How safe is smallpox vaccine?

How safe is
smallpox vaccine?

By Dave Duffy

Dave Duffy

Issue #81 • May/June, 2003

At the start of 2003 the United States began the vaccination against smallpox of half a million health care workers so America can respond to a possible terrorist smallpox attack. It is only the beginning of a plan to vaccinate millions of Americans, beginning with health care workers and the military. The fear is that terrorists, and possibly Iraq, have acquired the deadly and disfiguring smallpox virus and intend to use it against us.

Many people may think no sane human being would consider using a disease like smallpox as a weapon. After all, even the diabolical Nazis of World War II possessed nerve agents and biological weapons but refrained from using them, even as they were bombed into obliteration during the last months of the war. But think again. According to many muslim terrorists, it is God’s will that America the Infidel be destroyed.

It is not an unheard of rationale. In at least one documented case during the conquest of the Americas, a British colonel deliberately distributed smallpox infected blankets to Indians, which led to an epidemic among them. And during the Spanish conquest of the Aztecs, which coincided with another smallpox epidemic among the Indians, a Spanish priest wrote in his diary: “Thank you heavenly Father for sending this plague to destroy our enemies.” There is even some evidence that the British tried to spread smallpox among the Colonists, and during America’s own Civil War, there is an undocumented report of a Confederate supplying unsuspecting Union soldiers with smallpox infected blankets.

Man, historically, has always justified his most reprehensible actions, and muslim crusaders will have no problem justifying a smallpox attack against us.

What is smallpox?

Smallpox is a highly contagious disease caused by the variola virus, which is an orthopox virus in the same family as monkeypox, mousepox, camelpox, rabbitpox, and cowpox. Cowpox is used to make smallpox vaccine, called vaccinia.

Man with smallpox. Smallpox has been eliminated thanks to vaccines.
Man with smallpox. Smallpox has been eliminated thanks to vaccines.

Smallpox no longer exists as a naturally occurring disease, having been wiped out by the World Health Organization’s (WHO) worldwide smallpox eradication program in the 1960s and 70s. But for thousands of years, since it first appeared about 12,000 years ago in settlements in northeast Africa, smallpox had been one of the most feared of plagues, killing hundreds of millions of people, decimating whole civilizations, and not even sparing kings. The mummy of the great Egyptian pharaoh Ramses V, who died in 1156 BC, bears the distinctive smallpox scarring on his face, and the Roman Emperor Marcus Aurelius was killed by smallpox in a plague that killed millions in the Roman Empire about 180 AD. In the last decades of the 18th century smallpox killed 400,000 Europeans a year, including four reigning monarchs, and in the 20th century the disease killed an estimated 300-500 million people. By comparison, wars in the 20th century, which was history’s bloodiest century for warfare, killed 111 million people.

Historically smallpox has killed 30% of its victims, although that number has been higher in very susceptible populations. The New World populations of Indians had never experienced smallpox so were very susceptible. Between 1580 and 1620 smallpox reduced the Aztec population of Mexico from about 20 million to less than 2 million, after Spanish conquistadors had inadvertently introduced it there, and smallpox is the main suspect in reducing the overall North American Indian population from about 100 million at the time of Columbus’s arrival to about 10 million a mere 50 years later.

How is it spread?

Smallpox is normally spread through direct contact with an infected person, and transmission of the virus occurs when a person inhales a virus-containing airborne droplet of an infected person’s saliva. But it can also spread from contact with an infected person’s fluids, clothing, and bedding. It is not spread by animals or insects.

The virus is very stable and will survive for months in an infected person’s clothing and bedding, even dried in the dust in his sick room, in the form of viral material from the smallpox pustules or from the pustules’ crusted scabs. These are much less infectious than the airborne droplets, but infected clothing and bed linens have historically been a source of smallpox outbreaks in Europe.

Smallpox victims are infectious with the onset of rash, which occurs 2-4 days after the onset of fever, which occurs 10-14 days after initial exposure to the disease. Victims are most infectious during the initial week (after development of rash) when they develop lesions in the mucous membranes of the mouth, tongue, larynx, pharynx, and upper part of the esophagus. The victim sheds part of the lesions in airborne water droplets during this period. As the lesions develop on the skin, the person remains infectious to a declining degree until the lesions turn to scabs and the scabs fall off.

