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Release: Oct. 24, 2002

Photo: Patricia Winokur, left; Jack Stapleton

UI selected to participate in follow-up NIH smallpox study

The University of Iowa is one of three institutions nationwide selected to participate in a follow-up study aimed at increasing current stocks of the smallpox vaccine. The study is sponsored by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health (NIH).

The UI portion of the investigation will take place at the UI General Clinical Research Center and will be led by Patricia Winokur, M.D., and Jack Stapleton, M.D., faculty members in the infectious diseases division of the UI department of internal medicine, and members of the Helen C. Levitt Center for Viral Pathogenesis. Winokur and Stapleton are also researchers and staff physicians at the Veterans Affairs Medical Center in Iowa City.

A total of 148 participants, ages 18 to 32, will be invited to take part in the trial. Most people in the United Sates in this age group have never been vaccinated against smallpox because common use of the vaccine ended in 1971, Winokur said.

As a result, these individuals would be susceptible in the event of a biological attack that used smallpox. Smallpox is thought to be one of the most dangerous diseases that could be used in bioterrorism. Current estimates are that 120 million Americans are susceptible to smallpox, and given the 30 percent mortality rate found with smallpox, the effect of a terrorist attack could be profound.

"This study follows our study completed this past summer. We will be determining the effectiveness of different dilutions of a smallpox vaccine that was stored for approximately 40 years. The previous study strongly suggests that we can dilute this vaccine, and this new study will more precisely determine the amount of vaccine available," Stapleton said.

"In addition to determining vaccine effectiveness, we plan to study the effects of vaccination on human gene expression and inflammation as part of the new study," he added.

A smallpox vaccine can reduce or prevent illness if given to a person within four days after they have been exposed to the disease, according to the Centers for Disease Control and Prevention

(CDC). Smallpox is spread among people by saliva and causes high fever, fatigue, headaches, backaches and a rash that can eventually lead to scarring. Although the majority of people recover from the disease, nearly 30 percent of infected individuals die.

Winokur said the vaccine can have side effects that include soreness in the arm, and approximately 10 to 15 percent of individuals who receive the vaccine may feel ill enough to miss work for a day or two. The vaccine is not smallpox, but a related virus called "vaccinia." Infection with vaccinia results in a mild infection that gives a person protection against smallpox.

After the last natural case of smallpox was documented in 1977, the World Health Organization declared the disease eradicated in 1980 and urged that people no longer be inoculated against it. People vaccinated for smallpox before 1972, when routine vaccinations stopped, may no longer have immunity against the disease. The U.S. military continued to routinely provide the smallpox vaccine to its troops until a few years ago.

At the federal level, experts are discussing smallpox vaccination policies that range from providing vaccinations after a biological attack or providing them to people proactively, including as a requirement for health care workers.

"There is consideration of whether or not we should immunize everyone now, or target specific groups likely to be needed for immunization, like first-responders and health care workers," Stapleton said. "These are important policy decisions that are currently under review."

For more information about National Institute of Allergy and Infectious Diseases smallpox research, visit the institute online at For additional smallpox information, visit the CDC online at or the NIH at

Smallpox-related images, some of which are in the public domain, are available by clicking on "Smallpox images" at the CDC Web site

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide.