Rabies is a severe viral disease that affects the nervous system of mammals, including humans, and is almost always fatal once symptoms appear. The rabies vaccine plays a significant role in preventing this disease, both before and after potential exposure.
The Rabies Vaccine: An Inactivated Virus
The rabies vaccine is classified as an inactivated, or “killed,” virus vaccine, meaning it contains rabies virus particles that have been treated to render them unable to replicate or cause disease. These viruses are processed to inactivate them while preserving their structural integrity. This allows the body’s immune system to recognize the virus and mount a protective response without experiencing the illness itself. The two main types of inactivated cell culture rabies vaccines currently available for human use are human diploid cell vaccine (HDCV) and purified chick embryo cell vaccine (PCEC). This type of vaccine has an established safety profile and efficacy in stimulating immunity.
Preventing Rabies: Pre-Exposure Vaccination
Pre-exposure prophylaxis (PrEP) involves administering the rabies vaccine to individuals before any potential exposure to the virus. This vaccination is recommended for people at higher risk of contact with rabid animals or the rabies virus, often due to their occupation, hobbies, or travel plans. Such groups include veterinarians, animal handlers, laboratory workers, and travelers visiting areas where rabies is common and medical access might be limited. The standard pre-exposure vaccination schedule typically involves two doses given on days 0 and 7.
This proactive vaccination simplifies post-exposure treatment, reducing the number of vaccine doses needed after an exposure and eliminating the need for rabies immune globulin. While PrEP does not remove the necessity for medical attention following a potential exposure, it offers protection, particularly if treatment is delayed or exposure goes unrecognized. For individuals with ongoing risk, a one-time antibody titer check or a booster dose may be recommended years after the initial series to maintain protection.
Responding to Exposure: Post-Exposure Treatment
Post-exposure prophylaxis (PEP) is an emergency treatment administered after a suspected rabies exposure to prevent the virus from reaching the central nervous system. This regimen includes immediate wound care, the administration of human rabies immune globulin (HRIG), and a series of rabies vaccine doses. Prompt and thorough cleansing of the wound with soap and water for at least 15 minutes is the initial step, as it physically removes the virus.
For individuals who have not been previously vaccinated against rabies, HRIG is infiltrated into and around the wound site to provide immediate, passive immunity. HRIG contains pre-formed antibodies that neutralize the virus until the body can produce its own antibodies in response to the vaccine. Concurrently, a series of rabies vaccine doses are administered, typically four doses on days 0, 3, 7, and 14, to stimulate the body’s active, long-lasting immune response. The first vaccine dose is given on the same day as HRIG, but at a different anatomical site to prevent interference with the immune globulin.
Rabies Vaccines for Animal Health
Rabies vaccination in animals is a strategy for controlling the disease and safeguarding human populations. Domestic animals, particularly dogs and cats, are routinely vaccinated against rabies, often as a legal requirement in many regions. This widespread animal vaccination reduces the risk of rabies transmission to humans.
Inactivated rabies virus vaccines, similar to those used in humans, are commonly administered to animals via injection. These vaccines are effective in providing immunity and preventing the spread of the virus among animal populations. Beyond domestic pets, oral rabies vaccines (ORV) containing modified live viruses are also utilized in wildlife management programs to control rabies in reservoir species like foxes, raccoons, and skunks.