What are vaccinations (vaccines)?
Vaccines are a way of getting your body ready to fight off certain infections. They don't fight infections after you're sick, like medicines do. Instead, vaccines help you avoid getting sick from certain infections.
Vaccines are sometimes called "immunizations," because vaccines teach your immune system Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more how to fight off certain diseases. If you have been protected against a disease by a vaccine, you are said to be "immune" to the disease.
Each vaccine works to prevent only one type of infection. For example, the flu vaccine only helps prevent the flu. And you may need to get a vaccine several times for it to be fully effective. Because vaccines are usually given by shot (injection), several vaccines are often combined into one shot so that you need fewer shots.
Doctors give babies and children vaccines based on a standard schedule
Doctors created the schedule based on the age children become at risk for different infections
Not following the schedule and getting shots late put your child at risk of getting a serious infection
In the United States, the Centers for Disease Control and Prevention provides up-to-date vaccination schedules and other useful information, available here:
Vaccines for Your Children: Find out which vaccines are recommended for your child based on their age
Do vaccines work?
Yes, vaccines lower the risk that your child will get an infection. Children who don’t get vaccines are more likely to get sick or die from certain infections than children who get vaccines. However, no vaccine works 100% of the time. A few children who've gotten vaccines for certain infections still get sick from those infections.
In the past, thousands of children died every year because of diseases that are now preventable by vaccines. Hundreds of thousands became seriously ill. Because of vaccines:
One deadly disease, smallpox, has been completely eliminated
Other serious diseases such as polio Polio Polio is a viral infection that can affect the nerves that control your muscles. Polio spreads when people eat infected food or water or touch an infected surface and then touch their mouth... read more , diphtheria Diphtheria Diphtheria is a contagious, sometimes fatal infection of the upper respiratory tract caused by the gram-positive, rod-shaped bacteria (see figure ) Corynebacterium diphtheriae. Some types... read more
, and tetanus Tetanus Tetanus results from a toxin produced by the anaerobic bacteria Clostridium tetani. The toxin makes muscles contract involuntarily and become rigid. Tetanus usually develops after a wound... read more now almost never happen in the United States Some common diseases are much less frequent, such as measles Measles Measles is a viral infection. It used to be very common in children in the United States. Measles is now rare in the United States because it's prevented by routine childhood vaccines. In parts... read more
, whooping cough (pertussis Pertussis Pertussis is a highly contagious infection caused by the gram-negative bacteria Bordetella pertussis, which results in fits of coughing that usually end in a prolonged, high-pitched,... read more ), and mumps Mumps Mumps is a contagious viral infection that causes painful enlargement of the salivary glands. The infection may also affect the testes, brain, and pancreas, especially in adolescents and adults... read more 
If infections are rare, why should my child get vaccines?
Many infections that vaccines can prevent still happen in the United States and are still common in other parts of the world. They can spread very quickly among children who haven't gotten vaccines. For example, measles Measles Measles is a viral infection. It used to be very common in children in the United States. Measles is now rare in the United States because it's prevented by routine childhood vaccines. In parts... read more outbreaks still occur in the United States. These outbreaks occur among children who have not received the measles vaccine. This is why it's important for all children to get vaccines.
What diseases can be prevented by vaccines?
Vaccines are available for the infections listed below that can affect children. Many are very contagious, which means they can spread easily and quickly to other people. That means that when your child receives a vaccine it helps protect other people too.
Chickenpox
COVID-19
Diphtheria
Haemophilus influenzae type b (which can cause meningitis and pneumonia)
Hepatitis A
Hepatitis B
Human papillomavirus (which can cause cancer of the cervix in girls and genital warts in girls and boys)
Influenza (the "flu")
Measles
Meningococcal infection (which can cause meningitis)
Mumps
Pertussis (whooping cough)
Pneumococcal infections (which can cause ear infections, sinus infections, pneumonia, and meningitis)
Polio
Rotavirus
Rubella (German measles)
Tetanus
Are vaccines safe?
Yes, vaccines are considered to be very safe. A few children develop side effects, but the side effects are rarely serious. And the diseases vaccines prevent are more dangerous to your child than the side effects of the vaccines.
Before a vaccine can be used, it’s tested for safety
Often, the side effects are minor, such as pain where the shot was given, a rash, or a mild fever
Very rarely, vaccine side effects are more serious
If your child has any problems after getting a vaccine, tell your child’s doctor right away
Will vaccines give my child autism?
No, there is no known link between vaccines and autism.
Doctors from across the world have done many studies to look for a connection between vaccines and autism and didn’t find one
Children who get vaccines are no more likely to get autism than are children who don’t get vaccines
