Vaccines and immunoglobulins
Vaccines and immunoglobulins are preparations that immunise the body against certain infections diseases.
|Vaccines: BCG, Diphtheria, Haemophilus b, Hepatitis A, Hepatitis B, Influenza, Measles/Mumps/Rubella (MMR), Meningococcus C, Pertussis, Pneumococcus, Polio, Rabies, Tetanus, Typhoid, Yellow fever||Immunoglobulins: Anti-D, Cytomegalovirus, Hepatitis B, Normal immunoglobulin, Rabies, Tetanus, Varicella-zoster|
How do they work?
There are two forms of immunization, which are known as active immunization and passive immunization (see How immunization works). In active immunization, vaccines are given to stimulate the immune system to produce its own antibodies. A different vaccine must be given for each disease because each type of infectious organism triggers the production of a specific type of antibody. Some vaccines contain live organisms that have been altered and made harmless. Others contain killed organisms, part of an organism, or a toxin (poison) made by bacteria. All forms of vaccine have the same effect of priming the body's immune system to produce appropriate antibodies so that the body is ready to fight off particular invading organisms. Passive immunization uses immunoglobulins and works by introducing donated antibodies into the blood. These antibodies destroy infectious organisms that are present or that enter the body shortly afterwards.
Why are they used?Some highly infectious diseases cannot be treated effectively or can be so serious that prevention, in the form of active or passive immunization, is recommended. Active immunization with vaccines is used mainly to prevent diseases from spreading within a community. If most people are vaccinated, some diseases may eventually disappear. In developed countries, children are routinely given active immunization against a range of diseases, including measles, tetanus, and pertussis (whooping cough), from the age of 2 months to 15 years (see Routine immunizations). Other vaccines are used for specific groups of people. For example, immunization against influenza is recommended for people who are at risk of becoming seriously ill if they develop the disease. Those at high risk include elderly people, those who have reduced immunity because of diseases such as diabetes mellitus, and people with long-term heart or lung disease. There are many different types (strains) of influenza, and a specific vaccine is required for each one. New influenza vaccines are usually created each year to match the viral strains predicted to be most widespread. Vaccines are also used for people who are at increased risk from certain infections. For example, people travelling to a developing country are advised to receive immunization against diseases that are common in that region (see Travel immunizations). The main use of passive immunization with immunoglobulins is in cases where rapid protection against disease is necessary, for example after exposure to infection. This process is also used to provide antibodies against particular infections in people whose immune systems are suppressed due to disorders such as HIV infection and AIDS or as a result of certain drug treatments (see Immunosuppressants).
How are they used?
Vaccines are given by injection (although polio vaccine used to be given orally). Many vaccines provide lifelong immunity with one dose or a course of several doses, but some may not give full protection or may be effective for only a few months or years. The degree of protection given depends largely on the strength of the immune reaction a vaccine provokes. Additional doses, known as booster doses, may be needed at regular intervals to reinforce the effect of the original course of a vaccine and to maintain immunity.
Often, vaccines against more than one infection are given in a combined preparation, limiting the number of injections that are needed. For example, vaccines against measles, mumps, and rubella (MMR) are given together.
Immunoglobulins are given by injection into a muscle or intravenously. They are effective for a short period only, and protection diminishes over several weeks, partly depending on the dose. If continued protection is needed, the treatment must be repeated.
What are the side effects?Some vaccines, such as the polio vaccine, cause few side effects. Others, such as the measles, mumps, and rubella (MMR) vaccine, may produce mild forms of the diseases. Many vaccines may cause a red, tender area at the injection site and a mild fever or flu-like illness that lasts a few days. Severe side effects, including the allergic reaction anaphylaxis, are rare. For most people, the risks are far outweighed by the protection given. In some cases, vaccines should not be given. If you or your child has a fever, vaccination should be postponed until the fever has subsided. Vaccines containing live organisms should not be given during pregnancy or to those who have some types of cancer or whose immune systems are suppressed (although HIV-positive people can have MMR unless they are severely immunosuppressed). Side effects of immunoglobulins are uncommon but may include tenderness at the injection site and fever. Repeated immunoglobulin treatment may result in an allergic reaction, such as a rash.
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