Table 3.

Clinical and epidemiological characteristics associated with different viruses responsible for Sentinelles influenza-like illnesses (defined as a sudden onset of fever >39°C with myalgia and respiratory signs)

	Influenza virus	Respiratory syncytial virus	Human metapneumo-virus	Human rhinovirus
Cough	+ +	+ +	+ +
Headache	+	–	–
Rhinorrhoea	+	+		+
Dyspnoea	–	+ +
Conjunctivitis	+
Period of onset of symptoms
Before influenza epidemic	– – –	+++	+	+++
During influenza epidemic	a	a	a	a
After influenza epidemic	– – –		+ +	+
Age group (years)
<5	–	+++	+++	+
5–14	+	+		–
15–29
30–44	a	a	a	a
45–64		+ + +	+ +
≥65		+ + +	+ + +
Influenza vaccination (for current season)	–

Adjusted OR significantly >1: ‘+’ for 1 < OR < 2; ‘+ +’ for 2 ≤ OR < 3; ‘+ + +’ for OR ≥ 3. Adjusted OR significantly <1: ‘–’ for 0.5 < OR < 1; ‘– –’ for 0.3 < OR ≤ 0.5; ‘– – –’ for OR ≤ 0.3.

^aReference group.