Rabies vaccination is a series of shots given over a period of 2 weeks after a possible exposure to rabies. Rabies vaccines contain inactivated virus particles that increase the body's immune response, which in turn helps destroy the rabies virus.

Three rabies vaccines have been approved for use in the United States; all are considered equally effective and equally safe. The vaccines are:

• Human diploid cell vaccine (HDCV).
• Rabies vaccine, adsorbed (RVA).
• Purified chick embryo cell culture (PCEC).

A rabies vaccine (HDCV, RVA, or PCEC) is given:

• In the form of a shot, usually in the upper arm muscle for adults and in the thigh for children. (Shots are never given in the buttocks because they are not very effective.)
• Four times over the span of 2 weeks. The first shot should be given as soon as possible after suspected exposure. Additional shots are given on days 3, 7, and 14 after exposure. A shot of rabies immunoglobulin usually is also given right after exposure.

Local reactions, such as pain, itching, and swelling at the site of the shot, have been reported after vaccination with each of the three vaccines available in the U.S. Systemic reactions, such as headache, nausea, abdominal pain, and muscle aches, are less common.

Newer rabies vaccines used today are not as painful and do not require as many shots as the older vaccines.