Vaccine Basics

Vaccines help prevent people from getting sick. They also help reduce the spread of disease to others and prevent epidemics. There are many kinds of vaccines. Each vaccine is made up of parts of weakened or killed bacteria or viruses of a specific disease. After you have a vaccine, your body's immune system makes antibodies to fight the disease. If you are exposed to the same disease in the future, the antibodies kill the bacteria or viruses before they have a chance to make you sick.

If you get a vaccine, it may not completely prevent you from getting a disease, but it makes it much less likely. If you get a disease even after you have been vaccinated, it usually will be only a mild case.

Vaccines are usually given by shot (injection). Some are given by mouth as a pill or liquid, or by a spray (aerosol) into the nose. Vaccines are also called immunizations.

Immunization Schedules

In the United States, the Centers for Disease Control and Prevention (CDC) and other national organizations advise people about which immunizations they should get and when. Immunization schedules are for healthy children, teens, and adults as well as for people who have health problems and other circumstances, including pregnancy, asthma, or diabetes. To see or print a list of recommended immunizations based on your age, past immunization history, and other factors, see the CDC immunization schedules at www.cdc.gov/vaccines/schedules/index.html.

Children and teens in the United States usually need proof that all their immunizations are up-to-date before they can start school or day care. Also, students of any age entering college usually need to have a written record showing that their immunizations are up-to-date.

For more information on when to get vaccines, see the topic Immunizations.

The CDC may recommend certain immunizations for people who are going to travel to a foreign country. For more information, see the topic Travel Health.

Vaccine Information

The Centers for Disease Control and Prevention (CDC) creates Vaccine Information Statements (VISs), which have details about most vaccines given in the United States. The VISs are updated when needed.

The information in these statements does not change often. Each VIS explains why to get the vaccine, the risks from the vaccine, what to do if you or your child has a moderate or severe reaction, and more.

If you have any questions about a vaccine, see the CDC website www.cdc.gov/vaccines, or talk to your doctor.

There are Vaccine Information Statements for:

• Adenovirus(What is a PDF document?)
• Anthrax(What is a PDF document?)
• Chickenpox (Varicella)(What is a PDF document?)
• Diphtheria/Tetanus/Pertussis (DTaP)(What is a PDF document?)
• Flu (influenza) nasal spray(What is a PDF document?)
• Flu shot(What is a PDF document?)
• Haemophilus Influenzae Type b (Hib)(What is a PDF document?)
• Hepatitis A(What is a PDF document?)
• Hepatitis B(What is a PDF document?)
• Human Papillomavirus (HPV) – Cervarix(What is a PDF document?)
• Human Papillomavirus (HPV) – Gardasil(What is a PDF document?)
• Japanese Encephalitis – Ixiaro(What is a PDF document?)
• Measles/Mumps/Rubella (MMR)(What is a PDF document?)
• Measles/Mumps/Rubella/Varicella (MMRV)(What is a PDF document?)
• Meningococcal(What is a PDF document?)
• Pneumococcal Conjugate (PCV)(What is a PDF document?)
• Pneumococcal Polysaccharide (PPSV)(What is a PDF document?)
• Polio (IPV)(What is a PDF document?)
• Rabies(What is a PDF document?)
• Rotavirus(What is a PDF document?)
• Shingles(What is a PDF document?)
• Smallpox (Vaccinia)(What is a PDF document?)
• Tetanus/Diphtheria (Td) and Tetanus/Diphtheria/Pertussis (Tdap)(What is a PDF document?)
• Typhoid(What is a PDF document?)
• Yellow Fever(What is a PDF document?)