Types of smallpox

There are three types of smallpox, ordinary, flat, and hemorrhagic, that can occur in unvaccinated persons, plus a fourth type, modified, that can occur in previously vaccinated people.

Smallpox lesions at day 17 of rash on a 5-year-old convalescing
Smallpox lesions at day 17 of rash on a 5-year-old convalescing

1) Ordinary smallpox (Variola major): This is by far the most common type. Once exposed to ordinary smallpox, it takes from 7-17 days for symptoms to appear. (The average incubation time is 12-14 days.) Then symptoms are flu-like, progressing from a high fever, cough, and fatigue to headache, backache, and other body aches with occasional vomiting and disorientation. After two to four days of these symptoms, the fever peaks and begins to decline, ushering in a rash that develops into hard painful lesions. The lesions appear first on the mucous membranes and pharynx, then on the face, forearms, and hands. Within a day or two, the trunk and lower limbs, including the palms of the hands and soles of the feet, also become involved with the rash. The rash lasts for about two weeks and becomes most pronounced on the face, forearms, and lower legs. At the end of 14 days the lesions, which by now have developed into hard raised painful sores called pustules, begin to dry up and crust over. By about day 19 the scabs begin falling off, with the scabs on the palms and soles falling off last. The resulting scars, which are most pronounced on the face, are the result of the destruction of the underlying sebaceous glands.

Thirty percent of victims will die, usually from toxemia leading to respiratory or heart failure. Death, if it occurs, is usually in the second week. Some victims will also become blind, generally as a result of opportunistic bacterial infections.

Ordinary smallpox can sometimes be confused with chickenpox. With chickenpox, however, the rash is more uniformly distributed on the body, with no rash on the palms or soles.

2) Flat type smallpox: This is very rare and is believed associated with a deficient immune system. It occurs more frequently in children and is characterized by intense toxemia. The lesions remain soft and velvety, and never progress to the pustular stage. Although the majority of cases are fatal, survivors typically are not scarred.

3) Hemorrhagic smallpox: This is also rare and associated with people with a compromised immune system. It occurs more frequently in adults. The virus multiplies in the spleen and bone marrow and leads to the inability of the blood to clot, resulting in spontaneous bleeding from spots on the skin and from the mucous membranes. The illness includes a shortened incubation period followed by severe high fever, headache, and stomach pain. These victims are highly infectious, and death occurs in the fifth or sixth day after incubation, before lesions typical of ordinary smallpox have a chance to develop.

4) Modified type smallpox: This type usually appears in previously vaccinated people. The incubation period, followed by headache and body pains, are similar to ordinary smallpox. The rash, however, develops without the presence of fever, and lesions are fewer, more superficial, and progress more quickly, with crusting accomplished within 10 days. These victims are infectious, but not nearly as infectious as victims with ordinary smallpox.

History of smallpox vaccine

The decision by President Bush to resume smallpox vaccination marks the first time in U.S. history that a nationwide public health preventive measure has been put into operation to defend against attack with disease.

The vaccine for smallpox is called vaccinia. It is a live virus derived from cowpox, a relative of smallpox but much milder.

The ring method of stopping a smallpox outbreak

    At present the Centers for Disease Control’s (CDC) plan to contain a smallpox attack includes widespread voluntary vaccination but, if necessary, forced quarantine of infected individuals and mandatory tracing and vaccination of anyone who may have come in contact with them.
    They will employ the “ring” method to control an epidemic, namely vaccinate everyone who has had contact with an infected person, then vaccinate the ring of people who have had contact with the first set of contacts. It’s the method used so successfully in the 1960s and ’70s to finally eradicate smallpox.
    Keep in mind that for up to four days after exposure to smallpox, vaccination will either keep a person from catching the disease or lessen its severity.

The earliest form of smallpox inoculation was developed in China and India about 1000 B.C. Called variolation, it consisted of taking the pus from the pox of an infected person and inoculating a healthy person with it. A mild form of the virus developed and granted the person lifelong immunity. The practice spread to Europe and the New World in the 1700s.

