Vaccination

Immunity is a person's resistance to (or protection from) a disease. A person may be born with temporary protection from certain diseases, or a person may be protected after having an infection or vaccination. Immunity occurs because the body's immune system recognizes a foreign substance (such as a virus or bacteria) and sends antibodies (proteins made by the immune system) to destroy it.

Immunity may be temporary or permanent, depending on the nature of the disease, how the person became immune, and other factors. For instance, some vaccines give a person lifelong immunity against a disease and only have to be given one time. Others have to be given on a regular schedule (every 10 years, for example) because they do not provide permanent immunity. Partial immunity implies some degree of protection from a disease.

Vaccination helps you develop immunity. Vaccination (also called immunization) is the process of giving a person very small amounts of viruses or bacteria without causing them to get sick. Vaccines help the immune system know and remember different diseases so that it can stop them from causing illness or death in the future.

The American Academy of Pediatrics recommends that childhood immunizations start right after birth. Many are given during a baby's first 23 months. Booster shots (the later doses of any vaccines that need to be repeated over time) occur throughout life. 

Fewer immunizations are needed after age 6. But older children and teens need shots too (such as those for bacterial meningitis and for tetanus, diphtheria and whooping cough). Some shots are also given during adulthood (such as a tetanus shot).

It is important to keep a childhood vaccination record, including a list of any reactions to the vaccines. When you enroll your child in day care or school, you may need to show proof of immunizations. Your child may also need the record later in life for college, employment, or travel.

Learn more about childhood immunization.

The vaccines you need as an adult depend not only on your age, lifestyle, overall health, pregnancy status, and travel plans but also on who you are in close contact with and what vaccines you had as a child. Talk to your primary care provider about which vaccines you need. 

Common adult vaccines include:

• Flu
• COVID
• Pneumococcal
• Shingles
• Tetanus, diphtheria, and pertussis
• Human papillomavirus (HPV)

Learn more about adult vaccination.

Yes, vaccines undergo rigorous safety testing before they are approved for use. They are also constantly monitored for serious side effects after being introduced. Some vaccines cause mild, temporary side effects such as a sore arm or feeling tired for 2-3 days. That is normal.

Some parents are concerned about a link between autism and the shot for measles, mumps, and rubella. But studies have found no link between vaccines and autism.

Vaccines do not overload or weaken the immune system. It is safe for children and adults to receive several vaccines at a time.

Many vaccines require booster shots because immunity naturally decreases over time. A booster dose adds to the protection provided by the original shot(s) and helps your body maintain strong protection against infectious diseases. It's very important to stay up to date on all vaccines and booster shots recommended for your age group.