about Epidemiology & the department

Epidemiology academic information

Epidemiology faculty

Epidemilogy resources

sites of interest to Epidemiology professionals

Last Updated

11 Feb 2003

Source: Newsday, February 11, 2003

The Campaign Against Smallpox

The national initiative to vaccinate has generated many questions both from the public and health care experts

This story was reported and written by staff writers Earl Lane, Delthia Ricks and Jamie Talan.

President George W. Bush announced a sweeping program in December, calling for the vaccination of the military and 500,000 volunteers from hospitals and public health clinics around the country. The program, which started last month, expands in the summer, when vaccinations of 10 million first-responders nationwide begin. The administration hopes to develop a cadre of immunized medical and emergency workers in the event of a bioterrorist attack. As commander in chief of the armed forces, the president himself underwent vaccination in December. But federal officials acknowledged that the campaign was off to a slow start, with confusion about compensation issues, should the vaccine cause harm, and disagreement about whether the risk is justified. Last week, the director of the Centers for Disease Control and Prevention underscored the federal commitment to the program. "We want the state and local health jurisdictions to implement this program as fast as they can, but more importantly, as safely as they can," Dr. Julie Gerberding said. Between 100 and 200 medical professionals and emergency first-responders are to be inoculated in New York's first round of vaccinations this month. Here are questions and answers about the campaign, the disease and the vaccine:


Q. Is there any evidence of smallpox samples in hands of enemy nations?

A. Secretary of State Colin Powell told the United Nations last week there is evidence of biological weapons in the possession of the Iraqis. He did not say smallpox was one of those weapons, but top advisers to the Bush administration have long suspected that vials of smallpox may be among them. Smallpox was eradicated from the planet in an aggressive campaign more than 20 years ago. The last case in the United States occurred in 1949.

Q. Have vaccinations of medical workers begun?

A. Yes. As of last Tuesday, the Centers for Disease Control had received requests for vaccine kits from 42 states and four county health departments nationwide. All told, 256,100 vaccine doses have been ordered as of last week. Many states will receive multiple shipments. The first vaccinations of health care workers were performed Jan. 24 in Connecticut, the day the Homeland Security Act went into effect. As of Wednesday, 687 people in 16 states had been inoculated.

Q. Are experts in complete agreement about the program?

A. No. An Institute of Medicine advisory panel last month called for more time between the first and second phases of the program to give experts a sufficient period to assess volunteers' response to the vaccine. The 15-member panel of experts was convened by the institute at the request of the CDC. The Institute of Medicine is an arm of the National Academies and has a congressional mandate to answer critical questions in health care.

Q. Why are there concerns about the program?

A. The live-virus smallpox vaccine can cause side effects and, though rarely, death - from 1 to 2.7 deaths per million vaccinations. CDC officials say education is a key part of the campaign. The agency is providing information about the vaccine and the overall campaign to potential volunteers through state and county health departments as well as on its Web site:

Q. Who pays for the vaccination?

A. Vaccinations are free to volunteers. All supplies of smallpox vaccine, both those on hand and those being manufactured, are property of the federal government. Federal health officials have also given states $1.1 billion to help pay for their smallpox immunization programs. But state and local officials have warned they may have to siphon money from other programs to pay for those efforts.

Q. Is anyone liable for the illnesses or deaths that may occur in the campaign?

A. There is no compensation fund for volunteers who may be injured by the vaccine. This is an area of great debate among unions and professional organizations, such as the American Nurses Association, because it is not clear whether all private insurers will cover illnesses caused by vaccination. Also of concern is whether volunteers will be compensated while furloughed for vaccine-related complications. Organizations representing health care workers are asking that the entire program be halted until those questions are answered.

Q. Can volunteers sue the federal government?

A. Secretary of Health and Human Services Tommy G. Thompson said anyone suffering an adverse effect from the vaccine can sue the federal government under the Federal Tort Claims Act. But plaintiffs would have to prove negligence to receive compensation. This would be a difficult challenge if the vaccine was administered properly.

Q. What about worker's compensation programs?

A. Dr. Julie Gerberding of the CDC said, "We are encouraging the prospective volunteers to know how their workers comp programs, their health benefits or their other insurance plans cover adverse events related to the vaccine." For uninsured or unemployed persons who insist on the vaccine, compensation for injury is uncertain.

Q. Can all health care workers volunteer to be vaccinated?

A. No. They must be 32 or older and have been vaccinated in the past. Volunteers must not be pregnant, have eczema or a history of the skin disorder, or a diagnosis of HIV. Vaccinated parents of young children need to carefully follow vaccination site-care instructions to avoid exposing their children to the virus. Federal health officials are seeking previously vaccinated volunteers because vaccination in the past indicates these people would not have had an adverse reaction to the vaccine.

