Smallpox Vaccine

Definition: A live VACCINIA VIRUS vaccine of calf lymph or chick embryo origin, used for immunization against smallpox. It is now recommended only for laboratory workers exposed to smallpox virus. Certain countries continue to vaccinate those in the military service. Complications that result from smallpox vaccination include vaccinia, secondary bacterial infections, and encephalomyelitis. (Dorland, 28th ed)

The Smallpox Vaccine

The smallpox vaccine helps the body develop immunity to smallpox. The vaccine is made from a virus called vaccinia which is a “pox”-type virus related to smallpox. The smallpox vaccine contains the “live” vaccinia virus—not dead virus like many other vaccines. For that reason, the vaccination site must be cared for carefully to prevent the virus from spreading. Also, the vaccine can have side effects (see the section “Smallpox Vaccine Safety” in this fact sheet). The vaccine does not contain the smallpox virus and cannot give you smallpox.

Currently, the United States has a big enough stockpile of smallpox vaccine to vaccinate everyone in the United States in the event of a smallpox emergency.

Length of Protection

Smallpox vaccination provides high level immunity for 3 to 5 years and decreasing immunity thereafter. If a person is vaccinated again later, immunity lasts even longer. Historically, the vaccine has been effective in preventing smallpox infection in 95% of those vaccinated. In addition, the vaccine was proven to prevent or substantially lessen infection when given within a few days of exposure. It is important to note, however, that at the time when the smallpox vaccine was used to eradicate the disease, testing was not as advanced or precise as it is today, so there may still be things to learn about the vaccine and its effectiveness and length of protection.

Receiving the Vaccine

The smallpox vaccine is not given with a hypodermic needle. It is not a shot as most people have experienced. The vaccine is given using a bifurcated (two-pronged) needle that is dipped into the vaccine solution. When removed, the needle retains a droplet of the vaccine. The needle is used to prick the skin a number of times in a few seconds. The pricking is not deep, but it will cause a sore spot and one or two droplets of blood to form. The vaccine usually is given in the upper arm.

If the vaccination is successful, a red and itchy bump develops at the vaccine site in three or four days. In the first week, the bump becomes a large blister, fills with pus, and begins to drain. During the second week, the blister begins to dry up and a scab forms. The scab falls off in the third week, leaving a small scar. People who are being vaccinated for the first time have a stronger reaction than those who are being revaccinated. The following pictures show the progression of the site where the vaccine is given.

Post-Vaccination Care

After vaccination, it is important to follow care instructions for the site of the vaccine. Because the virus is live, it can spread to other parts of the body, or to other people. The vaccinia virus (the live virus in the smallpox vaccine) may cause rash, fever, and head and body aches. In certain groups of people (see the section “Smallpox Vaccine Safety” in this fact sheet), complications from the vaccinia virus can be severe.
Benefit of Vaccine Following Exposure

Vaccination within 3 days of exposure will prevent or significantly lessen the severity of smallpox symptoms in the vast majority of people. Vaccination 4 to 7 days after exposure likely offers some protection from disease or may modify the severity of disease.

Smallpox Vaccine Safety

The smallpox vaccine is the best protection you can get if you are exposed to the smallpox virus. Anyone directly exposed to smallpox, regardless of health status, would be offered the smallpox vaccine because the risks associated with smallpox disease are far greater than those posed by the vaccine.

There are side effects and risks associated with the smallpox vaccine. Most people experience normal, usually mild reactions that include a sore arm, fever, and body aches. However, other people experience reactions ranging from serious to life-threatening. People most likely to have serious side effects are: people who have had, even once, skin conditions (especially eczema or atopic dermatitis) and people with weakened immune systems, such as those who have received a transplant, are HIV positive, are receiving treatment for cancer ( Small Lung Cancer ), or are currently taking medications (like steroids) that suppress the immune system. In addition, pregnant women should not get the vaccine because of the risk it poses to the fetus. Women who are breastfeeding should not get the vaccine. Children younger than 12 months of age should not get the vaccine. Also, the Advisory Committee on Immunization Practices (ACIP) advises against non-emergency use of smallpox vaccine in children younger than 18 years of age. In addition, those allergic to the vaccine or any of its components should not receive the vaccine. Also, people who have been diagnosed by a doctor as having a heart condition with or without symptoms, including conditions such as previous myocardial infarction (heart attack), angina (chest pain caused by lack of blood flow to the heart), congestive heart failure, and cardiomyopathy (heart muscle becomes inflamed and doesn’t work as well as it should), stroke or transient ischemic attack (a “mini-stroke” that produces stroke-like symptoms but not lasting damage), chest pain or shortness of breath with activity (such as walking up stairs), or other heart conditions being treated by a doctor should not get the vaccine at this time. (Heart disease may be a temporary exclusion and may change as more information is gathered.) Also, individuals who have 3 or more of the following risk factors should not get the vaccine at this time: high blood pressure diagnosed by a doctor; high blood cholesterol diagnosed by a doctor; diabetes or high blood sugar diagnosed by a doctor; a first degree relative (for example, mother, father, brother or sister) with a heart condition before the age of 50; and/or, currently a cigarette smoker. (These may be temporary exclusions and may change as more information is gathered.)

