What if I forget about or delay immunisations?
If the usual schedule is interrupted or delayed for any reason, it can be resumed at any time. There is no need to start again. However, it is best to have the immunisations at the correct time, as the earlier the child is protected, the better. Some exceptions to this rule are:
- Pertussis (whooping cough) vaccine is not usually given to children over the age of seven years.
- Meningitis C vaccine (MenC). If the child starts immunisation over the age of four months, then only two doses of MenC are needed, four weeks apart. If the child is over one year old and has not had any previous doses of MenC then only one dose is needed.
- Hib vaccine. If the child is over 13 months but under four years, and has not had any previous doses, then only one dose is needed. Hib is not given to children aged over four years, as the risk of infection from this bacterium is much less than in young children and babies.
- Pneumococcal conjugate vaccine (PCV). If a child between the ages of one and two years has not had any previous dose of PCV, or only had one previous dose, then a single dose of PCV should be given. Children aged over two years and who are not in an at-risk group do not need to be immunised.
Who should NOT be immunised?
There are very few reasons why children should not receive their full course of immunisations. Immunisations are generally safe and effective. For some immunisations the two most common reasons why it might not be advisable are:
- If the immune system is not working properly then some vaccines are not given. For example, in children with HIV infection, children undergoing chemotherapy or who are receiving high doses of steroids.
- If a child has previously had a severe reaction to the same vaccine.
See the separate leaflets on the individual immunisations for more detail.
Which diseases are prevented with childhood immunisations?
Diphtheria is caused by the bacterium Corynebacterium diphtheriae. It causes a serious throat and chest infection. Since immunisation was started in the 1950s, diphtheria has now become rare in the UK.
Haemophilus influenzae type b (Hib) is a bacterium which can cause pneumonia and meningitis. Children under the age of four are most at risk. Before the introduction of the vaccine in 1992, 1 in 600 children developed some form of Hib disease before their fifth birthday. It is now rare.
Measles is caused by the measles virus. It causes a miserable feverish illness with a rash. Complications occur in some cases such as pneumonia, convulsions or encephalitis (brain inflammation). Before the introduction of a measles vaccine in 1968, measles was a common childhood illness. It is now rare in the UK, although the incidence of measles is increasing in some areas due to some children not being immunised.
Mumps is caused by the mumps virus. The infection typically causes inflammation and swelling of the salivary glands. Complications occur in some cases, such as pancreatitis, orchitis (inflammation of the testes), meningitis, and encephalitis (inflammation of the brain). Mumps may cause permanent deafness in one ear. Again, mumps is now rare in the UK due to immunisation.
Rubella (German measles) is caused by the rubella virus. It causes a mild illness with a rash. However, if a pregnant women has rubella, the virus is likely to cause serious damage to the unborn child. The child is likely to be born with multiple defects (congenital rubella syndrome). The aim of rubella immunisation is to eliminate the rubella virus from the community as much as possible. Since rubella immunisation was introduced in 1970 there has been a dramatic fall in the number of babies born with the congenital rubella syndrome.
Group C meningococcus is a bacterium (germ) which is one cause of meningitis and septicaemia (severe blood poisoning). There are other types of meningococcus, but cases of meningitis and septicaemia caused by group C have fallen since immunisation was introduced.
Pertussis (whooping cough) is caused by a bacterium called Bordetella pertussis. This causes a prolonged and distressing cough. Some infected children develop complications such as pneumonia or brain damage. There used to be regular epidemics of whooping cough in the UK before immunisation became available. It is now uncommon in the UK.
Pneumococcus is a bacterium which can cause pneumonia, meningitis and some other infections. Pneumococcal infection can affect anybody. However, young children, people aged 65 and over, and some other groups of people are at increased risk of pneumococcal infection.
Poliomyelitis (polio) is an illness caused by the polio virus. The virus first infects the gut, but then travels to the nervous system and can cause a meningitis-like illness. This may damage some nerves. This may lead to wasting of muscles and sometimes paralysis of one or more of the limbs. The illness can seriously affect breathing in some people and may even lead to death.
Tetanus is an infection caused by a bacterium called Clostridium tetani which is found in the soil. It causes severe and agonising muscle contractions and is often fatal. Due to immunisation, it is very uncommon in the UK.
Human papillomavirus (HPV) is a virus that can affect the skin and mucosa (the moist membranes lining different parts of the body, including the mouth, throat and genital area). There are over one hundred different types of HPV and about 40 of these can affect the genital area. Two types, HPV 16 and 18, are involved in the development of most of the cases of cancer of the cervix. The HPV vaccine is very effective at stopping cancer of the cervix from developing.
How does immunisation work?
The body is given a vaccine which is a small dose of an inactive form of a bacterium or virus (germ) or a toxin (poison) made by the germ. As it is inactive it does not cause infection. However, the body makes antibodies and/or immune cells (white blood cells) against the germ or toxin. Antibodies are proteins in the bloodstream that attack infecting germs. Once we are immunised, the antibodies and/or immune cells are ready to attack the germ if it begins to invade our body. More antibody can quickly be made from cells which have previously made the particular antibody.
For some bacteria and viruses it has been difficult to produce a vaccine; however, technology is advancing and new vaccines will be available in the future.
A newborn baby has passive immunity to several diseases, such as measles, mumps and rubella, from antibodies passed from its mother via the placenta. This passive immunity of babies usually only lasts for a few weeks or months but, for measles, mumps and rubella, it lasts up to one year. Immunisation with vaccines is called active immunity and provides long-term immunity.