NA/military 12/18/2002 Jahi Chikwendiu/TWP A doctor marks th

NA/military 12/18/2002 Jahi Chikwendiu/TWP A doctor marks the spot where he will administer the smallpox vaccination to a military person at the Walter Reed Army Medical Center, Washington, DC. The spot is marked so that doctors can closely monitor the skin's reaction to the vaccination immediately after it's given. Smallpox vaccine is made from a virus called vaccinia, which is similar to smallpox but less harmful. The vaccine does not actually contain the smallpox virus. (Photo by Jahi Chikwendiu/The The Washington Post via Getty Images)