Vaccines and Immunoglobulins

Preparations that immunize the body against certain infectious diseases

Common preparations

    Vaccines

  • BCG (tuberculosis)

  • Cholera

  • Diphtheria

  • Hepatitis A

  • Hepatitis B

  • Hib (Haemophilus influenzae type b)

  • HPV (human papilloma virus)

  • Influenza

  • Meningitis A, C, W135, Y

  • Meningococcus C

  • MMR (measles/mumps/rubella

  • Pertussis

  • Pneumococcus

  • Polio

  • Rabies

  • Tetanus

  • Typhoid

  • Varicella zoster

  • Yellow fever

    Immunoglobulins

  • Anti-D

  • Hepatitis B

  • Normal immunoglobulin

  • Rabies

  • Tetanus

A variety of vaccines and immunoglobulins is available to provide protection against particular infectious diseases. The use of these preparations is known as immunization. Vaccines contain infectious organisms that have been modified or killed. Immunoglobulins contain antibodies (proteins made by white blood cells that neutralize or destroy infectious organisms) extracted from the blood of a person who has already had a specific disease. The body’s own defence mechanism, the immune system, is able to combat many infections, but it cannot protect people against all infectious diseases. Immunization with vaccines or immunoglobulins is therefore used to give added protection. The incidence of a number of highly infectious diseases has declined dramatically worldwide since the introduction of immunization programmes. One disease, smallpox, has been eradicated worldwide.

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 seasonal influenza is recommended for people who are at high 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 of seasonal influenza predicted to be most widespread. Specific vaccines may also be created for unexpected outbreaks of new strains of nonseasonal influenza, such as H1N1 influenza (swine flu).

Vaccines are also used for people at increased risk of catching certain infections. For example, travellers to a developing country are advised to receive immunization against diseases 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?

Most vaccines are given by injection (although cholera vaccine is given orally and typhoid may be given orally or by injection). 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 depends largely on the strength of the immune reaction a vaccine provokes. Additional doses (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.

Drug Action: How Immunization Works

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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