Q. How are patients of health workers protected immediately after their doctors and nurses have been vaccinated?

A. Because the virus in the vaccine can be transmitted to others, health care workers are to wear bandages and be checked by a medical expert in the program until their vaccination "takes." That varies but usually occurs in two weeks. However, some health care workers who are in close contact with immune-compromised patients may have to be furloughed until their vaccination takes.


Q. Why is it called smallpox?

A. The name developed about 500 years ago to distinguish the smaller lesions of smallpox from the larger lesions of syphilis, which was then called greatpox.

Q. What is the history of smallpox?

A. It is estimated that smallpox infected hundreds of millions of people over 10,000 years, and may have killed tens of millions. In 1967, when the World Health Organization mounted its unprecedented eradication campaign, 15 million people were contracting smallpox annually and 2 million were dying.

Q. How was smallpox controlled?

A. The World Health Organization sponsored a global eradication program using vaccination, detection, investigation and containment of cases as its strategy. The last naturally transmitted case occurred in Somalia in 1977. The next year, two people became infected during a laboratory accident in Britain in 1978. Two years later, the victory over smallpox was declared.

Q. Smallpox is caused by a virus. What is a virus?

A. Generally speaking, a virus is a submicroscopic scrap of nucleic acid - DNA or RNA - enclosed in a wrapper of protein. This infectious package can become active only inside a living cell. Viruses function by insinuating themselves into the DNA of their hosts and commandeering the host's genes, a process that leads to disease. Once inside human DNA, viral interlopers manufacture countless more viruses, continuing the process of subverting host DNA.

Q. What is variola?

A. Variola is the virus that causes smallpox, and it is one of the most dangerous of the known pox viruses, which infect a variety of species.

Q. How does the disease develop?

A. The disease usually begins with an extreme fever, chills and overwhelming malaise. Next comes a rash in the mouth and throat that can develop into open sores, then a skin eruption that progresses from rash to bumps to pustules to scabs, which eventually fall off.

Q. How contagious is smallpox?

A. Generally, direct and fairly prolonged face-to-face contact is required. Additionally, smallpox can be spread by direct contact with infected bodily fluids or contaminated objects such as bedding or clothing. CDC officials last year, quoting a German study, said airborne transmission is possible from as far away as 30 feet. Humans are the only natural hosts of variola. Smallpox is not known to be transmitted by insects or animals.

Q. Is it contagious before symptoms show?

A. A person with smallpox is sometimes contagious with onset of fever but becomes most contagious with the onset of rash. At this stage, the infected person is usually very sick and not able to move around in the community. The infected person is contagious until the last smallpox scab falls off.

Q. How dangerous is smallpox?

A. Historically, 30 percent of unvaccinated people who become infected died. Complications can include encephalitis, pneumonia, arthritis, secondary skin infections, keratitis and corneal ulceration, which leads to blindness.

Q. Is there any treatment?

A. Smallpox can be prevented through vaccination. There is no proven treatment for smallpox, but research on new antiviral agents is ongoing. Early results from laboratory studies suggest that the drug cidofovir may fight the virus, and animal studies are being done to better understand the drug's ability to treat the disease. Patients can benefit from supportive therapy (e.g., intravenous fluids, medicine to control fever or pain) and antibiotics for secondary bacterial infections.


Q. How was the vaccine developed?

A. In the late 1700s, British physician Edward Jenner noticed that milkmaids who came in contact with the cowpox virus - evidenced by lesions on their hands - did not contract smallpox. In 1798, he announced development of his vaccine after a clinical trial in which he administered cowpox particles from milkmaids' lesions to a young boy, James Phipps. Jenner also exposed Phipps to scabby material from smallpox lesions and found that the boy did not get the disease. That discovery marked the birth of the smallpox vaccine, the first effective vaccine in Western medicine.

Q. What is vaccinia?

A. Vaccinia is the live virus in the smallpox vaccine. Over time, the cowpox virus used in vaccine production was modified, resulting in a virus dubbed vaccinia. The vaccinia strain used in the United States was cultivated by the New York City Board of Health in the early 20th century.

Americans were last vaccinated in 1972. Since then, only those scientists who handled the virus have received the vaccine.

Q. How is the vaccine given?

A. The smallpox vaccine is not given with a hypodermic needle. The vaccine is given using a bifurcated (two- pronged) needle dipped into the vaccine solution. When removed, the needle retains a droplet of the vaccine. The needle is then used to prick the skin 12 to 15 times in the upper arm.

If the vaccination is successful, a red and itchy bump develops in three or four days. In the first week after vaccination, the bump becomes a large blister, fills with pus and begins to drain. During week two, 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 may have a stronger "take" than those who are being revaccinated.

Q. If someone is exposed to smallpox, is it too late to get a vaccination?

A. Vaccination within three days of exposure will completely prevent or significantly modify smallpox in the vast majority of people. Vaccination four to seven days after exposure likely offers some protection from disease or may modify the severity of disease.

