Table 2

Phrases used to describe the control arm (proportion of trials)

Phrases usedICFCSRRegisterPublication
SynopsisMain bodyProtocolAbstractFull text
Placebo5/55/55/55/54/54/55/5
 ‘Placebo’ or ‘matching placebo’5/55/55/55/54/54/55/5
 ‘Placebo (which is a dose that contains no active ingredients)’4/50/50/50/50/50/50/5
 ‘Placebo … an inactive substance’ or ‘placebo … an inactive solution’3/50/50/50/50/50/50/5
 ‘Placebo HPV Vaccine’3/50/50/50/50/50/50/5
Placebo with adjuvant0/51/55/54/50/50/55/5
 ‘Placebo with adjuvant’0/50/52/50/50/50/50/5
 ‘Aluminum adjuvant placebo’ or ‘Alum-placebo’ or ‘aluminum-placebo’ or ‘aluminum-containing placebo’ or ‘visually indistinguishable aluminum-(or ‘AAHS’)containing placebo’ or ‘matched aluminum-placebo’ or ‘placebo (aluminum adjuvant)’0/51/54/54/50/50/55/5
Placebo with adjuvant and dose3/53/53/55/50/50/50/5
 ‘Placebo’-containing 225 ug of aluminium adjuvant0/52/51/54/50/50/50/5
 ‘Placebo’ or ‘matched placebo’-containing Merck standard aluminium diluent (225 mcg alum), with or without mention of normal saline0/51/50/52/50/50/50/5
 ‘Placebo’-containing 225 mcg of aluminium as AAHS, with or without mention of normal saline0/51/52/50/50/50/50/5
 ‘Inactive solution (containing aluminium 225 mcg/dose)’3/50/50/50/50/50/50/5
  • Normal saline = USP (NaCl 0.9%).

  • AAHS, amorphous aluminum hydroxyphosphate sulfate; CSR, clinical study report; ICF, informed consent form.