In Britain in the mid 1700s, cowpox was a disease that primarily affected milkmaids, and it was noticed that they became resistant to smallpox after they recovered. In 1774, a British farmer from Dorset inoculated his family with material taken from the udders of a cow with cowpox, thereby granting his family immunity from smallpox. And in 1796 a British surgeon extracted fluid from the pustule of a cowpox victim and injected it into a healthy child, conferring smallpox protection on him. By 1800 smallpox vaccination campaigns using cowpox began throughout Europe.

Modern science has now learned that cowpox is a virus that primarily infects rodents and only occasionally infects cows. It exists primarily in Europe.

The World Health Organization’s (WHO) worldwide smallpox vaccination program, designed to eradicate the disease, began in 1967 and ended in 1980 when smallpox was officially declared eradicated, making it the only human disease ever eradicated. The last reported case of smallpox was in Somalia in 1971, and in the United States the last reported case was in 1949. Vaccinations for U.S. civilians stopped in 1972, and U.S. military smallpox vaccinations stopped in 1990. Vaccine production discontinued in the U.S. in 1982.

When eradicated, the world community agreed to keep two samples of the disease in laboratory repositories in the United States at the CDC in Atlanta, and in the Soviet Union at the Russian State Research Center of Virology and Biotechnology in Koltsovo, Novosibirsk, which is in central Siberia.

Vaccination has begun again under a renewed threat of the return of the disease. It is feared that hostile states such as Iraq and North Korea, and possibly terrorists like Al Qaida, now have the smallpox virus and may use it against us. The threat has become more credible since the terrorist attacks in New York on Sept. 11, 2001 and the subsequent anthrax attack by an unknown person or persons shortly thereafter.

Types of vaccines and availability

There is currently enough smallpox vaccine to vaccinate all 288.6 million residents of the U.S. This includes about 75 million doses of the 1970s era Dryvax vaccine and about 300 million doses of the 1950s era Wetvax vaccine. The old vaccine has been stored cold and has been tested every two or three years to test its potency. Some of the vaccine has been diluted up to five times to make it go further, but tests indicate it is still potent.

Close-up of the skin reaction at a smallpox vaccination site
Close-up of the skin reaction at a smallpox vaccination site

The U.S. has ordered 209 million more doses of a more modern smallpox vaccine from Acambis Inc., a Cambridge, Massachusetts based company, and it should be ready for use in early 2004. It hasn’t been fully tested but initial tests indicate it will be safe and effective. The FDA has not yet licensed enough of any of the vaccine for general public use, but it will be made available to the public without licensing in the event of a smallpox epidemic emergency. There is no definitive way to test the potency and safety of the new vaccine in the absence of an outbreak of smallpox.


Successful vaccination produces total immunity to smallpox. Once vaccinated, it takes approximately 7-10 days to achieve protection. However, if you are vaccinated within 3-4 days of initial exposure to smallpox, you may receive total protection from the disease, or at least protection against severe illness. The vaccine is then good for about 5-10 years (no one knows for sure). If you are later revaccinated it is believed immunity from smallpox lasts even longer, although how long no one knows. There is no danger in being vaccinated multiple times. Dr. D.A. Henderson, the director for the Center for Civilian Bio-Defense Studies at Johns Hopkins University, who in 1966 was the WHO director overseeing the global eradication of smallpox, says he has been vaccinated between 25 and 100 times. The live vaccinia virus vaccine, he says, must grow in your skin to produce immunity to smallpox. If you are already sufficiently immune, the vaccine simply does not grow in the skin.

The severity of lesions from smallpox can vary greatly, either naturally or because vaccination years before has given a person partial, but not complete, protection. With nearly complete protection from vaccine, few lesions will appear, but even if a person was vaccinated many years before, lesions may be far less and more superficial than for a person who was never vaccinated. In this case a person could get a mild case of smallpox, with an accompanying mild rash. He will not die and may not even get very sick, but he may be contagious, capable of passing along fullblown smallpox to another person.

