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Table 2 Comparison of HPV vaccine clinical study reports with trial register entries and journal publications: inclusion of protocol and reporting of trial design aspects including PICO criteria

From: Benefits and harms of the human papillomavirus (HPV) vaccines: comparison of trial data from clinical study reports with corresponding trial register entries and journal publications

Inclusion of protocol and reporting of trial design aspects including PICO criteriaClinical study reports: N = 24Trial register entries: N = 24Publications: N = 23
Protocol
 Included in study document10 (42%)0 (0%)2 (9%)
  - Prespecified outcomes10 (100%)Not applicable2 (100%)
  - Included statistical analysis plan10 (100%)Not applicable2 (100%)
Reporting of six major design-related biases defined by the Cochrane Handbooka
 Randomization method was explicitly specified24 (100%)0 (0%)22 (96%)
 Allocation concealment was explicitly specified24 (100%)0 (0%)17 (74%)
 Blinding of outcome assessors was explicitly specified24 (100%)23 (96%)17 (74%)
 Blinding of personnel was explicitly specified24 (100%)11 (46%)12 (52%)
 Blinding of participants was explicitly specified24 (100%)23 (96%)12 (52%)
 Loss to follow-up (attrition) was explicitly accounted for24 (100%)20 (83%)23 (100%)
Population
 Specified inclusion criteria24 (100%)24 (100%)22 (96%)
  - Mean number of inclusion criteria7.05.84.0
 Specified exclusion criteria24 (100%)24 (100%)20 (87%)
  - Mean number of exclusion criteria17.811.75.0
Intervention
 Specified HPV vaccine antigens24 (100%)18 (75%)23 (100%)
 Specified HPV vaccine adjuvants24 (100%)8 (33%)23 (100%)
 Specified dose24 (100%)6 (25%)21 (91%)
Comparator
 Specified content24 (100%)8 (33%)23 (100%)
 Specified dose24 (100%)6 (25%)21 (91%)
 Reported active comparator as a ‘placebo’b14 (58%)13 (54%)17 (74%)
Outcomes
 Primary outcomes explicitly specified24 (100%)24 (100%)18 (78%)
  - Mean number of primary outcomes1.63.51.2
 Secondary outcomes explicitly specified24 (100%)24 (100%)14 (61%)
  - Mean number of secondary outcomes8.813.03.2
  1. aCochrane Handbook: http://training.cochrane.org/handbook
  2. bActive comparators included amorphous aluminium hydroxyphosphate sulphate (AAHS), aluminium hydroxide (Al[OH]3), carrier solution and hepatitis vaccines (Aimmugen™, Engerix-B™, Havrix™ and Twinrix Paediatric™)