Table 2. Risk of bias according to The Cochrane Collaboration's 'Risk of bias' tool.

Publi-cation	Ran-dom sequ-ence genera-tion	Allo-cation conceal-ment	Blin-ding of partici-pants and personnel	Blin-ding of out-come assess-ment	Incom-plete out-come data	Selec-tive repor-ting	Other sources for bias	Sum-mary
Ser-retta et al. [2]	Unclear	Yes	Unclear	Unclear	Yes	Unclear	Co-authors employed by Astra-Zeneca	Unclear risk of bias
Bedog-netti et al. [9]	Yes	Yes	No	No	Yes	Unclear		High risk of bias
Fradet et al. [10]	Yes	Yes	Yes	Yes	Yes	Unclear	Funding by Astra-Zeneca	Low risk of bias
Saltz-stein et al. [4]	Yes	Yes	Yes	Yes	Yes	Unclear	Co-authors employed by Astra-Zeneca	Low risk of bias
Boc-cardo et al. [7]	Yes	Unclear	Yes	Yes	Yes	Unclear	Funding by Astra-Zeneca	Unclear risk of bias
Ozen et al. [11]	Unclear	Yes	No	No	Yes	Unclear		High risk of bias
Van Poppel et al. [12]	No	No	No	No	Yes	Unclear	Sponsored by Astra-Zeneca	High risk of bias
Tyrrell et al. [13]	Yes	Yes	Yes	Yes	Yes	Unclear	Funding by Astra-Zeneca. Co-authors employed by Astra-Zeneca	Low risk of bias
Wid-mark et al. [14]	Unclear	Unclear	No	No	Yes	Unclear		High risk of bias
Per-doná et al. [15] Di Loren-zo et al. [16]	Yes	Yes	No	No	Yes	Unclear		High risk of bias