Q. How long does a smallpox vaccination last?

A. Past experience indicates that the first dose of the vaccine offers protection from smallpox for three to five years, with decreasing immunity thereafter. If a person is vaccinated again later, immunity lasts longer.

Q. Is it possible to get smallpox from the vaccination?

A. No. The smallpox vaccine does not contain smallpox virus and cannot spread or cause smallpox. However, because the vaccine contains vaccinia, it is possible those with weakened immune systems or other predisposing conditions could become infected with it. Because the virus is live, it can spread to other parts of the body or to other people from the vaccine site. This can be prevented through proper care (hand washing and careful disposal of used bandages).

Q. Is it possible to get vaccinia, the virus in the vaccine, from someone who has recently been vaccinated?

A. Yes. Vaccinia is spread by touching a vaccination site before it has healed or by touching bandages or clothing that have become contaminated with live virus from the vaccination site. Vaccinia is not spread through airborne contagion. The vaccinia virus may cause rash, fever, and head and body aches.

Q. How many smallpox vaccines are there?

A. In the United States, there are three brands, all based on the New York City Board of Health strain of vaccinia. Dryvax, manufactured by Wyeth Laboratories Inc., is a freeze-dried vaccine that is reconstituted with a fluid compound called a diluent. Another type of vaccine, a "liquid," has been held in freezers at the Pennsylvania division of Aventis-Pasteur Inc., a French vaccine maker, since 1958. The doses are considered as a backup in the federal stockpile and will be used if needed. A British pharmaceutical company, Acambis Plc, is manufacturing a newer type of vaccine made from modern cell-culture techniques. The seed virus in all three is the same.

Q. Are those the only vaccines?

A. No. There are several other types of smallpox vaccines made from other strains of vaccinia. Among them are the Lister strain, also known as the Elstree vaccine strain, which was developed in Britain. The Lister strain was used along with Dryvax in the global smallpox eradication program of the 1960s and '70s. Currently, Lister is being administered in the Israeli smallpox vaccination program. Additionally, there are the Bern, Ankara and Soviet smallpox vaccines, among others, all of which use various strains of vaccinia. The Soviet vaccine uses the New York City Board of Health's vaccinia virus as its seed strain.

Q. What are some of the complications associated with vaccination?

A. Smallpox vaccination can cause between 1 and 2.7 deaths and 15 adverse reactions in every 1 million people who receive it. Deaths can occur from vaccine-caused encephalitis or from eczema vaccinatum, a condition that can develop in people with eczema in which virus-filled pustules erupt all over the body. The condition is complicated by a high fever and, ultimately, organ shutdown. Statistics on vaccine complications are derived from data compiled by Dr. J. Michael Lane and colleagues of the Centers for Disease Control in the 1960s, based on epidemiologic studies conducted when smallpox vaccinations were routinely administered in the United States.

Q. Do side effects differ from one type of vaccine to another?

A. No. However, the severity of side effects is believed to be less pronounced with some types of vaccines. The Lister vaccine, for example, has a lower rate of side effects compared with vaccines based on the New York City Board of Health vaccinia strain. However, evidence of immunity against the disease is better with the American inoculation.

Q. Are there any eye conditions that would preclude vaccination?

A. People who wear contact lenses or touch their eyes frequently can get the smallpox vaccine, but they must be especially careful to follow instructions for care of the vaccination site. Frequent and thorough hand washing will minimize the chance of contact spread of the vaccinia virus. Anyone with eye diseases or other conditions (recent LASIK surgery, for example) that require the use of corticosteroid drops in the eye should wait until they no longer require such treatment before getting vaccinated.

Q. Is there a treatment in the event of an adverse reaction to vaccinia?

A. Yes. Vaccinia immune globulin, or VIG, can be administered by intramuscular injection. VIG is used to treat serious vaccine reactions, but not to treat smallpox. It is composed of antibodies contained in blood plasma of people vaccinated against smallpox.

Q. Have there been any clinical trials of the vaccines?

A. Yes. A major trial completed last year demonstrated that Dryvax can be diluted and still confer immunity. Volunteers in that study ranged in age between 18 and 32 and had never been vaccinated against smallpox. Several trials are under way now; one is examining how well the vaccine works in people vaccinated in the past. Participants are between 32 and 75.

Q. Why have diluted vaccines been tested?

A. Standard doses were established more than a half-century ago, when doctors were focused on limiting spread of the disease. Standard dose levels were reached through consensus among physicians and not through scientific testing. The new clinical trials are designed to establish the best dose to confer immunity with a minimal amount of live-virus exposure.

Q. Has there been a clinical trial involving children?

A. No. A trial designed to test the vaccine in a small number of children is on hold pending a decision by Health and Human Services Secretary Tommy Thompson. The prospects of such a trial, which had been planned for two clinical testing sites (Ohio and California), generated controversy, and the Health and Human Services Department late last year solicited public opinion. The majority of responders opposed testing children.