It has been known for a long time that certain viruses can pass between species. Indeed, the very fact that chimpanzees obtained SIV from two other species of primate shows just how easily this crossover can occur. As animals ourselves, we are just as susceptible. When a viral transfer between animals and humans takes place, it is known as zoonosis. And it happens. It's one of the prime concerns regarding the Hendra virus at the moment.

In February 2000 the Wistar Institute in Philadelphia (one of the original manufacturers of the Chat vaccine) announced that it had discovered in its stores a phial of polio vaccine that had been used as part of the program the Geoff has mentioned. They may not have been the same exact vaccines used in testing, but they were from the same batch - like getting one big bowl of punch and sharing it out between glasses, likewise this vaccine was a batch, shared between phials. The vaccine was subsequently analysed and in April 2001 it was announced that no trace had been found of either HIV or chimpanzee SIV. A second analysis confirmed that only macaque monkey kidney cells, which cannot be infected with SIV or HIV, were used to make Chat. While this is just one phial of many, it means that the OPV theory remains unproven.

The fact that the OPV theory accounts for just one (group M) of several different groups of HIV also suggests that even if the theory is true, transferral must have happened in other ways too, as does the fact that HIV seems to have existed in humans before the vaccine trials were ever carried out

When you hear these claims about vaccines and AIDS, knowing that vaccines are in circulation, why does it come across to people as so immediately plausible that you have no reason to question the origins of the theory? What is it that turns an "old wive's tale" into a "conspiracy theory extraordinaire"? QUESTION things that don't make sense. It doesn't make sense that vaccines would cause AIDS because you'd think that if they did, some serious investigation would take place (which it did) and something would be found (which it wasn't).

"Can you prove vaccines are safe?"

No, because that depends on the meaning of "safe".

Understandably, medical doctors define "safety" within the narrow parameters of their discipline, whose aim is to save human lives against physical illnesses. It would be ridiculous for example to ask a medical doctor (in that capacity) whether a financial investment is safe; whether it is safe to befriend a certain person; or whether it is safe to ride an elevator with an extra 10Kg load.

Similarly, as doctors are only trained to "fix" bodies, they (and scientists in general) are unqualified to assess the spiritual danger of vaccination.

Those who have no interest in religion may just as well follow the advice of doctors and get vaccinated, while those who are steadfast in their faith need not use the crutch of science. I think that those who attempt to justify their religious faith with scientific proofs are fools who understand neither religion nor science.

Yuyutsu, this article has nothing to do with religion, so why bring it up? Vaccine safety is determined by meticulous scientific research of the risks, religion or spirituality notwithstanding. Belief does not trump fact - if a blind man is told that the sky is red, does his belief of it being red make it so? No, it doesn't.

You're right, the safety of vaccines is a matter of relativity, as is anything in life. People think it takes wars and tragedies to put billions of lives at stake, but the truth is, billions of lives are ALWAYS at stake, and the point of vaccines is to minimise the risk of diseases. Forget for a moment of risks vs benefits of vaccines, and think instead of the risks of vaccines vs the risks of disease: if you are properly informed, you know that the former is a much more marginal risk compared to the latter.

This is a fact, regardless of religion or spirituality, and neither one is an excuse to disregard facts.

Cohenite, "Isn't it ironic that we have an alarmist froop-loop advocating the polio/AIDS connection just after I make a comparison between the anti-immunists and the AGW believers. To compound the irony, Nature magazine, which was subject to an attempted hijack by he alarmists and is used to spread the AGW propaganda, has declared the polio/AIDS connection "refuted".

You again jump the gun, I only related that the OPV AIDS hypothesis relates only to the historical origin of AIDS, and its proponents have accepted the safety of the modern polio vaccines, but rumours based on a misunderstanding of the hypothesis exist. Science uses empirical evidence and scouring Wikipedia to support your side of the argument is as usual 'shallow'

By the way its Fruit-loop not froop-loop, but then again I don't want to nit-pick!

Additionally I never mentioned anything about being against immunisation, you just can't help putting your foot in that big unintelligent mouth can you?

Get a life

Dear Martin,

<<Yuyutsu, this article has nothing to do with religion, so why bring it up?>>

Because the question whether or not to vaccinate is a religious one, at least for many of us.

<<Vaccine safety is determined by meticulous scientific research of the risks>>

No scientific research has, or ever can, study the spiritual implications of vaccinations, only the medical implications.

<<Belief does not trump fact>>

I give facts their due respect, where they belong, I don't argue facts, but this is a question of religious values and therefore is independent of the facts.

<<if you are properly informed, you know that the former is a much more marginal risk compared to the latter.>>

Yes, if I am only informed of the medical risks but choose to ignore the spiritual dangers of vaccination.

<<This is a fact, regardless of religion or spirituality, and neither one is an excuse to disregard facts.>>

Again, I do not disregard facts, but facts are not everything. Your ideal, for example, of saving human lives, is not a fact but a value, your own: science can never ever prove that it is valuable to save human lives!