explain how vaccines prevent infection
Vaccines work by stimulating your body's immune system to produce a response to a specific infectious agent, such as a virus or bacteria. This response helps your body recognize and fight off the infection if you come into contact with the actual pathogen in the future.
Vaccines are typically made from a weakened or inactivated form of the pathogen, parts of the pathogen (like proteins or sugars), or a similar but less harmful pathogen. When you receive a vaccine, your body recognizes the foreign substances in the vaccine as potentially harmful and mounts an immune response.
Here is a step-by-step explanation of how vaccines prevent infection:
1. Introduction of the pathogen: When you receive a vaccine, the weakened or inactivated pathogen or its components are introduced into your body. Your immune system recognizes these substances as foreign.
2. Recognition and response: Your immune system's specialized cells, known as antigen-presenting cells (APCs), digest the pathogen components and present small fragments, called antigens, on their surface. These antigens act as warning signals to other immune cells.
3. Activation of B cells: The antigens presented by APCs activate B cells, a type of white blood cell. B cells produce antibodies that recognize the specific antigens on the surface of the pathogen.
4. Antibody production: Activated B cells multiply and differentiate into plasma cells. Plasma cells secrete large amounts of antibodies, molecules that are specifically tailored to bind with and neutralize the antigens on the pathogen's surface.
5. Memory cell formation: Some of the activated B cells also become memory B cells. Memory B cells "remember" the specific antigen, allowing for a faster and stronger immune response if you are exposed to the same pathogen in the future.
6. Activation of T cells: Another type of white blood cell called T cells play a crucial role in the immune response. T cells recognize and eliminate infected cells or directly attack pathogens.
7. Immune system readiness: After receiving a vaccine, your immune system is primed and ready to respond quickly and effectively if you encounter the actual pathogen. The memory B cells and T cells remain in your body, providing long-term immunity.
By inducing an immune response without causing the actual disease, vaccines help to protect you from infection. If you do come into contact with the infectious agent later on, your immune system has a head start in recognizing and fighting it, eliminating or significantly reducing the severity of the infection.