Vostrosky, C. ‘‘A Study of Imaginary Play Companions.’’ Education
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Rebecca B. McCathren
M. Gutierrez
G. Holliday
IMMUNIZATION
Immunization is recognized as one of the greatest
public health achievements of the twentieth century.
The widespread use of immunization is responsible
for dramatic reductions in, and in some cases the
elimination of, specific infectious diseases.
Goals of Immunization
Immunizations can partially or completely pre-
vent illness by a specific microorganism. By prevent-
ing illness, immunizations avert the acute effects of
disease, complications of disease, and long-term dis-
ability related to disease. When immunizations are
widely used, the spread of disease within the popula-
tion can also be prevented. By preventing outbreaks
of disease, immunizations reduce health-care expen-
ditures, including the costs of: (1) prescription and
over-the-counter medications, (2) health-care provid-
er visits (including office and emergency room visits),
(3) hospitalization, and (4) long-term disability or
long-term care. Immunizations also save money by
reducing the number of days of work loss by employ-
ees because of personal illness or illness in a depen-
dent family member.
Immunizations can provide active or passive pro-
tection against an infectious disease. In active immu-
nization, entire organisms (e.g., inactivated bacteria;
live, weakened virus) or their parts (e.g., bacterial tox-
oid; inactivated, viral antigen) are administered. The
immune system responds to the vaccine by producing
a long-lasting, protective immune response in the re-
cipient. Examples of active immunization include all
of the vaccines used in the standard childhood immu-
nization schedule (see Table 1). In passive immuniza-
tion, preformed antibodies against specific
microorganisms are administered. Protection lasts
only months because of the relatively short half-life of
the antibodies. Passive immunization is used before
or immediately after an exposure to an infectious
agent to prevent infection. Passive immunization is
used for a number of infectious agents, including
hepatitis B, rabies, respiratory syncitial virus, tetanus,
and varicella-zoster. The remainder of this discussion
will be directed toward active immunizations used
during childhood.
Immunizations can be recommended on either a
universal or a selective basis. Universal immuniza-
tions are directed at all members of a population. The
eventual goal of immunizing all susceptible individu-
als is the complete eradication of a disease, as in the
case of smallpox. Selective immunizations are direct-
ed at individuals who are considered at high risk of
a disease, or at high risk of complications of a disease.In the United States, the choice and timing of im-
munizations are made jointly by three national orga-
nizations—the Advisory Committee on Immunization
Practices branch of the federal government’s Centers
for Disease Control and Prevention, the Committee
on Infectious Diseases of the American Academy of
Pediatrics, and the American Academy of Family Phy-
sicians. The complete schedule for universal immuni-
zations is updated and published annually (see Table
1). Alterations to the schedule (e.g., addition of newly
approved vaccines and changes in the timing of vac-
cines) can nevertheless be made throughout the year.Immunization Success
Immunization against smallpox is an example of
the success possible through universal vaccination
programs. Accounts of immunization against small-
pox were reported as long ago as the 1600s. At that
time, uninfected individuals were exposed to material
(e.g., pus) from patients suffering from mild disease
in the hopes of preventing more serious or fatal dis-
ease. In the late 1700s, Edward Jenner, a physician in
England, promoted the widespread use of the cowpox
virus to prevent smallpox. Two centuries later, on Oc-
tober 26, 1979, the World Health Organization de-
clared that smallpox had been eradicated from the
entire world.The success of other immunization campaigns in
the United States is shown in Table 2. The incidence
of vaccine-preventable disease has been reduced be-
tween 97.6 and 100 percent through the use of uni-
versal immunization.This success could not have been achieved with-
out the combined efforts of researchers, health-care
providers, and families. Researchers are responsible
for the development of a wide variety of safe, effective
vaccines against common childhood diseases. Health-
care providers are responsible for ensuring that chil-
dren receive the appropriate and required immuniza-
tions. And families are responsible for bringing their
children in for routine child-health supervision visits.
At the beginning of the twenty-first century in the
United States, record numbers of children were being
immunized. This is an essential part of the success of
immunizations in this country.IMMUNIZATION 201