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P A R T 3
Drugs acting on the immune system
or less toxic proteins associated with specific disease-
causing organisms. The proteins could be a weakened
bacterial cell membrane, the protein coat of a virus or a
virus (protein coat with the genetic fragment that makes
up the virus) that has been chemically weakened so that
it cannot cause disease. The goal is to cause an immune
response without having the individual suffer the full
course of a disease. Adults may require immunisations
in certain situations: exposure, travel to an area endemic
for a disease they have not had and have not been immu-
nised against, and occupations that are considered
high risk. Children are routinely immunised against
many infections that were once quite devastating. For
example, smallpox was one of the first diseases against
which children were immunised. Today, smallpox is
considered to be eradicated worldwide. Concerns over
biological terrorism have renewed interest in this disease,
and smallpox vaccine is now available for people who
might be at high risk for exposure to a potential attack
by terrorists.
Diphtheria, pertussis, tetanus,
Haemophilus influ-
enzae
B, hepatitis B, hepatitis A, chickenpox, poliovirus,
meningitis, measles, mumps and rubella are all standard
childhood immunisations today (see Figures 18.1 and
18.2). The bacille Calmette-Guérin (BCG) vaccine for
tuberculosis is widely used throughout the world in
countries with a high incidence of tuberculosis to limit
the spread of the disease. However, it is not routinely
used in Australia because the incidence of tuberculosis is
relatively low and it can induce false-positive tuberculin
skin test results. The human papillomavirus (HPV)
vaccine is now recommended for girls to protect against
several of the viruses that cause many cervical cancers.
The use of vaccines is not without controversy. Severe
reactions, although rare, have occurred, resulting in
concerns about the safety of vaccines and their adminis-
tration, especially in children (Boxes 18.2 and 18.3). The
BOX 18.1
Drug therapy across the lifespan
Biologicals
CHILDREN
Routine immunisation for children has become a standard
of care in Australia and New Zealand. Parents should
receive written records of immunisations given to their
children to assure continuity of care.The parent should be
asked to report adverse reactions to any immunisation.
Sensitive children may receive divided doses of their
immunisations to help prevent adverse reactions.
Simple comfort measures—warm soaks at the injection
site, paracetamol to reduce fever or aches and pains,
comfort from parents or caregivers—will help the child to
deal with the immunisation experience.
Parent education is a very important aspect of the
immunisation procedure. Parents may need reassurance
and educational materials when concerns about the safety
of immunisations arise.
Immune sera are used for specific exposures.
ADULTS
There are a number of reasons why adults should receive
certain immunisations. For example, adults who are
travelling to areas with high risk for particular diseases—
and who may not have previously been exposed to those
diseases—are advised to be immunised.
In addition, adults with chronic diseases are advised to
be immunised yearly with an influenza vaccine and once
with a pneumococcal pneumonia vaccine.These vaccines
provide some protection against diseases that can prove
dangerous for people with chronic lung, cardiovascular
or endocrine disorders.The influenza vaccine changes
yearly, depending on predictions of which flu strain might
be emergent in that year.The pneumonia vaccine contains
23 strains and is believed to offer lifetime protection.
Tetanus shots also are recommended for adults
every 10 years or with any injury that potentially could
precipitate a tetanus infection.
Immune sera are used for specific exposures.
OLDER ADULTS
Older people are at greater risk for severe illness from
influenza and pneumococcal infections.The yearly flu
injection and the pneumococcal vaccine should be
stressed for this group.
A tetanus booster every 10 years will also help to protect
older adults from exposure to that illness. Ask the person
about any adverse reaction to previous tetanus boosters
and weigh the risk against the possible exposure to tetanus.
Immune sera are used for specific exposures. Older
adults are at increased risk for severe reactions and should
be monitored closely.
Safe medication administration
Use of allergenic extracts
Many people receive “allergy shots” or injections of
allergenic extracts. These extracts contain various antigens
based on specific standardisations. The exact action of
these extracts is not completely understood, but it has been
shown that, after injection, specific immunoglobulin G (IgG)
antibodies appear in the serum. These antibodies compete
with IgE for the receptor site on a specific antigen that is
the cause of the allergy (IgE is the immune globulin that is
associated with allergic reactions; these antibodies react
with mast cells, causing the release of histamine and other
inflammatory chemicals when they have combined with
the antigen). After repeated exposure to the antigens, the
levels of IgG antibodies increase and the circulating levels
of IgE seem to decrease, leading to less allergic response.
It may take 4 to 6 months of subcutaneous injections of the
allergenic extract every 3 to 14 days to achieve relief from the
symptoms of the allergic reaction. The IgG levels remain high
for weeks or sometimes months, but the individual response
varies widely. Many people are maintained with a weekly
injection once the desired response has been achieved.
