Pneumococcal infections are caused by the Streptococcus pneumoniae bacteria, and range from mild to severe.
There are more than 90 different strains of Streptococcus pneumoniae (S. pneumoniae) bacteria (known as serotypes), some of which cause more serious infection than others.
The symptoms of a pneumococcal infection can vary, depending on the type of infection you have. Common symptoms include:
Pneumococcal infections usually fall into one of two categories:
Non-invasive pneumococcal infections include:
Invasive pneumococcal infections include:
People with a weakened immune system are most at risk of catching a pneumococcal infection. This may be because:
Other at-risk groups include:
Read more about the causes of pneumococcal infections.
Cases of invasive pneumococcal infection usually peak in the winter, during December and January.
Non-invasive pneumococcal infections are usually mild and go away without the need for treatment. Rest, fluids and over-the-counter painkillers such as paracetamol are usually advised.
More invasive types of pneumococcal infections can be treated with antibiotics, either at home or in hospital.
Read more about how pneumococcal infections are treated.
There are two different types of pneumococcal vaccine used. These are:
The PCV protects against 13 types of S. pneumoniae bacteria, and the PPV protects against 23 types. It is thought that the PPV is around 50-70% effective at preventing more serious types of invasive pneumococcal infection.
The outlook for pneumonia in people who are otherwise healthy is good, but the infection can lead to serious complications in people who are very young, very old or have another serious health condition.
However, due to the introduction of the PCV in 2002, the number of people dying from complications that arise from pneumonia has fallen to around 7%.
The outlook for other types of invasive pneumococcal infections such as bacteraemia is generally good, although there is about a 1 in 20 chance that bacteraemia will trigger meningitis as a secondary infection.