Pneumococcal infections are acute infections that are caused by the bacteria known as streptococcus pneumoniae (s. pneumoniae).
There are over 90 different strains of s. pneumoniae, but it is thought that most infections are caused by 10 strains.
Types of pneumococcal infection
Pneumococcal infections are usually one of two types:
- non-invasive pneumococcal infections, which occur outside the major organs or the blood, and tend to be less serious, and
- invasive pneumococcal infections, which occur inside a major organ, or in the blood, and tend to be more serious.
Non-invasive pneumococcal infections
Non-invasive pneumococcal infections include:
- middle ear infection (otitis media),
- infection of the sinuses (sinusitis), and
- infection of the airways (bronchitis).
Invasive pneumococcal infections
Invasive pneumococcal infections include:
- pneumonia (lung infection),
- meningitis (infection of the brain), and
- infection of the blood (sepsis).
How common are pneumococcal infections?
Non-invasive pneumococcal infections are thought to be quite common, although it's hard to estimate the exact number of cases that occur each year in England. This is because infections usually clear up within a few days, so people don't usually have to visit their GP.
Invasive pneumococcal infections are less common than the non-invasive variety, but they can place a considerable strain on health services. For example, in England and Wales it's estimated that 40,000 people require hospital treatment due to pneumonia every year.
Meningitis is a medical emergency that requires immediate treatment in an intensive care unit (ICU). However, it's much rarer than pneumonia, with only one in 100,000 people developing the condition each year.
Cases of invasive pneumococcal infection usually peak in the winter, during December and January.
Vaccinations
There are two vaccinations that are used for the most common strains of pneumococcal infections. They are:
- the pneumococcal conjugate vaccine (PCV), which all children under the age of two should receive as part of their childhood vaccination programme, and
- the pneumococcal polysaccharide vaccine (PPV), which is recommended for all adults over 65 years of age. This is also recommended for those who are over two years of age and in a high risk group for developing a pneumococcal infection, such as people with diabetes or heart disease.
See the causes section for more information about who is recommended to receive a PPV vaccine.
Trends in pneumococcal infections
Since the introduction of the PCV in 2002 and the PPV in 2003, the number of cases of invasive pneumococcal infection has fallen by 50%.
However, there is concern about the number of s. pneumoniae that have developed a resistance to antibiotics. These types of bacteria are known as drug-resistant streptococcus pneumoniae (DRSP).
In England and Wales it is estimated that about 4% of s. pneumoniae are resistant to drugs. Infections that are caused by DRSPs can be much more challenging to treat.
GPs are becoming increasingly reluctant to prescribe antibiotics for cases of mild non-invasive infection because each time an antibiotic is used the chances of the bacteria developing a resistance to it are increased.
