Vaccines are important because they help protect individuals and communities from serious and sometimes deadly infectious diseases. Vaccines work by triggering the body's immune system to create a response to the disease, without causing the disease itself. This allows the immune system to recognize and fight the actual disease if it is encountered in the future. Vaccines have led to the elimination or near-elimination of numerous diseases, such as smallpox and polio. Vaccines also help to prevent the spread of contagious diseases, which can reduce the overall impact of an outbreak and protect vulnerable populations who may not be able to receive vaccines, such as infants or those with weakened immune systems.
