Vaccination Health Article

Definition

Vaccination is the use of vaccines to produce immunity to specific diseases.

Purpose

Many diseases that once caused widespread illness, disability, and death now can be prevented through the use of vaccines. Vaccines are medicines that contain weakened or dead bacteria, viruses, or pollen antigens. When a person takes a vaccine, his or her immune system responds by producing antibodies—substances that weaken or destroy disease-causing organisms. When the person is later exposed to live bacteria or viruses of the same kind that were in the vaccine, the antibodies prevent those organisms from making the person sick. In other words, the person becomes immune to the disease the organisms normally cause. The process of building up immunity by taking a vaccine is called immunization.

Vaccines are used in several ways. Some, such as the rabies vaccine, are given only when a person is likely to have been exposed to the virus that causes the disease, such as through a dog bite, for example. Others are given to travelers planning to visit countries where certain diseases are common. Vaccines such as the influenza vaccine, or "flu shot," are given mainly to specific groups of people—older adults and others whose health is at high risk if they develop influenza or its complications. Then, there are vaccines that are given to almost everyone, such as the one that prevents diphtheria.

Children routinely have a series of vaccinations that begin at birth. The American Academy of Pediatrics recommends that children be fully immunized before the age of two years in order for them to be protected during their most vulnerable period. Given according to a specific schedule that is issued every year by the Department of Health, these vaccinations protect against hepatitis B, diphtheria, tetanus, pertussis, measles, mumps, rubella, varicella (chickenpox), polio, and Hemophilus influenza type B (Hi B). This series of vaccinations is recommended by the American Academy of Family Physicians, the American Academy of Pediatrics, and the Centers for Disease Control and Prevention and is required in all states before children can enter school. All states will make exceptions for children who have medical conditions such as cancer that prevent them from having vaccinations, and some states also will make exceptions for children whose parents object for religious or other reasons.

Vaccines are also available for preventing anthrax, cholera, hepatitis A, Japanese encephalitis, meningococcal meningitis, plague, pneumococcal infection, tuberculosis, typhoid fever, and yellow fever.

Some vaccines are combined in one injection, such as the measles-mumps-rubella (MMR) or diphtheria-pertussis-tetanus (DPT) combinations.

Precautions

Vaccines are not always effective, and there is no way to predict whether a vaccine will "take" in any particular person. To be most effective, vaccination programs depend on whole communities participating. The more people who are vaccinated, the lower everyone's risk of being exposed to a disease. Even people who do not develop immunity through vaccination are safer when their friends, neighbors, children, and coworkers are immunized.

Like most medical procedures, vaccination has risks as well as substantial benefits. Anyone who takes a vaccine should make that sure he or she is fully informed about both the benefits and the risks. Any questions or concerns should be discussed with a physician or other health care provider. The Centers for Disease Control and Prevention, located in Atlanta, Georgia, is a good source of information.

Vaccines may cause problems for people with certain allergies. For example, people who are allergic to the antibiotics neomycin or polymyxin B should not take rubella vaccine, measles vaccine, mumps vaccine, or the combined measles-mumps-rubella (MMR) vaccine. Anyone who has had a severe allergic reaction to baker's yeast should not take the hepatitis B vaccine. Patients who are allergic to antibiotics such as gentamicin sulfate, streptomycin sulfate, or other aminoglycosides should check with their physicians before taking influenza vaccine, as some influenza vaccines contain these drugs. Also, some vaccines, including those for influenza, measles, and mumps, are grown in the fluids of chick embryos and should not be taken by people who are allergic to eggs. In general, anyone who has had an unusual reaction to a vaccine in the past should let his or her physician know before taking the same kind of vaccine again. The physician also should be told about any allergies to foods, medicines, preservatives, or other substances.

People with certain other medical conditions should be cautious about taking vaccines. Influenza vaccine, for example, may reactivate Guillain-Barre syndrome in people who have had it before. This vaccine also may worsen illnesses that involve the lungs, such as bronchitis or pneumonia. Vaccines that cause fever as a side-effect may trigger seizures in people who have a history of seizures caused by fever.

Certain vaccines are not recommended for use during pregnancy, but some may be given to women at especially high risk of getting a specific disease such as polio. Vaccines also may be given to pregnant women to prevent medical problems in their babies. For example, vaccinating a pregnant woman with tetanus toxoid can prevent her baby from getting tetanus at birth.

Women should avoid becoming pregnant for three months after taking rubella vaccine, measles vaccine, mumps vaccine, or the combined measles-mumps-rubella (MMR) vaccine as these could cause problems in the unborn baby.

Women who are breastfeeding should check with their physicians before taking any vaccine.