Vaccination is the administration of antigenic material (the vaccine) to produce immunity to a disease. Vaccines can prevent or ameliorate the effects of infection by a pathogen. It is considered to be the most effective and cost-effective method of preventing infectious diseases. The material administrated can either be live, but weakened forms of pathogens such as bacteria or viruses, killed or inactivated forms of these pathogens, or purified material such as proteins.



The basic principle of vaccination is that a disease-causing agent is given to a person in a killed or weakened form (or in the form of proteins genetically engineered to look like a disease-causing agent), in order to stimulate the production of antibodies to fight off the disease.

Are vaccines safe?

Vaccines are generally quite safe. The protection provided by vaccines far outweighs the very small risk of serious problems. Vaccines have made many serious childhood diseases rare today. Talk to your family doctor if you have any questions.

Are there any reasons my child should not be vaccinated?

In some special situations, children shouldn't be vaccinated. For example, some vaccines shouldn't be given to children who have certain types of cancer or certain diseases, or who are taking drugs that lower the body's ability to resist infection. The MMR vaccine shouldn't be given to children who have a serious allergy to eggs.

If your child has had a serious reaction to the first shot in a series of shots, your family doctor will probably talk with you about the pros and cons of giving him or her rest of the shots in the series. Talk to your doctor if you have any questions about whether your child should receive a vaccine.

When should my child be vaccinated?

Recommendations about when to have your child vaccinated change from time to time. You can get a copy of the most current vaccination schedule on the World Wide Web from an organization such as the American Academy of Family Physicians or the American Academy of Pediatrics, or you can ask your family doctor. Vaccinations usually start when your child is 2 months old and most are finished by the time he or she is 6 years old.