A panel of smallpox experts has suggested that the widespread use of the smallpox vaccine--which contains vaccinia, a live virus related to smallpox--may lead to many more cases of vaccine-related side effects, which can include brain damage and death, particularly among those people with compromised immune systems and infants. In a report published in the October 16th issue of the Journal of American Medical Association, experts including Dr John M. Neff, of the Children's Hospital and Regional Medical Center in Seattle, Wash., say a tightly controlled and limited vaccination program that includes comprehensive screening and education to exclude those people who are at risk of dangerous side effects, as well as people in contact with high-risk individuals, may result in only a fractional number of serious exposures. However, Neff adds, the program currently undergoing review by the government is far too extensive a plan to contain the exposure and risks--particularly since immunization stopped in 1972, making anyone under 30 years old and newly vaccinated a risk to others for weeks afterward. The makeup of today's population is different too, Neff observed, citing the prevalence of HIV, more organ-transplants, and other illnesses that can compromise immune systems.