Common questions about vaccines

Vaccines protect you, your family, and your community from serious, preventable disease. Learn more about how vaccines can help prevent disease, and current vaccine recommendations.

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Why vaccination is important

Vaccination is important because it protects the person receiving the vaccine and the surrounding community.

The diseases vaccines prevent can be dangerous, or even deadly. Vaccines reduce your risk of infection by working with your body’s natural defenses to help safely develop immunity to disease.

How do vaccines work?

When germs, such as bacteria or viruses, invade the body, they attack and multiply. This invasion is called an infection, and the infection is what causes illness. The immune system then has to fight the infection. Once it fights off the infection, the body has a supply of cells that help recognize and fight that disease in the future. These supplies of cells are called antibodies.

Vaccines help develop immunity by imitating an infection, but this “imitation” infection does not cause illness. Instead it causes the immune system to develop the same response as it does to a real infection so the body can recognize and fight the vaccine-preventable disease in the future. Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever. Such minor symptoms are normal and should be expected as the body builds immunity.

What is herd immunity and how does it work?

Vaccination helps prevent the spread of disease, especially to those who are most vulnerable to serious complications (such as infants and young children, the elderly, and those with chronic conditions and weakened immune systems). This is a concept known as herd immunity. By protecting yourself, you also protect members of your community from the spread of vaccine-preventable diseases.

What are the current vaccine recommendations?

Every year, tens of thousands of Americans get sick from diseases that could be prevented by vaccines – some people are hospitalized, some even die. Vaccines are our best protection against these diseases. Vaccines are recommended for children, teens, and adults based on different factors like age, health conditions, lifestyle, jobs, and travel. CDC and other medical experts update vaccine recommendations every year based on the latest research and science.

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