Table 2.

Analysis for funnel plot asymmetry of studies reporting vaccine effectiveness, estimated by Egger's regression test.

	No. studies	coefficient	95% CI		p-value
Vaccine effectiveness on influenza visits among children	9	−0.78	−3.51	1.94	0.520
Vaccine effectiveness on influenza hospitalization among children	10	−3.05	−5.93	−0.18	0.040
Vaccine effectiveness on influenza visits among elderly subjects	3	−1.06	−16.41	14.29	0.541
Vaccine effectiveness on influenza hospitalization among elderly subjects	10	−0.52	−2.35	1.31	0.531