Diphtheria is a serious infection that initially affects the throat. It can progress to damage nerves and heart muscle, and can kill.

It is very rare in this country, but there was an epidemic in Russia in the early 1990's following the collapse of their immunisation programme.

Hib is short for haemophilus influenzae type B,( it shouldn't be confused with the germ that causes flu). Hib can cause pneumonia, blood poisoning and one type of meningitis. It can also cause a dangerous form of croup.

Measles is another virus infection . It causes a high fever and a rash. Complications include chest and ear infections, fits and occasionally brain damage.

About one out of every 1000 to 2000 children with measles get a serious brain infection called encephalitis which causes a high fever, fits and coma.

Rarely, in around 10 in a million children with measles, a chronic brain disease called SSPE develops. This condition can start many years after the child has had measles and is almost always fatal.

Meningitis C is one kind of meningitis.  There are several other types of meningitis. It is a dangerous infection that affects the covering of the brain. It can also cause septicaemia (blood poisoning). If it is not treated rapidly it can be fatal.

Look for the following symptoms in babies

• The baby may be difficult to wake, or look very sleepy, or have a staring expression
• A high temperature
• Irritability when picked up, with a high pitched moaning cry
• Refusing to feed, or vomiting
• Sometimes diarrhoea
• Pale or blotchy skin
• Red or purple spots that don't fade when a glass is pressed on them
• A stiff body with jerky movements or else floppy and lifeless
• The soft spot may be tense or bulging

Look for the following signs in older children

• Stiffness of the neck, the child may not be able to kiss his or her knee, or put his or her forehead on the knee.
• Red or purple spots that don't fade when a glass is pressed on them.
• A severe headache
• Confusion or drowsiness
• A dislike of bright light

Not all babies or children get all these symptoms, so trust your instinct and if you think you child is very ill get help immediately. Visit the Meningitis Research Foundation website for more information about meningitis and how to diagnose it.

If you think your child may have meningitis, get urgent medical help.
See "how to get help in an emergency".

The mumps virus causes swollen glands on the sides of the neck. Rarely it causes infertility by affecting the testicles. before the vaccine was introduced, it was the commonest cause of viral meningitis in children under 15. 

Pneumococcal infection

This infection causes pneumonia, septicaemia, bronchitis and a type of meningitis. 

The vaccine is part of the childhood immunisation programme and is recommended for the over 65's and anybody who would normally be eligible for a flu vaccination.

Polio is a virus that attacks the nervous system. It can cause permanent muscle paralysis and if it affects the chest muscles it can be fatal. 

The old vaccine, given by mouth, contained live viruses, and very occasionally caused infection in contacts of the person immunised. 

The new injectable vaccine is inactivated, that is to say, there are no live viruses in it. It doesn't cause infections in other people.

The main danger from rubella is to the unborn child. If a woman catches rubella in early pregnancy the baby can develop brain damage and deafness.

Some children develop a  rash like measles about 7-10 days after the vaccination, together with a fever and loss of appetite. They can also get symptoms of rubella and mumps which are milder than the real diseases. This is part of the body's process of developing immunity to these diseases.

Rarely children may have a bad reaction to the MMR vaccine. About one in a 1000 children has a febrile fit. However a child who catches measles is 10 times more likely to have a fit.

Tetanus is caused by a germ in the soil. It can be caught by a wound that is contaminated with soil. Penetrating wounds are particularly dangerous as the germ multiplies best away from the air. The wound does not have to be serious to get tetanus, a prick from a thorn may be enough. Also, it doesn't matter how many times someone is exposed to the germ, they will never develop immunity naturally.

Tetanus is very dangerous, causing muscle spasms and breathing problems and up to half those affected may die. 

Everyone, children and adults, should make sure that they have a full course of tetanus vaccine. A full course is three injections a month apart. A booster is needed after 5 years then again a further 10 years later. Boosters may also be needed after some wounds, check with the practice nurse.

TB is a serious infection that attacks the lungs. It was often fatal before the invention of anti-TB drugs. It can also affect the bones and brain. There are still around 5,000 cases a year in this country. There is an increasing problem with resistance to anti-TB drugs.

The vaccination is called BCG. Before giving this a skin test is performed to check if the child is already immune. 

The Chinese word for whooping cough is "100 day cough". This disease is at the least very unpleasant as it causes severe prolonged spasms of coughing. It is called whooping cough because at the end of the coughing fit the child takes a deep breath that sounds like a "whoop". The prolonged coughing fit often causes vomiting.  At worst the illness can be fatal, or can cause lung damage that affects the child in later life.