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There are two main types of immunisation, active immunisation and passive immunisation.
Both types of immunisation prepare the body to fight against certain diseases, in case we come into contact with them in the future.
Active immunisation is when a substance, known as a "vaccine", is introduced into the body (usually by injection) to encourage the body's immune system to produce antibodies against a particular disease.
Antibodies are proteins that are produced by the body to neutralise or destroy disease-carrying organisms and toxins. Active vaccines may be made from tiny amounts of the disease organism that have been killed, or weakened. They may also be created artificially from other genetic material (recombinant).
After receiving an active immunisation against a disease, your immune system should have the antibodies that are needed to fight it successfully .
Passive immunisation is when the body is given a vaccine containing ready-made antibodies against a disease. Passive immunisation only provides short-term protection from disease.
Vaccination is the name given to all forms of immunisation. A wide range of vaccines is available to protect against different infectious diseases.
Why it is necessary
Why adult immunisation is necessary
Vaccination is very effective in preventing and reducing the impact of serious illness. Some diseases, such as smallpox, have been completely wiped out, and it is hoped that others, such as polio and measles, will soon be destroyed.
However, if people are not vaccinated, these diseases could return. They could also be brought back into this country from parts of the world where they are still common. This is why it is important to maintain the rates of vaccination.
Vaccination protects the wider community, as it makes it harder for the disease to find an unprotected person to infect, and to spread widely enough to cause an epidemic. For a highly infectious disease, such as measles, about 95% of people need to be vaccinated to give this protective effect, known as herd immunity.
Certain diseases, such as rubella (German measles), are particularly harmful to an unborn baby if caught during pregnancy. Therefore it is important that both girls and boys are vaccinated against these diseases, to prevent them being passed to pregnant women.
How it works
How adult immunisation works
The immune system works to protect the body from potentially harmful organisms, such as bacteria and viruses. We are born with some degree of protection (innate immunity) which is provided by physical barriers to infection, such as the skin.
Antibodies against infection are also passed from mother to baby through the placenta during development in the womb. However, as a baby get older, some of the natural immunity that they are born with, starts to wear off as the immune system develops fully. Also, innate immunity does not protect us against all the organisms that cause disease.
When organisms overcome the defences of the innate immune system, your body responds by fighting each specific type. The body 'memorises' each organism 'fought' so that its response is even more efficient the next time the organism invades your body.
To do this, your body creates antibodies that recognise each specific disease and are ready to fight it. You have then developed 'acquired immunity' to the disease. This usually means a much milder effect on the body, or none at all, should you come into contact with the disease in the future.
However, without vaccination, it can take days, or weeks, to acquire immunity to a particular disease. During this time, you can become seriously ill, and may even die. A vaccination programme introduces enough tiny quantities of the disease to encourage your body to create antibodies quickly.
When it should be done
When adults should be immunised
Most vaccinations are given during childhood.
Tetanus - providing that your childhood vaccinations are up-to-date, a tetanus booster is only required for people who are at risk of contracting tetanus following an injury or animal bite.
- Polio - boosters are advised every 10 years for healthcare workers who may be exposed to the disease.
- Hepatitis B - this vaccination is offered to people who may come into contact with the disease, such as healthcare workers.
Influenza (flu) vaccine
If you are in an at-risk group for developing complications from a flu infection, you should get a yearly vaccination. At-risk groups include:
- people who are 65 years of age, or over,
- people with a serious heart problem, such as heart failure,
- people with serious asthma, or chronic obstructive pulmonary disease (COPD),
- people with a long-term kidney, or liver, disease,
- people with diabetes, and
- people with a weakened immune system as a result of an illness, such as HIV (human immunodeficiency virus) or AIDS, or due to treatment, such as chemotherapy.
Everyone over 65 years of age should get a pneumococcal vaccination, which provides protection against illnesses that are caused by the type of bacteria known as streptococcus pnuemoniae. These bacteria can cause a number of serious illnesses, such as pneumonia, blood poisoning, and meningitis.
