Seasonality is a well-known phenomenon in public health. Climatic changes (temperature, humidity, precipitation) can affect the development and transmission of certain pathogens. They also influence life style and behaviors, which can play a role in the transmission of certain diseases. This is particularly true in the summer, a season often associated with specific respiratory tract infections in children and adults.
Respiratory tract infections are not limited to winter because:
- Important temperatures variations (air-conditioning) can be associated with rhinitis, throat infections etc.
- Streptococcus pneumonia is more contagious in summer than in winter
- Frequentation of swimming pools increases the risks of otitis externa (according to WHO, Staphylococcus aureus is frequent in recreational waters, especially when there is a high density of bathers)
- Rhinoviruses are the most frequently isolated viruses in the summer
- Most viruses thrive under warm, humid conditions, while they can be dormant in winter (e.g. rhinoviruses, influenza, enteroviruses etc.).
- In COPD patients, there is a second peak of acute exacerbation episodes in summer
- Seasonal rhinitis have soared in recent decades and could affect today as much as 10% of the adult population in industrialized countries
Carriage of bacterial in nose swabs detected by real-time PCR (both children & adults) (%)