Although the virus causing smallpox was deemed eradicated worldwide through vaccination in 1980, the current global climate has caused concern in public health arenas that the virus could be used in a bioterrorist attack, infecting large portions of the population. Smallpox is a serious disease that kills about a third of those who contract it and has potentially serious consequences for those who survive the illness, such as encephalitis, corneal ulcerations, and blindness. Now the Food and Drug Administration (FDA) has approved a new drug, the first, for treatment of smallpox.

According to the Centers for Disease Control and Prevention (CDC), there are only two locations where the variola virus, responsible for smallpox, is officially stored: at CDC headquarters in Atlanta, and in the State Research Center of Virology and Biotechnology VECTOR, also known as the Vector Institute, in Koltsovo, Novosibirsk, Russia. Both locations are under the supervision of the World Health Organization, but public health scientists and government antiterrorist organizations are concerned that the virus may be stored elsewhere. The approval of tecovirimat (TPOXX) is an effort to thwart smallpox's effects if the virus is used as a weapon.

Vaccination against smallpox is effective if one has not been exposed to the virus, although protection is not lifelong. The likelihood that vaccination will protect against acquisition of smallpox decreases after exposure. The CDC has stored enough smallpox vaccine to vaccinate everyone in the United States, but once smallpox develops, vaccination is not helpful. Those who were vaccinated before 1972, the year routine administration of the smallpox vaccine was discontinued in the United States, may also be at risk if their immunity has waned.

Tecovirimat inhibits the activity of the orthopoxvirus VP37 protein, ultimately preventing dissemination of the virus to additional cells. The FDA approved tecovirimat on the basis of animal studies, which are used for drug approval when it would be unethical to use human subjects in clinical trials. Drug safety trials were conducted with 359 healthy human subjects who were given tecovirimat and monitored for adverse effects. The most common were headache, nausea, and abdominal pain.

Nurses should carefully read the drug's labeling for information on dosing, administration, and possible drug interactions so they can provide appropriate patient education in the event of a national emergency.

To read the FDA's news release on the approval of tecovirimat, go to http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm613496.htm.