A chest infection is a bacterial or viral infection of the airways leading down into the lungs, or of the lungs themselves.
The main symptoms of a chest infection include:
- a chesty cough that can often bring up phlegm (thick mucus)
- breathing difficulties
- chest pain
Chest infections can range from being mild to life threatening.
Types of chest infection
There are two main types of chest infection:
- acute bronchitis, which is the more common and less serious type of infection
- pneumonia, which is less common than acute bronchitis but more serious
Acute bronchitis is a short-term infection of the lining of the air tubes of the lungs, which are known as the bronchi.
The infection is usually caused by a virus, and often follows a cold or influenza (flu). Smoking increases your chances of developing the infection. Most people do not require medical treatment because the infection usually passes within seven to ten days.
See the Health A-Z topic about Acute bronchitis for more information about this condition.
Pneumonia is an infection that causes the tiny air sacs in your lungs, known as alveoli, to become inflamed and filled with fluid. Pneumonia is usually caused by bacteria, although some cases can be caused by viruses.
People with mild pneumonia can usually be treated at home. However, if you have severe pneumonia, you may need to receive treatment in hospital. People who are very young or very old, and those with another serious health condition, are more likely to require hospital treatment if they develop pneumonia.
See the Health A-Z topic about Pneumonia for more information about this condition.
How common are chest infections?
Chest infections are very common and account for around one in five GP visits.
Acute bronchitis is the most common type of chest infection, affecting about 4.5% of the UK population each year. The condition is most common during autumn and winter.
Pneumonia is less common, affecting just over 1% of people each year in the UK.
People who are over 65 years of age are most at risk of developing pneumonia, and the rates of pneumonia are four times higher in this age group compared with other age groups. As with acute bronchitis, pneumonia is most common during the autumn and winter months.
Chest infections are contagious
Although acute bronchitis and pneumonia are not as contagious as conditions such as flu, they can be passed on to others through coughing and sneezing.
It is therefore important to cover your mouth when you cough or sneeze, and to wash your hands regularly. Throw away used tissues immediately.
The outlook for acute bronchitis is very good. The condition is usually mild and self-limiting, which means that it gets better by itself without the need for medical treatment. The symptoms should pass within seven to ten days.
The outlook for pneumonia can vary widely, depending on a number of other factors that make the person more vulnerable to the effects of infection. These include:
- being over 65
- having a weakened immune system (the body’s natural defence against infection)
- having another serious health condition, such as chronic obstructive pulmonary disease (COPD), which is a general term describing a number of lung conditions that cause moderate to serious breathing difficulties
Depending on these risk factors, the likelihood of dying as a result of pneumonia can range from less than 1% to 50%.
Pneumonia can usually be treated with antibiotics. In mild cases, tablets (oral antibiotics) are usually recommended, with injections (intravenous antibiotics) being used in more serious cases.