Clinical Overview of Influenza
In all patients, the flu can take its toll.
- On average, influenza affects an estimated 5 to 20 percent (16-62 million) of the United States population annually.2,36
The severity of influenza is unpredictable and often underestimated.
- The annual range of deaths associated with seasonal influenza spans 3,000 to 49,000 (1976-2007).26
- A study of influenza type 2009 H1N1 revealed the mean age at death of laboratory-confirmed influenza was 37.27
Flu is a major cause of hospitalization:28
Symptoms of influenza
Influenza is spread from person to person through respiratory droplets that are dispersed when an infected person coughs or sneezes in close proximity to someone who is not infected.2
Adults can be infectious from 1 day before onset of symptoms to 5-7 days after illness onset.2
Influenza is more infectious in children than adults.29
- Children can shed earlier, before illness begins, and for longer once illness starts.
- Viral shedding can occur for up to 21 days (median 7-8 days) in children.
Uncomplicated influenza is characterized by abrupt onset of signs and symptoms that may include17:
- Sore throat
- Chest discomfort, cough
- Some people may have vomiting and diarrhea, though this is more common in children than adults.4
- Most people who get influenza will recover in a few days to less than 2 weeks.4
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