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:
- a high temperature (fever) of 38C (100.4F)
- aches and pains
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:
- bacteraemia – a relatively mild infection of the blood
- septicaemia (blood poisoning) – a more 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?
People with 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 children under two years of age
- adults over 65 years of age
- people who smoke or misuse alcohol
Read more about the causes of pneumococcal infections.
Cases of invasive pneumococcal infection usually peak in the winter, during December and January.
Treating pneumococcal infections
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:
- 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.
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.
Multidrug-resistant Streptococcus pneumoniae (MDRSP)
During the 1990s, the increasing levels of S. pneumoniae that had developed a resistance to three or more types of antibiotics was a major concern. These types of bacteria are known as multidrug-resistant Streptococcus pneumoniae (MDRSP).
MDRSP is a real concern because it is challenging to treat and carries a higher risk of causing complications.
Since the introduction of pneumococcal vaccines, fewer cases of infection have led to antibiotics being used less and the chance of bacteria developing resistance to antibiotics becoming smaller.
The ability for bacteria to become resistant to antibiotics is the reason why GPs are becoming increasingly reluctant to prescribe antibiotics for mild infections.