Table 1.

Influenza seasonal characteristics in Hefei, China, 2010–2015.

Index	Phase	Err.phase	Amplitude(95%CI)	Err.amplitude	Peek time	Oddsf
	(95%CI)	(95%CI, E-03)		(95%CI, E-6)	(week)
Annual
flu%a	1.254 (−1.200,1.930)	6.642 (4.475,12.055)	0.0427 (0.008,0.089)	154.81 (46.493,239.070)	10.409	40.01%
annflu%b	1.524 (0.798,1.930)	1.100 (0.669,1.659)	0.0110 (0.002,0.023)	5.896 (1.853,11.473)	12.656	40.94%
ILI ratec	−0.149 (−0.694,2.011)	0.875 (0.705,1.069)	0.0066 (0.005,0.008)	0.215 (0.100,0.463)	−1.236	34.86%
ILI × flu%d	0.653 (−0.963,1.404)	0.492 (0.263,0.742)	0.0021 (0.000,0.005)	0.296 (0.067,0.579)	5.424	43.30%
P&Ie	1.491 (1.280,1.704)	0.315 (0.264,0.383)	0.0051 (0.003,0.007)	0.524 (0.398,0.711)	12.380	43.58%
Semi-annual
flu%	0.494 (−2.936,2.847)	13.035 (10.356,16.242)	0.0285 (0.0054,0.0604)	172.250 (109.78,252.68)	2.051
annflu%	1.056 (−0.948,2.290)	2.440 (1.530,3.604)	0.0076 (0.0016,0.0169)	6.177 (2.380,12.007)	4.385
ILI rate	0.063 (−2.270,2.360)	0.910 (0.763,1.059)	0.0035 (0.0007,0.0075)	0.840 (0.584,1.116)	0.263
ILI × flu%	0.871 (−2.913,2.952)	0.682 (0.505,0.883)	0.0016 (0.0003,0.0038)	0.472 (0.256,0.739)	3.615
P&I	0.657 (0.088,1.333)	0.725 (0.643,0.822)	0.0040 (0.0022,0.0058)	0.533 (0.411,0.690)	2.727

^aFlu% refers to the proportion of flu positive cases among the number of cases tested per week.

^bAnnflu% refers to the proportion of flu positive cases among the sum of total flu positive cases collected per year.

^cILI rate refers to the proportion of ILI cases among the total outpatient patients.

^dILI × flu% refers to the flu% corrected with the product of flu% and ILI rate.

^eP&I refers to the proportion of the death caused by pneumonia and influenza among the total citizen population.

^fOdds refers to the proportion of the amplitude of semi-annual cycle among the sum of the amplitude of both annual and semi-annual cycle.