Often, the pneumococcal vaccination can be given at the same time as the flu vaccination. However, unlike the flu vaccination, you should only need to have the vaccine once.
The Bacille Calmette Guérin (BCG) immunisation programme, which offers protection against tuberculosis (TB), identifies those who are most at risk of catching TB. In particular, those living in areas that have a high rate of TB, or whose parents or grandparents were born in a country where TB is common, are targeted and vaccinated. BCG is no longer routinely given to children aged between 10-14 years.
Parts of the world where TB is common are listed below.
- Africa - particularly South Africa, Nigeria, Ethiopia, the Democratic Republic of the Congo, Tanzania, Mozambique, Kenya, Uganda, and Zimbabwe.
- Asia - particularly India, Indonesia, Pakistan, China, Thailand and the Philippines,
- Brazil, and
Vaccinations are available to people travelling to areas where they may be exposed to serious diseases, such as cholera, typhoid, or yellow fever. You should visit your GP surgery well in advance of your departure to obtain advice about which vaccines will be required for your trip.
Some vaccinations need to be taken several months before travelling to a country, so you should plan your vaccination schedule well in advance.
Your GP, or practice nurse, may only be able to provide some vaccinations free. These may vary across practices but usually include:
- hepatitis A,
- meningitis C, and
- tetanus, diphtheria and polio (which are combined in one vaccine).
Other vaccinations are not usually free. Your GP may charge for them (including an administration fee) or refer you to a special travel clinic. They include:
- yellow fever,
- meningococcal meningitis,
- Japanese and tick-borne encephalitis,
- hepatitis B, and
There is no vaccination available for malaria but there are anti-malarial medicines that should prevent you catching the condition if you travel to an at-risk country. Anti-malarial medicine is normally taken one week prior to the trip, during the trip, and for up to one month after the trip. However, these times will vary according to the type of medicine you are taking.
How long does a vaccination last?
Depending on the disease being vaccinated against, the protection provided can last from between a few years, to life. The effectiveness of each vaccination varies from near total protection - for example, MMR with pre-school booster - to only partial protection from some diseases, such as typhoid fever.
Side effects of adult immunisation
Side effects will vary depending on the type of vaccination that you have. Also, any side effects that you experience will usually be mild and short-lived. Some possible side effects are listed below.
- Redness, or swelling, at the injection site.
- Fever (a high temperature of 38°C, or 100.4F, or over) - paracetamol or ibuprofen can be used to reduce a temperature. However, if you have asthma, heart failure, or you have, or have had, stomach problems, such as a peptic ulcer, you should not take ibuprofen.
- Mild symptoms of the disease being vaccinated against - for example, mild rubella, a measles-like rash.
In rare cases, some people have a serious reaction to a vaccine. This is known as anaphylactic shock. This is a type of hypersensitive (allergic) reaction triggered by exposure to an antigen (a substance which the body recognises as alien).
This could be due to a tiny amount of antibiotics, which are used during the manufacture of the vaccine, or egg protein that is used during manufacture.
Anaphylaxis caused by vaccination is very rare. However, if you have any concerns, you should speak to your GP, practice nurse, or health visitor . Alternatively, you can call NHS Direct on 0845 4647 before you have the vaccination.
Cautions with adult immunisation
There are very few people who would not benefit from being vaccinated against serious disease. However, you should tell your GP, practice nurse, or health visitor, if you, or the person being vaccinated:
- has a fever (a high temperature of 38°C, or 100.4F, or over)
- has had a severe reaction to previous vaccinations,
- has a blood disorder,
- has recently received treatment for a serious illness, such as cancer, or has had a transplant,
- has an illness which affects your immune system, such as lupus, or
- is taking high-dose steroids, or has a known allergy to the antibiotics neomycin, or kanamycin.
NHS Choices links
- News: flu jabs
- News: malaria vaccine hope
- Live well: student health
- Tool: screening & testing
- Health A-Z: tetanus
- Health A-Z: flu jab
- Health A-Z: pneumococcal jab