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BMJ. 2014 May 16;348:g3058. doi: 10.1136/bmj.g3058.

Non-publication and delayed publication of randomized trials on vaccines: survey.

Author information

1
Department of Medicine and Aging Sciences, University of Chieti, Via dei Vestini 5 66013 Chieti, Italy CeSI Biotech, Via Colle dell'Ara, Chieti, Italy lmanzoli@post.harvard.edu.
2
Department of Medicine and Aging Sciences, University of Chieti, Via dei Vestini 5 66013 Chieti, Italy Local Health Unit of Pescara, Italy.
3
Division of Clinical Epidemiology and Biostatistics, Institute of Social and Preventive Medicine, University of Bern, Switzerland Division of International and Environmental Health, Institute of Social and Preventive Medicine, University of Bern, Switzerland.
4
Department of Medicine and Aging Sciences, University of Chieti, Via dei Vestini 5 66013 Chieti, Italy CeSI Biotech, Via Colle dell'Ara, Chieti, Italy.
5
Department of Public Health and Infectious Diseases, Sapienza University of Rome, Italy.
6
Stanford Prevention Research Center, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA, USA.

Abstract

OBJECTIVE:

To evaluate the extent of non-publication or delayed publication of registered randomized trials on vaccines, and to investigate potential determinants of delay to publication.

DESIGN:

Survey.

DATA SOURCES:

Trials registry websites, Scopus, PubMed, Google.

STUDY SELECTION:

Randomized controlled trials evaluating the safety or the efficacy or immunogenicity of human papillomavirus (HPV), pandemic A/H1N1 2009 influenza, and meningococcal, pneumococcal, and rotavirus vaccines that were registered in ClinicalTrials.gov, Current Controlled Trials, WHO International Clinical Trials Registry Platform, Clinical Study Register, or Indian, Australian-New Zealand, and Chinese trial registries in 2006-12. Electronic databases were searched up to February 2014 to identify published manuscripts containing trial results. These were reviewed and classified as positive, mixed, or negative. We also reviewed the results available in ClinicalTrials.gov.

MAIN OUTCOME MEASURES:

Publication status of trial results and time from completion to publication in peer reviewed journals.

DATA SYNTHESIS:

Cox proportional hazards regression was used to evaluate potential predictors of publication delay.

RESULTS:

We analysed 384 trials (85% sponsored by industry). Of 355 trials (404,758 participants) that were completed, 176 (n=151,379) had been published in peer reviewed journals. Another 42 trials (total sample 62,765) remained unpublished but reported results in ClinicalTrials.gov. The proportion of trials published 12, 24, 36, and 48 months after completion was 12%, 29%, 53%, and 73%, respectively. Including results posted in ClinicalTrials.gov, 48 months after study completion results were available for 82% of the trials and 90% of the participants. Delay to publication between non-industry and industry sponsored trials did not differ, but non-industry sponsored trials were 4.42-fold (P=0.008) more likely to report negative or mixed findings. Negative results were reported by only 2% of the published trials.

CONCLUSIONS:

Most vaccine trials are published eventually or the results posted in ClinicalTrials.gov, but delays to publication of several years are common. Actions should focus on the timely dissemination of data from vaccine trials to the public.

PMID:
24838102
[Indexed for MEDLINE]
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