CONTACT: BECKY SOGLIN
Iowa City IA 52242
(319) 335-6660; fax (319) 384-4638
Release: June 20, 2002
UI one of four institutions to take part in NIH smallpox vaccine study
The University of Iowa is one of four institutions nationwide selected to
participate in a smallpox vaccine study aimed at increasing current stocks
of the smallpox vaccine. The study is sponsored by the National Institute
of Allergy and Infectious Diseases, one of the institutes within 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 Jack Stapleton, M.D., professor in the
infectious diseases division of the UI Department of Internal Medicine and
director of the Helen C. Levitt Center for Viral Pathogenesis.
A total of 95 participants ages 18 to 32 years will be invited to take part
in the trial. Most people in the United Sates in that age group have never
been vaccinated against smallpox because common use of the vaccine ended in
1971, Stapleton said.
As a result, these individuals would be susceptible in the event of a biological
attack that used smallpox. Current smallpox vaccine stores are not sufficient
to provide inoculations to the entire U.S. population in the event that this
"The science of this study is to determine whether a smallpox vaccine
that has been stored for approximately 40 years still is effective and whether
it can effectively be used at a lower dose than originally planned. If a lower
dose is effective, the current vaccine preparation would be capable of vaccinating
more people," Stapleton said.
Earlier this year, the Centers for Disease Control and Prevention (CDC)
took its smallpox vaccine stock, known as Dryvax, which had been in storage
for decades and tested it in full-strength and diluted forms. The CDC determined
that the vaccine still worked in its original form and also was effective
in vaccinating people when diluted by the ratio of 1:10.
The UI study will help determine whether the Dryvax vaccine can effectively
inoculate people when diluted to a ratio even greater than 1:10 and whether
the Aventis smallpox vaccine stocks are also effective in full-strength usage
and at dilutions of 1:5 and 1:10.
"We will extend the study of Dryvax to see if additional dilutions
are possible," Stapleton said. "We also will see if the Aventis
vaccine has retained its potency at full dose and if it can be diluted like
the Dryvax and still be effective. At least in the test tube, the Aventis
vaccine appears to have retained its potency.
"There is a large stockpile of the Aventis vaccine in storage, and
if it can be diluted 1 to 10, there should be enough vaccine available to
vaccinate the entire U.S. population," 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 CDC.
Smallpox is spread among people by saliva and causes high fever, fatigue,
headaches and 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.
Stapleton 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
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," said Stapleton, who also is a researcher and staff physician at
the Veterans Affairs Medical Center in Iowa City. "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 at www.niaid.nih.gov/publications/bioterrorism.htm.
For additional smallpox information, visit the CDC at www.cdc.gov/nip/smallpox/default.htm
or the NIH at www.nlm.nih.gov/medlineplus/smallpox.html.
Smallpox-related images, some of which are in the public domain, are available
by clicking on "Smallpox images" at the CDC site www.bt.cdc.gov/Agent/Smallpox/Smallpox.asp.
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. Visit UI Health Care online at www.uihealthcare.com.