Trial	Generation of allocation sequence	Allocation concealment	Blinding	Inclusion of all randomized participants
Bock 1990	Unclear	Unclear	Single	Adequate
Eder 2003i	Unclear	Unclear	Double	Adequate
Eder 2003ii	Unclear	Unclear	Double	Adequate
Ehrlich 2003	Adequate	Unclear	Double (first 2 doses) and open (for dose 3)	Adequate
Girgsdies 1996	Unclear	Unclear	Double	Adequate
Harabacz 1992	Unclear	Unclear	Double	Adequate
Immuno 1996	Adequate	Adequate	Double	Adequate
Loew‐Baselli 2006	Unclear	Unclear	Single (participants)	Adequate
Pavlova 1999	Unclear	Unclear	Not mentioned	Inadequate for efficacy adequate for safety
Schoendorf 2007	Unclear	Unclear	Open	Adequate
Schöndorf 2007	Unclear	Unclear	Open	Inadequate for efficacy and unclear for safety