Vitamin C as a Supplementary Therapy in Relieving Symptoms of the Common Cold: A Meta-Analysis of 10 Randomized Controlled Trials

Table 2

Cochrane Collaboration’s tool for assessing the risk of bias for the comparison of vitamin C plus antiviral therapy with antiviral therapy alone.

Studies	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other bias
Fan 2016 [21]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Gao and Wang 2014 [22]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Li 2017 [23]	Low risk	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Wu 2015 [24]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Gao 2014 [25]	Low risk	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Sun 2016 [26]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Liu 2007 [27]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Li and Wang 2016 [28]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Liang 2016 [29]	Low risk	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear
Lin 2015 [30]	Unclear	Unclear	Unclear	Unclear	Low risk	Low risk	Unclear