Publication status and disclosure gaps in a cohort of 71 clinical trials assessing the safety and efficacy of 3 COVID-19 vaccines developed by Chinese biopharmaceutical companies: An observational cohort study
Authors: Bruckner Till , Chen Yixuan , Cruz Carolina , Dike Christie Ebube , Chavarria Belen , Chen Shiyu , Dzidzornu Ernest Dela , Ringsten Martin 
Published: March 2024

Transparency shortcomings can undermine confidence in the safety and efficacy of vaccines. This study assesses the publication status and disclosure gaps in a cohort of 71 clinical trials assessing the safety and efficacy of 3 COVID-19 vaccines developed by Chinese biopharmaceutical companies that received a World Health Organization Emergency Use Listing (EUL) and have been marketed globally. We searched trial registries and the scientific literature to assess the completion status of those 71 trials, and to determine whether the outcomes of completed trials have been made publicly available.

The 71 trials in our cohort were initiated by sponsors headquartered in 17 different countries and aimed to enrol a total of 313,750 participants from across 27 countries. Out of those 71 trials, 49 trials (69%) had verifiably been concluded. We were unable to determine the completion status of the remaining 22 trials (31%) with certainty. Depending on whether those 22 trials were assumed to have been concluded or not, we found that between 13 completed trials (27%) and 35 completed trials (49%) remained unreported. At least 9 trials (13% of the total) had not made their results public more than one year post completion. According to registry data, between 36,498 people (12% of participants across all trials) and 89,224 people (28%) had participated in trials that had been concluded and whose outcomes remained unreported. There were no tabular summary results available on trial registries for any of the trials.

Our findings suggest that there are significant gaps in clinical trial governance, especially in countries that have only recently emerged as significant players in biomedical research. Maintaining global progress in clinical trial reporting will require legislators and regulators to adopt and effectively enforce clinical trial reporting requirements that reflect WHO best practices. The global clinical trial registry infrastructure needs to be strengthened so that users can reliably determine whether studies have been withdrawn, are still ongoing, or have been concluded.

Key messages

What is already known on this topic

The results of many clinical trials are only made public partially, after long delays, or not at all. Such disclosure gaps can make it difficult to assess the benefits and harms of treatments, and can undermine public trust in health interventions, including vaccines. In North America and Europe, disclosure has significantly improved in recent years.

What this study adds

Previous research in this field has overwhelmingly focused on clinical trials run by sponsors in North America and Europe that usually involved patients in these regions. Our study provides a global perspective on the problem, using a cohort of trials with high salience for global public health. More than 1.3 billion doses of 3 COVID-19 vaccines originally developed in China have been exported to dozens of countries worldwide. We assessed the publication status and disclosure gaps of 71 clinical trials of these vaccines. We found widespread research activity in newly emerging hubs of biomedical innovation. In total, sponsors from 17 different countries and participants from 27 countries were involved in relevant trials. None of the concluded trials had reported outcomes in line with global best practice standards set out by the World Health Organisation.

How this study might affect research, practice or policy

Clinical trial activity is increasingly becoming global. Our research points to significant gaps in clinical trial governance in many emerging hubs of biomedical innovation. Legislators and regulators in these countries should ensure that all clinical trial results are rapidly made public in line with World Health Organisation best practices to prevent the growth of gaps in the global medical evidence base. In addition, there is an urgent need to strengthen the global clinical trial registry infrastructure.