In the United States, vaccines have greatly reduced or eliminated many infectious diseases that once routinely killed or harmed infants, children, and adults. However, the viruses and bacteria that cause these diseases still exist and you can still get these diseases if you aren't vaccinated.
Vaccines can lower your chance of getting certain diseases. Vaccines work with your body's natural defenses to help you safely develop immunity to disease, and this lowers your chances of getting these diseases and suffering from their complications
During the first few years of your child's life there are several vaccines they will need to receive to help provide protection against certain diseases. When your baby is born, his/her immune system is not fully developed which can put them at greater risk for infections. Vaccines reduce your child's risk of infection by working with their body's natural defenses to help safely develop immunity to disease.
While most vaccinations are administered during the first year or two of a person's life, that doesn't mean there aren't vaccinations we should receive as adults. Adults need to keep their vaccinations up to date because immunity from childhood vaccines can wear off over time. You may need other vaccines based on your age, health conditions, job, lifestyle, or travel habits.