Adverse reactions to vaccine

Smallpox vaccine has a higher adverse reaction rate than any of the modern vaccines generally given. Based on the statistics of the 1960s and 70s smallpox eradication program, as many as 50% of people being vaccinated will have some sort of reaction from the vaccine, ranging from a sore, swollen arm and swollen glands to flu-like symptoms. In a study of adult primary vaccinees, it was determined that 36% became sufficiently ill to miss school, work, or a recreational activity, or to have trouble sleeping. In another study 17% had fever of at least 100 degrees Fahrenheit within two weeks of vaccination, 7% had a fever of 100 degrees or more, and 1.4% had a fever of 102 degrees or more.

One or two of every million people who get the vaccine for the first time will die from it, 15 to 50 will have life threatening reactions including eczema vaccinatum, progressive vaccinia (vaccinia necrosum), and post vaccinal encephalitis, and approximately 1,000 will have serious reactions including a toxic or allergic reaction at the vaccine site and spread of the vaccinia virus to other parts of the body. If all 130 million Americans never vaccinated got vaccinated, about 250 would die and 2,000 would have life-threatening reactions. This does not include people with AIDS, who could be very severely affected.

The data showed that the death rate and adverse reaction rate for those being revaccinated was cut by two-thirds, but still if all 158 million Americans who were previously vaccinated were to get revaccinated, it is expected that 40 would die and 800 would have life threatening reactions. Again, this does not take into account people with AIDS or other immune system problems.

Vaccinia Immune Globulin

A major difficulty in treating adverse reactions to the vaccine is that in past years bad reactions were treated with vaccinia immune globulin (VIG), which is serum derived from people who recovered from infection with the vaccine virus. Due to the absence of smallpox vaccinations for 30 plus years, the supply of VIG is now about 700 doses, which is enough for anticipated adverse reactions if only 6 million people get vaccinated. Additional doses of VIG are being produced.

Compare these adverse reaction rates with a more modern vaccine such as the measles/mumps/rubella vaccine, which has experienced 11 adverse reactions and no deaths among the 30 million people vaccinated in the last 12 years. The newer smallpox vaccine, the 209 million doses still under final testing, is expected to have fewer adverse reactions than the older smallpox vaccine.

The death rate and adverse reaction rate may be much higher today because the U.S. population, or any modern population, is highly susceptible to smallpox because it has been so long (1949) since the disease has been present in the U.S. and because it has been so long (1972) since vaccinations were discontinued. Health officials expect the death and adverse reaction rate to be much lower among that older 58% of our population that has been vaccinated in the past, even though for most of them it has been the distant past, and they expect the adverse reactions in the younger 42% of the population never vaccinated at all to be significantly higher.

The most frequent complications of smallpox vaccination

From previous data, adverse reactions from vaccination occurred most often in people receiving their first dose of the vaccine, and among children under the age of 5. Following are the most frequent complications.

Inadvertent inoculation at other sites. This accounted for half of all complications of vaccination. Occurring in 1 of every 2,000 primary inoculations, it generally resulted from the hand touching the vaccination site, then touching another part of the body, thereby transferring the vaccination. The most frequent inadvertent inoculations occurred on the mouth, eyelid, rectum, genitals, nose, and face. It generally resolves itself.

Generalized vaccinia. This occurred in 1 of every 5,000 primary vaccinations, and it is the result of blood-borne dissemination of vaccinia virus. It generally resolves itself unless there is an underlying condition involving an immune deficiency. Vaccinia Immune Globulin (VIG) (See Sidebar) can be used to successfully treat cases involving the eye.

Eczema vaccinatum. This occurred in 1 out of every 26,000 primary vaccinations, and it occurred in people who had current or healed eczema or other chronic skin problems. It typically covers the area affected by the skin condition, and it is usually mild and resolves itself. But on occasion it can be severe or fatal. VIG is used to successfully treat serious cases.

Progressive vaccinia (vaccinia necrosum). This is rare, severe, and often fatal, and it is caused by the vaccine site’s failure to heal. It occurs in people with underlying immune disorders and can occur after primary vaccination or revaccination. VIG is used to treat it, but with varying success.

