Smallpox Vaccine: Does it Work?

By Randall Neustaedter OMD, LAc, CCH 


The debate over use of the smallpox vaccine has focused on the risks of side effects and deaths caused by the vaccine, as well as the problems associated with the vaccine's outmoded technology, but these discussions have ignored questions about the vaccine's effectiveness. Authorities insist that smallpox vaccine was responsible for eradication of one of humanity's greatest scourges (WHO, 1980). It may therefore come as a tremendous surprise that throughout the nearly 200-year history of smallpox vaccination thoughtful physicians and a veritable army of citizens doubted that the vaccine worked at all.

Four factors have contributed to skepticism of smallpox vaccine's effectiveness. First is the dubious notion that lesions from cowpox, a disease of cattle, could prevent smallpox, a related but different human disease. Second, during the nineteenth century, which preceded modern bacteriology and the age of refrigeration, it was impossible to know exactly what was in any given dose of vaccine. Third, the reported increase of smallpox disease in communities following the introduction of vaccination seemed to contradict the claims of vaccination proponents. A fourth disturbing fact is the total absence of any carefully controlled efficacy studies of the smallpox vaccine.

Does cowpox prevent smallpox?

The idea for a smallpox vaccine obtained from cowpox lesions arose from a superstition among milkmaids in England. Those maids who purportedly contracted cowpox pustules on their hands from the udders of cows were subsequently immune to smallpox. Or at least so went the story. Cowpox is a rare, benign disease of cows in Great Britain. It causes bluish lesions on the cow's udder, but few other symptoms. In humans it may cause these same symptoms on the hands and a flu-like illness. Today the disease is extremely rare. Horses would get a similar disease, known as grease, or horsepox, which is now extinct. The early vaccines were prepared from both cows and horses during animal epidemics. It was only during the late nineteenth century that cowpox was artificially inoculated onto the skin of calves and harvested for vaccine, and not until the eradication campaign of 1967 that a reliable preparation of the cultured virus existed. Prior to that time the potency of any particular vaccine preparation was unknown.

When a cattle breeder named Benjamin Jesty supposedly found himself immune to smallpox after having contracted cowpox from his own cows, he decided to inoculate his entire family with cowpox lesions. This was in 1774. Such a procedure was well known to the populace, since the practice of inoculation with the actual smallpox virus had been popular in England since the 1740s, with often deadly results. Twenty years after Jesty and others experimented on themselves with cowpox inoculations, Edward Jenner, a notorious self-promoter, went a step further. He inoculated a child with cowpox and then injected the child with a deadly dose of smallpox. Luckily, the child did not die. This experiment led Jenner to publicize his theory of vaccination in 1796, which quickly became an accepted, and required, practice without any scientific experimentation or medical studies to prove the vaccine's effectiveness.

Despite the initial widespread popularity of vaccination, no one actually proved that the cowpox vaccine prevented smallpox, and many critics insisted that the vaccine did not work. Physicians were especially skeptical about the ability of cowpox to prevent smallpox, even if the populace was quick to adopt a variety of superstitions to prevent diseases. Jenner's proof consisted of locating farmers who had previously contracted cowpox and never came down with smallpox. Then he inoculated them with material from smallpox lesions to see if the vaccine would produce a reaction. When it did not he claimed this proved his theory. However, it only proved that these farmers did have antibodies and resistance to smallpox, which they could have acquired from previous exposure to the disease. Not everyone exposed will suffer the consequences of obvious infections. Physicians came forward with hundreds of cases where an individual farmer had contracted cowpox from cows, but later developed smallpox nonetheless. Jenner dismissed these claims out of hand. Perhaps the medical profession's terrible experience using inoculation with material from an actual smallpox lesion and subsequent deaths created a situation where authorities felt desperate to adopt a safer alternative. As it turned out the death rate caused by cowpox vaccination was lower than results with the previous smallpox inoculation. Cowpox was clearly a safer substance, and hopes ran high that it would work. It was only after the vaccination campaign was in full swing that the dangers of the new vaccine came to light, and its failings became widely broadcast.

What is in that vial?

