Final answer:
Immunization against rabies can occur before or after exposure to the virus. Vaccines can stimulate active immunity in advance, and post-exposure prophylaxis with rabies vaccines and immune globulin can combat the virus following a bite from an infected animal. Rabies is now rare in humans in the U.S. due to effective vaccinations of domestic and wild animals.
Step-by-step explanation:
Immunization against rabies can occur before or after exposure to the pathogen. Before potential exposure, vaccines are used to develop an active immunity. If someone is bitten by a rabid animal, immediate post-exposure prophylaxis is necessary, which includes the administration of a series of rabies vaccines to prompt the immune system to fight off the virus. Additionally, a person may receive an injection of human rabies immune globulin to provide passive immunity, which contains antibodies that bind to and neutralize the rabies virus.
In the United States, rabies is relatively rare in humans due to widespread vaccination programs for domestic animals, and the use of oral rabies vaccines for wild animals. This approach, of vaccinating animals in areas where rabies is endemic, has proven effective in reducing the instances of rabies transmission to humans.
The concept of immunization is rooted in the fact that exposure to noninfectious antigens, like those in vaccines, produces a primary immune response without causing disease, granting immune memory. This immune memory ensures that if the individual is later exposed to the actual pathogen, the immune system responds more vigorously. Because this immune memory can fade over time, booster vaccinations may be required to sustain immunity.