Introduction

Pneumococcal infections are caused by the Streptococcus pneumoniaebacteria, and range from mildto severe.

There are more than 90 different strains ofStreptococcus 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:

• a high temperature (fever) of38C (100.4F)
• aches and pains
• headache

Types of pneumococcal infection

Pneumococcal infections usually fall into one of two categories:

• non-invasive pneumococcal infections these occur outside the major organs or the blood and tend to be less serious
• invasive pneumococcal infections these occur inside a major organ or the blood and tend to be more serious

Non-invasive pneumococcal infections

Non-invasive pneumococcal infections include:

• Bronchitis infection of the bronchi (the tubes that run from the windpipe down into the lungs)
• otitis media ear infection
• sinusitis infection of the sinuses

Invasive pneumococcal infections

Invasive pneumococcal infections include:

• bacteraemiaa relatively mildinfection of the blood
• septicaemia ( blood poisoning )amore serious blood infection
• osteomyelitis infection of the bone
• septic arthritis infection of a joint
• pneumonia infection of the lungs
• meningitis infection of the meninges (the protective membranes surrounding the brain and spinal cord)

Who is at risk?

Peoplewith a weakened immune system are most at risk of catching a pneumococcal infection. This may be because:

• they have a serious health condition, such as HIV or diabetes, that weakens their immune system
• they are having treatment or taking medication that weakens their immune system, such as chemotherapy

Other at-risk groups include:

• babies and young childrenunder two years of age
• adults over 65 years of age
• people who smoke or misuse alcohol

Rest, fluids and over-the-counter painkillers such as paracetamol are usually advised.

More invasive types ofpneumococcal infections can be treated with antibiotics ,either at home or in hospital.

These are:

• pneumococcal conjugate vaccine (PCV) which is given to all children as part of the childhood vaccination programme ; it's given in three separate doses at eight and 16 weeks and at one year of age
• pneumococcal polysaccharide vaccine (PPV) which is given to people aged 65 years or over, and others who are at high risk

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.

Read about pneumococcal vaccination and when pneumococcal vaccinationis used .

Outlook

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 a1 in 20 chance that bacteraemia will trigger meningitis as a secondary infection.