They're trying to find out if the vaccine could be stretched far enough to cover everyone if it's needed.

Close to 150 Iowans are taking part in the research at the University of Iowa.

"They rub the vaccine on the area and they poke you 15 times; I would liken it to being poked by a ball-point pen. It's annoying but not painful," study participant Karen Cowdery said.

"I just got a little bit of soreness in my arm and then there's a little bit of a burning sensation for a little while, and then I got a little dizzyishness, kind of like just a mild flu symptom," study participant Chris Thompson said.

The University of Iowa is just one of three centers around the country testing the vaccine.

The smallpox-vaccine researchers are testing part of the nation's decades-old limited stockpile. The National Institutes of Health wants to know if diluting the vaccine will still protect people against smallpox.

U of I Researcher Dr. Patricia Winokur said, "We have stored lots of the vaccine. If we can dilute them we will have enough vaccine to vaccinate the entire country. From preliminary studies we have this summer we do have enough vaccine at this point in time to vaccinate the U.S. if that were required."

Researchers said the study should help reassure the government that if there's a need, there's enough vaccine for everyone who needs it.

Previous Stories:

• December 4, 2002: Iowa Creates Smallpox Vaccination Plan
• October 19, 2001: Iowa Doctor Addresses Smallpox Concerns