Pneumococcal disease: what you need to know
What is pneumococcal disease?
Pneumococcal disease refers to illness caused by infection with the bacterium Streptococcus pneumoniae (sometimes shortened to Strep. pneumoniae). These bacteria are also known as pneumococci.
Infection with the pneumococcus bacterium can cause:
- otitis media (inflammation of the middle ear and ear drum);
- sinusitis (inflammation of one or more sinuses);
- pneumonia (inflammation of the lungs);
- bacteraemia (presence of bacteria in the bloodstream); and/or
- meningitis (inflammation of the membranes that surround the brain and spinal cord (the ‘meninges’)).
Less commonly, this bacterium can infect other areas of the body, for example, resulting in septic arthritis (infection of a joint) and osteomyelitis (infection of bone, particularly affecting the long bones in children).
(Pneumococcal disease is not to be confused with meningococcal disease, which is caused by a different bacterium and results in meningitis outbreaks and septicaemia, most commonly in children and young adults during winter and early spring.)
Who gets pneumococcal disease?
Pneumococcal disease most commonly affects:
- older adults, over 65 years of age;
- indigenous Australians aged over 50 years;
- young children under 2 years of age;
- people whose immune system is not working properly, including those who have had their spleen removed; and
- people who have an underlying medical condition such as cancer, diabetes or kidney disease.
Worldwide, pneumococcal disease is estimated to cause one million deaths each year, with most of these deaths occurring in children and babies. Among adults, pneumococcal disease most commonly causes pneumonia, while in children, bacteraemia accounts for more than two-thirds of cases.
In indigenous Australians, the overall rate of invasive pneumococcal disease is 3.2 times that among non-indigenous Australians.
How does Streptococcus pneumoniae cause pneumococcal disease?
The bacterium that causes pneumococcal disease — Streptococcus pneumoniae — can be found relatively commonly in the upper respiratory tract (e.g. the nose and throat) of healthy people, particularly young children, without causing any adverse effects.
S. pneumoniae can spread among people when they are in close contact. Tiny droplets of fluid from the nose or mouth of someone carrying the infection are transferred to another person, for example, when coughing, sneezing or kissing, or by babies sharing toys.
The bacterium will not cause ‘pneumococcal disease’ in every person who is exposed to it; in fact this outcome is uncommon among generally healthy people. However, illness is more likely to occur in the very young, the old and the unwell. In these people, the body's defence mechanism — the immune system — may not be able to keep the bacteria at bay. If this occurs, the bacteria can then invade the tissues locally and cause illnesses such as otitis media and sinusitis, or spread down the respiratory tract to cause pneumonia, or they can spread beyond the respiratory tract and cause invasive pneumococcal disease such as meningitis or bacteraemia.
What are the symptoms of pneumococcal disease?
The symptoms depend on which area of your body is affected, and can include the following.
- Otitis media: ear pain; reduced hearing; fever; and irritability.
- Pneumonia: breathing difficulties (more rapid breathing, shortness of breath); cough; chest pain; low energy; lack of appetite; and headache.
- Meningitis: neck stiffness; fever; headache; nausea; and vomiting.
How is it diagnosed?
Your doctor will not be able to diagnose pneumococcal disease based on a physical examination alone. Your signs and symptoms may point to a diagnosis of meningitis or pneumonia, but various different bacteria and viruses can cause these conditions. If you have pneumonia, a chest X-ray cannot identify the organism causing your infection, but it will give an indication of inflammation and infection in your lungs by showing an accumulation of fluid or debris in the air spaces.
A definitive diagnosis of pneumococcal disease can only be made by identifying S. pneumoniae in a blood sample or a sample of cerebrospinal fluid (CSF), or by doing special tests on a sputum (phlegm), urine or CSF sample.
All of these samples are tested in a pathology laboratory. However, because invasive pneumococcal disease is serious, doctors may send the person straight to hospital and the tests may be done there.
In a person who has acute sinusitis or otitis media that may be caused by pneumococcus, the doctor will usually start treatment that covers the possibility of pneumococcal disease, because samples to identify the cause are not easily obtained.
How is it treated?
Pneumococcal disease requires treatment with antibiotics. However, of concern is the increase in resistance to antibiotic treatment displayed by some S. pneumoniae bacteria. Therefore, in a person who is showing symptoms of pneumococcal disease, doctors will often test the bacteria that is present in the person's blood, CSF or sputum sample against various antibiotics in the laboratory. The antibiotic that is most effective at killing the bacteria in these tests — and that is suitable for the patient and the site of infection — will then be prescribed.
However, if a patient has severe pneumonia, for example, doctors will not wait for test results but will start treatment with a broad spectrum antibiotic immediately. A broad spectrum antibiotic is one that is effective against a wide variety of bacteria.
In mild or uncomplicated infections, such as sinusitis or otitis media due to S. pneumoniae, the person may be prescribed antibiotics. However, research has shown that some mild infections clear up spontaneously; your doctor will advise you whether antibiotics are necessary.
Treatment of pneumococcal disease can also include medications to relieve pain, fluids to manage dehydration, and rest.
Can pneumococcal disease be prevented?
Vaccines are available to help prevent pneumococcal disease. Approximately 90 different strains (‘serotypes’) of S. pneumoniae have been found so far, but current vaccines don't offer protection against all of them, however, they do protect against the most commonly encountered serotypes.
A 23-valent vaccine (Pneumovax) helps protect against 23 serotypes of the bacterium and is recommended in the Australian Standard Vaccination Schedule to be given to all adults over 65 and Aboriginal and Torres Strait Islander people over 50 years. It is also recommended as a booster at 18 to 24 months of age for Aboriginal and Torres Strait Islander children in high risk areas, and at 4 to 5 years for children considered to be at increased risk of pneumococcal disease.
A 7-valent vaccine (Prevenar) helps protect against 7 serotypes of the bacterium, in particular, the serotypes that cause the majority of invasive pneumococcal disease in young children. This vaccine is recommended for all Australian children as a 3-dose series at 2, 4 and 6 months of age. Medically at-risk children require a fourth dose at 12 months of age.
Your doctor can talk to you about your risk or your child's risk of pneumococcal disease, and discuss the vaccination schedule that you or your child may require.
Last Reviewed: 10 October 2008