In the past, about 1,000 people for every 1 million people vaccinated for the first time experienced reactions that, while not life-threatening, were serious. These reactions included a toxic or allergic reaction at the site of the vaccination (erythema multiforme), spread of the vaccinia virus to other parts of the body and to other individuals (inadvertent inoculation), and spread of the vaccinia virus to other parts of the body through the blood (generalized vaccinia). These types of reactions may require medical attention. In the past, between 14 and 52 people out of every 1 million people vaccinated for the first time experienced potentially life-threatening reactions to the vaccine. Based on past experience, it is estimated that 1 or 2 people in 1 million who receive the vaccine may die as a result. Careful screening of potential vaccine recipients is essential to ensure that those at increased risk do not receive the vaccine.

Smallpox Vaccine Availability

Routine smallpox vaccination among the American public stopped in 1972 after the disease was eradicated in the United States. Until recently, the U.S. government provided the vaccine only to a few hundred scientists and medical professionals working with smallpox and similar viruses in a research setting.

After the events of September and October, 2001, however, the U.S. government took further actions to improve its level of preparedness against terrorism. One of many such measures—designed specifically to prepare for an intentional release of the smallpox virus—included updating and releasing a smallpox response plan. In addition, the U.S. government has enough vaccine to vaccinate every person in the United States in the event of a smallpox emergency.

Jonas Salk

When Dr. Jonas Salk envisioned the idea of the Salk Institute for Biological Studies, it was with the idea of creating a vibrant, intellectual community, dedicated to pursuing the kinds of scientific achievements that had made him an international figure only five years before.

Thus a monument to the conquest of polio faithful to the facts would consist of not one man in a white lab coat but two of them glaring at each other. Both Drs. Jonas Salk and Albert Sabin could and did make convincing cases for themselves and pretty good ones against each other too. But since the public usually prefers one hero to two, and since Salk did get there first, he got the monument.

Jonas Salk was born in New York to proud Russian and Jewish immigrant parents. Though the family was materially poor and lacked formal education, they urged their children to work and study hard. Jonas Salk was the first sibling to enter the City College of New York to study Law, but fate intervened and he entered medical school instead of getting a law degree at the New York University.

Scientists, microbiologists worked hard to find an antidote, and finally their efforts and hard work paid off. On April 12, 1955 an official announcement was made that Dr. Jonas Salk has finally developed a vaccine that will once and for all eradicate polio. Dr. Jonas Salk became an overnight sensation not only in the United States but worldwide.

But who is Dr. Jonas Salk?

Jonas Salk, while still in medical school, was invited to do some research on the recently discovered influenza virus. Eager to learn, Salk succeeded in his research by depriving the virus the ability to infect and in so doing giving immunity to the illness as well. Thus in 1938, together with microbiologist Thomas Francis Jr., Salk developed the first vaccine on influenza and was used extensively by the Armed Forces in World War II. This became the foundation of his research on polio later on.

After completing medical school and his internship, he went back to the study of influenza, the flu virus. In 1947, Jonas Salk accepted residency at the Medical School of the University of Pittsburgh and worked with the National Foundation for Infantile Paralysis. It was here that he devoted 8 years of his life working to develop the polio vaccine. In 1952 his vaccine was developed; he and his family including his staff and volunteers were first inoculated to test its effectiveness.

The vaccine proved successful as everybody who received the test vaccine started producing anti-bodies against the virus so that nobody else became inflicted with polio and no side effect was observed. Jonas Salk published the results in the Journal of the American Medical Association the following year and a nationwide testing was made. It was during this time that worst polio outbreak happened involving 57,628 cases. It was Salk's former mentor Thomas Francis Jr. that helped and directed the mass vaccination of schoolchildren.

The success of the vaccination put Jonas Salk's fame forward and endeared himself to the public when he refused to patent the vaccine and the accompanying financial remuneration. Dr. Jonas Salk in his statement "merely wished to see the vaccine disseminated as widely as possible". The March of Dimes, a non-government organization hoping to boost publicity and raise donation to fund the vaccination programs praised the achievements of Salk to the point of offending his colleagues.

In 1963 he founded the Jonas Salk Institute for Biological Studies, a center devoted solely for medical and scientific research. His last years were devoted to finding a vaccine against AIDS. Dr. Jonas Salk died on June 23, 1995. He was 80 years old.

Jonas Salk liked to go down to the racetrack on occasion and place a wager or two on the ponies. But, he didn't stop there. According to unconfirmed reports, Jonas Salk like to sneak back into the stables behind the racetrack and actually spank the horses on their behinds. No one knows why he like to do this, but on more than one occasion he was spotted coming back into the stands with a horseshoe imprint upon his forehead.