Acute respiratory infections occur in the form of seasonal peaks and can be caused by a large number of different germs. They cause a high burden of disease and have a severe social impact during epidemics.
Acute respiratory infections can be caused by many different germs (e.g. influenza virus , Respiratory Syncytial Virus (RSV), Mycoplasma pneumoniae, parainfluenza virus, adenovirus, human metapneumovirus, etc.). The disease is mainly transmitted by inhaling contaminated airborne droplets or particles.
The symptoms often include coughing, fever, shortness of breath, runny nose, sore throat and generally feeling unwell. It is not possible to know which pathogen is responsible on the basis of the symptoms alone.
It is relatively common for complications to appear such as pneumonia or, more rarely, acute respiratory distress syndrome (ARDS). Especially in certain risk groups (the elderly, people with a chronic condition and infants), these acute respiratory infections can lead to a serious burden of disease and even death. The higher overall mortality during the winter months is partly due to acute respiratory infections.
Infections by certain germs often occur in the form of an annual epidemic. However, the moment of the peak of infections depends on the germ (see table).
Some common causes of acute respiratory infections are:
| Pathogen | Incubation period | Most affected age group | Symptoms and complications | Annual peak |
|---|---|---|---|---|
| Influenza virus | 1-5 days | Children < 15 years |
|
January — March |
| RSV | 2-8 days | Children < 2 years |
|
November — January |
| Para-influenza virus | 2–6 days | Children < 5 years |
In severe cases:
|
Peak in:
|
| Adenovirus | 2–14 days (5-6 days for acute respiratory infection) |
In people with a weakened immune system or young children, the infection can be serious:
|
Present all year round, but peak in November-March | |
| Mycoplasma pneumoniae | 1-4 weeks | School-age children and young adults |
In some cases, the progression of the disease can be severe:
|
Epidemic progression peaking every 4-7 years, usually in the winter months |