Post-vaccination encephalitis. Also rare, this occurred in 1 out of 300,000 cases of primary vaccinations, with most occurring in children under the age of one year. It is characterized by fever, headache, vomiting, and sometimes convulsions, paralysis, or coma. Symptoms manifest themselves 8-15 days after vaccination. About 15-25% of cases died and another 25% had permanent neurological damage. VIG is not effective.

Sufficient voluntary vaccination means high U.S. “herd immunity”

A survey of Americans in late 2002 indicated that more than half of Americans would be willing to get vaccinated. But the survey was taken before there was widespread understanding of the risks involved.

At present the vaccine is being made available only to the military and the 10 million or so emergency health care “first responders” such as police, firefighters, ambulance crews, EMTs, hospital emergency care workers, etc. When the vaccine is made available to the public, it will be on a voluntary basis. People will simply have to weigh the risk of having an adverse reaction against the risk that we will be attacked with smallpox. The idea of making it widely available on a volunteer basis is to build up “herd immunity.” Since a certain number of people will opt for the vaccine, the nation’s “herd immunity” will increase. Then if we are attacked with smallpox, the increased herd immunity will lessen the severity of any resulting epidemic.

Secondary infection of the cornea in a 12-year-old male
Secondary infection of the cornea in a 12-year-old male

In the event of a smallpox epidemic, the Centers for Disease Control and Prevention (CDC) recommends everyone get vaccinated, even if you have AIDS. The risk of getting smallpox far outweighs the risk of having an adverse reaction from the vaccine. The vaccine can be taken for up to four days after exposure to smallpox and still be effective in either preventing the disease or greatly lessening its effects.

Although the CDC says smallpox vaccination will be on a voluntary basis, it is anticipated that in the event of an attack and subsequent smallpox epidemic, smallpox vaccinations will likely become mandatory in affected areas. Quarantines and isolation will definitely be mandatory. Based on historical experience, there is no other way to contain an epidemic.

You won’t be able to sue

If you are one of the unlucky ones who does get an adverse reaction to the vaccine, you won’t be able to sue anyone. The Homeland Security Act has a provision protecting vaccine makers and healthcare providers from such suits. People injured may sue in federal court, but they will have to prove negligence, which will be just about impossible because the vaccine is advertised as coming with risks. The liability protection for vaccine makers was deemed necessary in light of the fact the U.S. needed a new vaccine fast and no company was willing to make one unless they got liability protection.

Genetically-altered smallpox

All of the above may become moot if we are attacked with a genetically-altered form of of the smallpox virus. No one knows if such a virus exists, but Soviet defector Dr. Ken Alibek, the former chief scientist and first deputy director of Biopreparat, the former Soviet Union’s secret offensive bioweapons program, says the Soviet Union was working on such a virus when he left their program in 1992. Dr Alibek is now a U.S. citizen and chief scientist at a private company in the U.S. that specializes in researching and developing medical defenses against biological weapons.

How vaccine is given

The vaccine is given by dipping a bifurcated (two-pronged) needle into the vaccine, then puncturing the skin of the upper arm 15 times in a few seconds. The puncturing of the skin is not deep. If the vaccination is successful, within three to four days a red, itchy bump will form, then develop into a large blister that fills with pus and drains. In two weeks the blister dries up and a scab forms. The scab falls off in the third week and leaves a small scar. To prevent the vaccinia virus in the vaccine from spreading to other people or other parts of your body, the vaccine site should be covered with a bandage. Children especially should be watched so they do not touch the site, then inadvertently touch, say, their eye.

Also, both NBC News and the New York Times have reported that another former Russian virologist, the late Dr. Nelja Maltseva, may have given the genetically-altered strain of smallpox to Iraq.

Researchers have tested their ability to alter a related orthopox virus. They inserted the gene interleukin-4 into the mousepox virus, then exposed mice previously vaccinated against mousepox to the genetically altered virus. As they feared, many of the mice died. They are not sure if a genetically altered smallpox virus would defeat the smallpox vaccine, but it is definitely a fear.

