Nomen Nescio wrote:
James Donald writes:
The original vaccine was based on cowpox, the nearest relative of small pox. However it was insufficiently effective and reliable, and so was furtively replaced by a weakened strain of smallpox, which was grown on cows. The sellers of the vaccine continued to represent it as cowpox, but it was in fact a mild variant of the real thing, smallpox.
One reason for ending routine smallpox vaccinations was fear that the vaccine might re-evolve virulence.
You are full of shit. The smallpox vaccine is not made from cowpox or from smallpox (variola) virus. It is made from the vaccinia virus. Did you ever wonder where the word "vaccine" comes from?
The reason routine smallpox vaccinations ended was because some people have a bad reaction to the vaccinia virus, even though a strain is used that is generally benign. Since the vaccination was thought to confer no benefit and does carry some risk, it was discontinued.
Do a google search on "smallpox vaccine" next time before you spout off with ignorant garbage like this.
And google is of course the fount of all wisdom? As I think someone else pointed out, the original vaccine *was* based on cowpox. Inoculation with dried up pustules from smallpox victims had been known about since at least the 10th century in China and by the 18th had spread all over Asia and Europe. However there was apparently a 1-5% chance of causing smallpox, so it was a desperate remedy. Jenner had the idea of using cowpox pustules from milkmaids. They thought that cowpox was caught from cows so called it "vaccination". As you say (& I didn't realise till I looked it up just now) it was later based on vaccinia virus, which is of unknown origin. Just turned up in a lab one day. It is called "vaccinia" because it was first discovered in a vaccine. It probably isn't a recent variation on either smallpox or cowpox because parts of its genetic sequence are less close to either of them than they are to each other. (Which might be a clue that other pox viruses could be used for immunisation as well). Vaccinia is *not* harmless - people have died of it, and it has become endemic in the water buffalo population of India, from where it sometimes infects cows and very rarely infects humans. It might possibly have originated as a bovine disease, maybe introduced by mistake for cowpox Smallpox vaccine is still apparently available to people who work in labs on other poxes, and to medical staff in the (small) part of West Africa where monkey pox is a human health problem. Just out of interest, cowpox is *not* a natural disease of cows, but of rodents, probably originally susliks or gerbils. It seems that cows can catch a mild form of it when in close proximity to rodents (such as in 18th century English barns in winter) as can humans. Similarly monkey pox is originally a disease of squirrels, but was noticed first in monkeys. Smallpox isn't likely to be a war-winning weapon, though it could cause a great deal of terror. It spreads slowly enough so that any country whose pharmaceutical factories haven't been blown up by cruise missiles could probably tool up in time to prevent an epidemic, helped by some sensible quarantines. There are many potential low-tech vaccines. It kills 10-30% of victims, slowly, and many people in Europe and Asia have some hereditary immunity or residual effect from vaccination. If you used it against an army you are likely to end up with very, very, angry enemies, mostly still capable of fighting. There are many other poxviruses such as volepox. There is even one endemic to the USA: skunkpox. You Americans just have to inject yourself with pus from a poxy skunk if you are worried. Personally I'm much more scared by nerve gasses. No time to prepare, no practical precautionary measures anyway. Details not from Google, but from Gilbert &7 Allison (1998) "Vaccination and Immunisation" in Hugo & Russell "Pharmaceutical Microbiology", 6th edition, (Blackwell's Oxford) and also from Fenner (1996) "Poxviruses", chapter 84 of "Field's Virology", 3rd edition (Lippincott, New York). Ken Brown (who is a microbiologist when he has his lab coat on)