While planning to manufacture enough smallpox vaccine for every American, the government is hunting the medication necessary to treat severe, even life-threatening, side effects from the vaccine. 

Smallpox vaccine is made from a live virus called vaccinia that itself can cause serious infections that result in large open sores all over the body. This vaccinia infection can be fatal, particularly in people with weak immune systems, such as organ transplant recipients and cancer patients, and those with the skin disease eczema.

Medication called vaccinia immune globulin, or VIG, can treat the side effect, and thus VIG would have to be on hand if anyone were inoculated with smallpox vaccine. It is obtained from the blood of people recently vaccinated, and routine smallpox inoculations ended in 1972, although military personnel and certain laboratory workers have been vaccinated more recently.

The nation's remaining stock of VIG is stored in a federal stockpile. The Food and Drug Administration has cast doubt on whether all of that VIG still is usable. A spokesman said Monday it could be used only as an experimental medication under strict scrutiny.

To supplement the remaining stocks, the government is hunting new sources of VIG, Dr. Anthony Fauci of the National Institutes of Health said Monday.

First, companies that make regular immune globulin — a sterile solution of immune system antibodies used to treat more than half a dozen various diseases — are being asked to check whether this regular IG may harbor vaccinia antibodies. That's possible if regular IG was taken from someone in the military who had a smallpox vaccination as recently as the early 1990s, Fauci said.

Also, companies now negotiating with the government to make up to 300 million doses of smallpox vaccine would have to do safety studies of their product in people before the FDA would approve it. As soon as people were vaccinated in such studies, VIG could be taken from them, Fauci said.

And if, in the worst case, smallpox vaccine were needed immediately because of a bioterror attack, the people being vaccinated would be a self-propogating source of VIG, he said.

The government had 15.4 million doses of smallpox vaccine in a federal stockpile, and another 54 million doses are to be manufactured by late summer. Negotiations with other manufacturers for the full 300 million doses are under way, and Fauci said the hope is for the full supply to be on hand by the end of next year.

At the same time, the NIH is financing research leading to creation of a safer smallpox vaccine, which would be made with a killed virus and would not be as risky to use.