Early doubts about the vaccine's efficacy focused on its questionable source. It was hard for anyone to imagine that pustular lesions from a cow's udder could prevent disease in humans. There was a natural and understandable aversion to applying such noxious material to one's skin. Jenner attempted to use material from horses' infections, the now extinct disease known as horse grease. When this was poorly accepted he reverted back to the use of material from cows. In fact the new cowpox vaccination often did transfer other contagious and deadly diseases to recipients, especially syphilis, leprosy, and tuberculosis. The populations of England and continental Europe were well acquainted with the extreme danger of using vaccine prepared from the actual smallpox disease (variolation), which was outlawed in England in 1840, and they were loathe to accept any other form of inoculation with diseased material. Vaccination was often forced upon a population that would otherwise judiciously refuse it.

The transfer of a secondary disease is not unique to smallpox vaccination. During the modern era, several diseases have been transferred to vaccine recipients including a monkey virus that has caused innumerable cases of cancer, even 40 years later, from a contaminated polio vaccine given in the 1960s, stealth viruses that cause chronic fatigue syndrome, and possibly the AIDS virus through a live polio vaccine campaign in the Congo (Neustaedter, 2002).

Live vaccines are grown on animal tissues or animal cell cultures. Because of the possibility of contamination from these tissues, vaccines always carry the potential of infecting recipients with these contaminating organisms. Modern vaccines are screened as carefully as possible, but manufacturers can only find the organisms for which the tests were designed. Other contaminating viruses will not be detected. Even modern vaccines contain viruses from chickens and other animals that could potentially cause disease in humans. Monkey viruses contained in vaccines were considered unable to infect humans until the SV40 virus (the fortieth simian virus identified) was found to cause cancer in vaccine recipients and their children. Older vaccines had less stringent manufacturing and testing procedures. In June 2002, Aventis Pasteur, a French vaccine manufacturer, donated a cache of 85 million doses of smallpox vaccine produced in the 1960s to the US government. It is possible that this vaccine could be tainted with any number of contaminating viruses and bacteria unknown at the time of production. Consumers would do well to question the manufacturing date of any smallpox vaccine before allowing its use.

Post-vaccine epidemics

During the nineteenth and early twentieth centuries, when smallpox epidemics ran rampant, the introduction of smallpox vaccination was often followed by an increased incidence of the disease. Many vaccine critics accused the smallpox vaccine of precipitating these epidemics. A disastrous smallpox epidemic occurred in England during the period 1871-1873 at a time when the compulsory smallpox vaccination law had resulted in nearly universal coverage. A Royal Commission was appointed in 1889 to investigate the history of vaccination in the United Kingdom. Evidence mounted that smallpox epidemics increased dramatically after 1854, the year the compulsory vaccination law went into effect. In the London epidemic of 1857-1859, there were more than 14,000 deaths; in the 1863-1865 outbreak 20,000 deaths; and from 1871 to 1873 all of Europe was swept by the worst smallpox epidemic in recorded history. In England and Wales alone, 45,000 people died of smallpox at a time when, according to official estimates, 97 percent of the population had been vaccinated.

When Japan started compulsory vaccination against smallpox in 1872 the disease steadily increased each year. In 1892 more than 165,000 cases occurred with 30,000 deaths in a completely vaccinated population. During the same time period Australia had no compulsory vaccination laws, and only three deaths occurred from smallpox over a 15-year period.

Germany adopted a compulsory vaccination law in 1834, and rigorously enforced re-vaccinations. Yet during the period 1871-1872 there were 125,000 deaths from smallpox. In Berlin itself 17,000 cases of smallpox occurred among the vaccinated population, of whom 2,240 were under ten years of age, and of these vaccinated children 736 died.

In the Philippines, global public health measures were instituted when the United States began its occupation to establish a self-reliant government in the early 1900s. The incidence of smallpox steadily declined and the compulsory vaccine campaign was credited with this dramatic reduction. However, in the years 1917 to 1919, the Philippines experienced the worst epidemic of smallpox in the country's history with over 160,000 cases and over 70,000 deaths in a completely vaccinated population. Over 43,000 deaths from smallpox occurred in 1919 alone. The entire population of the Philippines at the time was only 11 million.

Vaccine failures of this magnitude may have several causes. The vaccine used could have been defective. During that period it was difficult to verify what the vaccine actually contained. The vaccine could have been contaminated with smallpox virus and actually caused epidemics. Or vaccine critics may have been correct in asserting that Jenner's cowpox vaccine, which is essentially the same vaccine used today, simply did not work to prevent smallpox.