To avoid infection with Mycobacterium leprae, primary leprosy prevention comprises immunoprophylaxis, chemoprophylaxis, and public education. Immunoprophylaxis involves the administration of vaccines or other agents that stimulate the immune system to produce antibodies against M. leprae. Chemoprophylaxis is the use of drugs to prevent infection with M. leprae after exposure to the organism. Public education includes teaching people about leprosy and how to recognize signs of the disease. The only vaccine available for leprosy is the BCG vaccine. It reduces the risk of developing lepromatous (slow-growing) leprosy by more than 50 percent and dimorphic (between skin and nerve tissue) leprosy by almost 20 percent. It does not protect against tuberculoid (fast-growing) leprosy or nerve damage from leprosy. People who are not already immune compromised may be given the BCG vaccine during a visit to a clinic. It can also be given at other times but only once. The vaccination should be given in a clinic or hospital where a qualified physician is available to monitor its response to ensure there are no adverse effects. If you have not been vaccinated before, the process takes approximately 15 minutes.