Table 2.

Results of sensitivity analysis by the general liner model (GLM).

Variable	RR	95% CI	P value
Age
<45	Reference
≥45	0.553	0.451–0.869	0.005
Residence
Local	Reference
External	0.890	0.657–1.231	0.471
Cluster case
Yes	Reference
No	1.273	0.959–1.704	0.107
Chest congestion
Yes	Reference
No	0.444	0.289–0.978	0.043
Leucocyte count
<4 × 109/L	Reference
≥4 × 109/L	1.177	0.850–1.665	0.344

RR, relative risk; 95%CI, 95% confidence interval.