An individual's resistance to a specific disease or infection depends upon the
presence in the body of protective chemical substances called antibodies. When the
body produces its own antibodies, it is termed active immunity. Active immunity results
from having an infectious disease or from receiving an injection or inoculation of
in days or weeks, but the protection received will last for relatively long periods.
Another type of immunity, described as passive, is acquired. This immunity results from
the body receiving serum that contains antibodies that have been preformed in humans
or animals. Although this serum confers immediate protection, the immunity does not
last as long. Passive immunity does not stimulate antibody formation.
Preparations administered to produce immunity are called immunizing agents.
They are known as vaccines, toxoids, and antiserums. Both vaccines and toxoids
cause the body to produce their own antibodies (bringing about active immunity), while
antiserums produce passive immunity.
a. Vaccines. Vaccines contain either weakened or killed microorganisms (such
as viruses, bacteria, or rickettsia) that are administered for the prevention, improvement,
or treatment of infectious diseases. Examples are typhoid, measles, poliomyelitis, and
b. Toxoids. Toxoids contain suspensions of modified toxins that have lost their
toxicity but which have maintained the properties of combining with antitoxins, or
stimulating the formation of antitoxins. Examples are diphtheria and tetanus toxoids.
c. Antiserums. Antiserums are preparations of blood serum that already
contain an antibody or antibodies. They are used when there is not time to wait for the
body of the exposed or infected person to produce its own antibodies. Examples are
tetanus, immune globulin, and rabies.
THE ARMY IMMUNIZATION PROGRAM
a. Immunizations. The Army requires all its healthy military personnel to be
actively immunized against diseases such as typhoid, tetanus, diphtheria, poliomyelitis,
and influenza. Individuals traveling or assigned to certain areas may be required to be
immunized against yellow fever, cholera, plague, or other diseases. Upon initial
induction, recruits are also given the following vaccines--adenovirus (types 4 and 7),