Benefits of Immunization
Vaccines provide protection from serious illnesses. Vaccines can prevent a disease from occurring in the first place, rather than attempt to cure it after the fact.
Some people believe that naturally acquired immunity—immunity from having the disease itself—is better than the immunity provided by vaccines. However, natural infections can cause severe complications and be deadly. This is true even for diseases that most people consider mild, like chickenpox. It is impossible to predict who will get serious infections that may lead to hospitalization.
Vaccines, like any medication, can cause side effects. The most common side effects are mild. However, many vaccine-preventable disease symptoms can be serious, or even deadly. Although many of these diseases are rare in this country, they do circulate around the world and can be brought into the U.S., putting unvaccinated children at risk. Even with advances in health care, the diseases that vaccines prevent can still be very serious – and vaccination is the best way to prevent them
Benefits for Others
Vaccines protect not only yourself but also others around you. If your vaccine-primed immune system stops an illness before it starts, you will be contagious for a much shorter period of time, or perhaps not at all. Similarly, when other people are vaccinated, they are less likely to give the disease to you. Vaccines protect not only individuals but entire communities. That is why vaccines are vital to the public health goal of preventing diseases.
If a critical number of people within a community are vaccinated against a particular illness, the entire group becomes less likely to get the disease. This protection is called community, or herd, immunity. On the other hand, if too many people in a community do not get vaccinations, diseases can reappear. In 1989, low vaccination rates allowed a measles outbreak to occur in the United States. The outbreak resulted in more than 55,000 cases of measles and 136 measles-associated deaths.
Reference: Centers for Disease Control and Prevention