of jabs. I began travelling back when they were still giving Cholera shots. In fact, my immu booklet is two booklets stapled back to back because the first one was full.
I seem to recall some were increasing doses. Some decreasing, which was always confusing. Some were good for ten years! Usually they were the most painful.
I weigh 100 lbs soaking wet and often had a bad reaction to these shots.
As I would be lying in a pool of my own sweat some microbiologist would be standing over me explaining to the mister why this happens to me. Blah, blah, you’ll be okay in a minute, blah, blah, something.
Needless to say I never did get a decent explanation.
But I remember clearly the day I discovered that everybody got the same dose regardless of weight.
So I was always convinced the problem was that me and the 200 lb man beside me in the waiting room both got the same dose.
It just seemed so unfair.
Anyone care to set me straight?
At the risk of being pedantic (oh, hell, for the sake of being pedantic):
- The vaccinia virus used as smallpox vaccine today is not cowpox virus.
- There are more kinds of vaccines then “killed” and “attenuated.” There are also vaccines against bacterial diseases that are not made from the killed bacteria themselves but are toxoids that, when injected, produce an immunity to the toxins produced by the bacteria (e.g., diphtheria, tetanus).
- “The most relevant problem with live vaccine is that it is not safe for the entire population.” This isn’t true. It depends on the vaccine.
- “The introduction of even a mildly pathogenic strain can throw these folks into a dangerous full blown immunoresponse.” What in the world is a “dangerous full blown immunoresponse”?
- “Vaccines are grown in culture.” Not all vaccines. The first hepatitis B vaccine was derived from human blood.
- “Dosage is determined by taking viral titer regularly in the blood stream after dosing.” I think you mean the viral antibody titer.
- “This [the antibody titer] also help[s] determine how much immunity is conferred.” Helps, yes, but it is also necessary to do tests to see if the vaccine really works. The presence of antbody does not alwasy mean that the individual is protected.
- “So I was always convinced the problem was that me and the 200 lb man beside me in the waiting room both got the same dose. It just seemed so unfair.”
For vaccines, the precise dose is not all that important; one half or even one tenth the standard dose would probably work for most people and double the standard dose or even more would probably not cause very many more side effects. So the same dose of vaccine is generally given to all adults, regardless of their weight. (I sympathize with you. I remember a 110 lb army recruit who was accidentally vaccinated with typhoid vaccine twice the same day, once in each arm. He was REALLY sick.)
You see what I mean?
This “The precise dose is not that important”, kind of thinking, is just what I’m talking about.
Wouldn’t you think that MICRObiologist’s (the immunization jabs are always in this dept.) would be a little more concerned with dosage? Well, I would.
And they’re always trying to pawn off some sketchy story about some nerve that relates to snakebite or some other thing that sounds distinctly like, Blah, Blah, Blah, when you’re lying in a pool of your own sweat !
I grant they were correct about the, ‘you’ll probably be okay in a few minutes’, with a few exceptions (yellow fever) I was.
There is no such word as virii. The only acceptable plural of virus is viruses.