Smallpox, a scourge estimated to have killed 500 million people worldwide, was officially declared eradicated in 1979, according to the World Health Organization. There are risks associated with the smallpox vaccination, even though significant side effects are rare, and death is very rare, Winkenwerder said. The topic of his talk was bioterror, but the unsettling show-and-tell wasn't focused on the threat of smallpox: it addressed the serious risks of the vaccine meant to prevent it. The most serious side effects of smallpox vaccine include progressive vaccinia, postvaccinial central nervous system disease, and eczema vaccinatum. The smallpox vaccine contains a live virus called vaccinia. Smallpox Vaccination Side Effects "Smallpox Vaccination Side Effects" is also availiable in PDF format. A vaccine can prevent smallpox, but the risk of the vaccine's side effects is too high to justify routine vaccination for people at low risk of exposure to the smallpox virus. Most people experience normal,typically mild reactions to the vaccine, which indicate that it is beginning to work.Some people may experience reactions that may require medical attention. Careful monitoring of smallpox vaccinations given over recent months has suggested that the vaccine may have caused side effects on the heart. Health care professionals administer the vaccine by dipping a pronged piece of metal into the vaccine and then pricking the skin. Products & Services Book: Mayo Clinic Family Health Book, 5th Edition The smallpox vaccine prevents smallpox. "These are things the American public needs to understand," said the speaker, Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases. But others are more fearful of a smallpox attack. Many public health specialists who worry about vaccine side-effects say that only a few people should be vaccinated until there is an outbreak. "Our experience is that it is possible to reduce those risks associated with the vaccine," he said. The vaccine has uncommon side effects that may be fatal, including infection of the heart and brain with the vaccinia strain. The smallpox vaccine prevents smallpox.For most people, it is safe and effective. Apr 29, 2005 (CIDRAP News) – In a recent study, some laboratory and public health workers who received smallpox shots reported several side effects that have not shown up in other studies, including joint and abdominal pain, backache, and breathing difficulty. Scars like the smallpox vaccine scar form due to the body’s natural healing process. Severe side effects following administration of the smallpox vaccine do occur but are relatively uncommon: In a small number of people, the smallpox vaccine can cause swelling of the heart or the tissue that surrounds it, leading to chest pain or pressure, fast or irregular heartbeat, or breathing problems. For most people, it is safe and effective. When the skin is injured (like it is with the smallpox vaccine), the body rapidly responds to repair the tissue.