Background: Pandemic events often trigger a surge of clinical trial activity aimed at rapidly evaluating therapeutic or preventative interventions. Ensuring rapid public access to the complete and unbiased trial record is particularly critical for pandemic research given the urgent associated public health needs. The World Health Organization (WHO) established standards requiring posting of results to a registry within 12 months of trial completion and publication in a peer reviewed journal within 24 months of completion, though compliance with these requirements among pandemic trials is unknown.
Methods: This cross-sectional analysis characterizes availability of results in trial registries and publications among registered trials performed during the 2009 H1N1 influenza, 2014 Ebola, and 2016 Zika pandemics. We searched trial registries to identify clinical trials testing interventions related to these pandemics, and determined the time elapsed between trial completion and availability of results in the registry. We also performed a comprehensive search of MEDLINE via PubMed, Google Scholar, and EMBASE to identify corresponding peer reviewed publications. The primary outcome was the compliance with either of the WHO's established standards for sharing clinical trial results. Secondary outcomes included compliance with both standards, and assessing the time elapsed between trial completion and public availability of results.
Results: Three hundred thirty-three trials met eligibility criteria, including 261 H1N1 influenza trials, 60 Ebola trials, and 12 Zika trials. Of these, 139 (42%) either had results available in the trial registry within 12 months of study completion or had results available in a peer-reviewed publication within 24 months. Five trials (2%) met both standards. No results were available in either a registry or publication for 59 trials (18%). Among trials with registered results, a median of 42 months (IQR 16-76 months) elapsed between trial completion and results posting. For published trials, the median elapsed time between completion and publication was 21 months (IQR 9-34 months). Results were available within 24 months of study completion in either the trial registry or a peer reviewed publication for 166 trials (50%).
Conclusions: Very few trials performed during prior pandemic events met established standards for the timely public dissemination of trial results.
Keywords: Clinicaltrials.gov; Ebola; H1N1; Non-publication; Pandemic; Publication bias; Trial registration; Zika.