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Immunization and Children's Physical Health

Childhood Immunizations, Vaccine-Preventable Diseases, Immunization Safety

With the exception of safe water, no other public health intervention has had a greater impact in reducing deaths related to infectious disease than vaccinations. Smallpox was eradicated in 1977; wild-type poliomyelitis was eliminated from the Western hemisphere in 1991. Among children under five, measles and invasive Haemophilus influenzae type b (Hib) have both been reduced to record low numbers. Deaths associated with smallpox, diphtheria, pertussis, tetanus, paralytic poliomyelitis, measles, mumps, rubella, congenital rubella syndrome, and Hib decreased an average of nearly 100 percent during the twentieth century.

Though the United States is reaching record low levels of vaccine-preventable disease, continued immunization is important. Pathogenic viruses and bacteria still circulate in the United States, and with continuing globalization, the threat of disease spread increases. Immunization protects the general population from disease; individuals who are immunized have inherent protection from disease while those who are not immunized are protected by the limited likelihood that they will be exposed to another unimmunized and infected individual. Furthermore, immunization protects a population from disease; vaccinated individuals acquire immunologic protection from pathogens for themselves. As a consequence, immunized individuals are protected secondary to a decreased incidence of disease. This phenomenon of herd immunity, however, will not be achieved unless 80 percent to 95 percent of the population is immunized.

Childhood Immunizations

A detailed childhood immunization schedule is released yearly by the National Immunization Program (NIP), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP). This schedule informs parents and health care providers which vaccines children need to receive and when they should receive them. An updated schedule can be found at the website of the Centers for Disease Control and Prevention.

State governments are responsible for passing and enforcing school immunization laws. Currently all fifty states have immunization requirements for children entering school. The vaccinations required may be different for different states. Additionally, states may also differ in the number and types of philosophical or religious exemptions they allow for children entering school. Vaccination decreases the risk of infection and outbreaks in schools by reducing the number of unprotected people who may be infected that are capable of transmitting the disease within their schools and communities.

Immunizations are available either free of charge or for a reduced cost at local health departments for children whose parents cannot afford to take their children to private physicians for immunization. Furthermore, on August 10, 1993, the Omnibus Budget Reconciliation Act (OBRA) created the Vaccines for Children Program (VFC) program as Section 1928 of the Social Security Act in order to increase access to immunizations. The program began on October 1, 1994; it provides vaccinations at no cost to VFC-eligible children seeing either public or private providers.

Vaccine-Preventable Diseases

The following eleven vaccine-preventable diseases are addressed through standard vaccination programs. A number of these diseases are covered by mandatory school immunization laws.

Diphtheria is a respiratory disease caused by a virus that is spread by coughing and sneezing. Symptoms include sore throat and low-grade fever. Left untreated, diptheria can lead to airway obstruction, coma, and death. Vaccines that contain the diptheria toxoid include the DTP, DtaP, DT, and Td vaccines.

Tetanus (lockjaw) is a disease of the nervous system that is caused by bacteria that enters the body through a break in the skin. Early symptoms include lockjaw, stiffness in the neck and abdomen, and difficulty in swallowing. Later onset symptoms include fever, elevated blood pressure, and severe muscle spasms. Death occurs in one third of all cases, especially among the elderly. Tetanus toxoid is also contained in the DTP, DT, DtaP, and Td vaccines.

Pertussis (whooping cough) is a highly contagious bacterial respiratory disease spread through coughing and sneezing. Symptoms include severe fits of coughing that may interfere with eating, drinking, and breathing. Pertussis may cause pneumonia, encephalitis, and infant death. The pertussis vaccine is contained within the DTP and DtaP vaccines.

Haemophilus influenzae type b is a bacterial infection that predominantly affects infants. It is spread by coughing and sneezing. Symptoms include skin and throat infections, meningitis, pneumonia, sepsis, and arthritis and may be severe for children under the age of one. Risk of disease is reduced after the age of five. A Hib vaccine can prevent the disease.

Hepatitis A is caused by the Hepatitis A virus and is spread most commonly through the fecaloral route when the stool of an infected person is put into another person's mouth. It can also be transmitted by ingesting food or water that contain the virus. The disease affects the liver. Symptoms are unlikely, but if present they may include yellow skin or eyes, fatigue, stomach ache, loss of appetite, and nausea. This disease is prevented using the Hepatitis A vaccine.

Hepatitis B is caused by the Hepatitis B virus and is spread through sexual contact or through contact with the blood of an infected person. As with the initial clinical presentation of Hepatitis A, infection with Hepatitis B may follow an indolent course and manifest no symptoms. The likelihood of developing Hepatitis B increases with age. If present, symptoms are similar to Hepatitis A. The Hepatitis B vaccine prevents the disease.

Mumps is caused by a virus and is spread through coughing and sneezing. It is a disease that affects the lymph nodes. Symptoms include fever, headache, muscle ache and swelling of the lymph nodes close to the jaw. Infection with the mumps virus may also lead to meningitis, inflammation of the testicles or ovaries, inflammation of the pancreas and permanent deafness.

Measles is a highly contagious respiratory disease caused by a virus that is transmitted through coughing or sneezing. Symptoms include rash; high fever; cough; runny nose; and red, watery eyes lasting about a week. The measles may cause diarrhea, ear infections, pneumonia, encephalitis, seizures, and death. The measles vaccine is contained within the MMR, MR and measles vaccines.

Rubella (German measles) is a viral respiratory disease spread through coughing and sneezing. Symptoms may include a mild rash and fever for two to three days in children and young adults. Complications are severe for pregnant women, whose children frequently have congenital birth defects. The rubella vaccine is contained within the MMR, MR, and rubella vaccines.

Polio is a viral disease of the lymphatic and nervous systems. Transmission occurs through contact with an infected person. Symptoms include fever, sore throat, nausea, headaches, stomach aches, and stiffness in the neck, back and legs. OPV and IPV are the vaccines in current use.

Varicella (chickenpox) is a highly contagious disease caused by bacteria and is spread by coughing or sneezing. Symptoms are a skin rash of blister-like lesions on the face, scalp, or trunk. The varicella vaccine prevents this disease.

Immunization Safety

Before vaccines are approved by the Food and Drug Administration, they undergo rigorous scientific testing to ensure that they are safe and effective. However, differences in each individual's response to an antigenic vaccine challenge account for the rare occurrences ranging from vaccine failure to anaphylaxis. The National Childhood Vaccine Injury Act (NCVIA) of 1986 created the National Vaccine Program Office within the Department of Health and Human Services. It requires that all providers who administer vaccines provide a Vaccine Information Statement that explains the disease and the risks and benefits of vaccination to the vaccine recipient, parent, or legal guardian. The NCVIA also created the Vaccine Adverse Event Reporting System, a mandatory reporting system for health care providers. The National Vaccine Injury Compensation Program was also created under the NCVIA as a no-fault system for compensating people injured by vaccination.


PLOTKIN, STANLEY A., and ORENSTEIN, WALTER A. 1999. Vaccines, 3rd edition. Philadelphia: W. B. Saunders Co.


CENTERS FOR DISEASE CONTROL AND PREVENTION. 2002. "Immunization Laws." <www.cdc.gov/od/nvpo/law.htm>.

CENTERS FOR DISEASE CONTROL AND PREVENTION. 2002. "Parent's Guide to Childhood Immunizations." <www.cdc.gov/nip/publications/Parents-Guide>.

CENTERS FOR DISEASE CONTROL AND PREVENTION. 2002. "Recommended Childhood Immunization Schedule." <www.cdc.gov/nip/recs/childschedule.htm>.


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