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P A R T 3  Drugs acting on the immune system

Drug therapy across the lifespan

BOX 18.1

Biologicals CHILDREN

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 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. 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.

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 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. 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. Safe medication administration Use of allergenic extracts Many people receive “allergy shots” or injections of