The Iraq connection

Before they were thrown out in 1998, U.N. inspectors had discovered that Iraq had experimented with camelpox, another relative of smallpox, and one fear is that camelpox, which ordinarily does not harm humans, might be modified and used as a biological weapon. The smallpox vaccine, however, protects against all orthopox viruses, including camelpox. During their inspections in Iraq, U.N. inspectors found a freeze-drier labeled smallpox. Also, after the first Gulf War, 69 Iraqi prisoners of war were blood tested and were found to have built up immunity to smallpox, indicating prior vaccination against the disease. The obvious question is why?

Genetically engineered vaccines and anti-viral agents

U.S. scientists meanwhile are working on a genetically engineered vaccine that will be more effective with fewer side effects than old vaccines. They are also working on anti-viral agents that could, for the first time in history, effectively treat a person already infected with smallpox. No one knows if these efforts will be successful any time soon, but early laboratory studies suggest the drug cidofovir may be effective. Tests with animals are ongoing and being monitored by the CDC and NIH. There are 3500 doses of cidofovir on hand at present, which is enough to handle anticipated reactions if 15 million people are vaccinated. It will be administered under an investigational new drug protocol. Otherwise, there is no treatment beyond intravenous fluids and medicines to control pain and secondary infections.


For up to date information on the vaccine situation, you can call the CDC hotline: English: 888-246-2675;

Spanish: 888-246-2857 or send them an email: On the internet you can find lots of information on smallpox and the smallpox vaccine, as well as on other biological and chemical threats, at the following sites:,,,,,,

People who should not get vaccinated

Eczema, dermatitis. People who have had or now have atopic dermatitis or eczema should not get the vaccine unless they are exposed to smallpox. As many as 40 million Americans, or up to 15% of the population, have had or currently have eczema, which puts them at higher risk for a potentially fatal skin infection called eczema vaccinatum. The risk is particularly great for children, who have experienced a threefold increase in eczema since smallpox vaccination ended three decades ago. In a study from the 1970s, 123 people out of one million vaccinated people got eczema vaccinatum, most of them children. In another study in Europe, 6 percent of people infected with eczema vaccinatum died from it. Running the numbers, if the 40 million Americans suspected of having had or currently having eczema were to get the vaccine, the death toll among them would be 295.

AIDS, other immune deficiency disorders. People who have a suppressed immune system, such as people who have had transplants or who have cancer, leukemia, lymphoma, or people with HIV and AIDS, are high risk groups. AIDS was not a known disease when vaccinations were given 30 years ago, so the severity of reaction for people with AIDS is not clear. Side effects can include brain swelling and extensive toxicity. Of particular concern to health authorities are the 100,000 to 350,000 Americans who have AIDS but who don’t know it. Also, if you are taking immune suppressive medications such as corticosteroids, or if you are undergoing radiation, you should not be vaccinated.

Pregnant women, children. Pregnant women should not be vaccinated, nor should they be vaccinated if they plan to get pregnant within one month of vaccination. Infants should also not get the vaccine.

The current recommendation that infants not be vaccinated is in sharp contrast to the smallpox vaccination programs of the 1960s and 70s, when most of the vaccinations were given to children under the age of 1. Now, children under the age of one year are considered at increased risk for vaccine-caused brain infection. Children have been omitted from all of the current studies involving smallpox vaccines. Because children are more prone to touching the vaccination site, then touching other parts of their bodies such as their eyes, or even touching other children, the vaccination site should be covered with a special extra sticky bandage.

Also, if you have any of the following conditions you should not get the vaccine until you have completely healed: burns, shingles, impetigo, herpes, severe acne or psoriasis, and chickenpox.

Since the vaccinia vaccine is a live virus and can accidentally spread to others causing inadvertent vaccination, those people living with any of the above at-risk people should not be vaccinated. A vaccinated person is infectious until the vaccination site scabs over. A vaccinated person could spread the vaccinia virus by touching the vaccination site, then touching another person. In the 60s and 70s it was common for this to happen among young siblings.

In all, about 50 million Americans should not get the vaccine, either because they have one of the conditions mentioned above or because they live with someone who does.


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