3.1 Participant characteristics
The average age of participants was 10.2 years with slightly more males than females represented (Table 1). More than half of the participants reported symptoms that met the definition of an ILI. Cough, malaise, and nasal congestion were reported in over 80% of participants while runny nose and sore throat were reported in more than 70%. Myalgia was the least common symptom and was reported in 28% of participants. Slightly more than half of the children (52.4%) were vaccinated against influenza. Influenza was confirmed by RT-PCR in 710 (30.0%) specimens (influenza A: n=443; influenza B: n=263; dual detection: n=4).