Patient advocacy groups in India are claiming that Bharat Biotech failed to ensure trial participants clearly understood their role in a study of the company’s Covaxin COVID-19 vaccine.

The allegations, which were made in an open letter to the Indian government, cite issues in the company’s informed consent process and reimbursement program. Allegations from the patient advocacy groups state that the language in the informed consent forms for the vaccine trial was difficult to understand, especially for the mostly illiterate study population.

Given that most trial participants were of low income and at a low education level, the advocacy groups argued that trial participants may not have clearly understood the ethics behind the monetary reimbursement Bharat provided for participation.

Bharat has denied the allegations, noting that it had followed regulatory rules for participants in its phase 3 vaccine trial. Bharat also stated that the reimbursement of $10 to each trial participant was provided for expenses and was approved by all institutional ethics committees at all sites.

This latest controversy involving Bharat’s COVID-19 vaccine follows other criticisms of the company, including the fact that the Indian government issued an emergency-use approval for its vaccine before phase 3 trials were completed. Also, Bharat reportedly failed to disclose a viral pneumonitis event in a phase 1 trial of Covaxin. Instead, the adverse event was made public after reports about it leaked to the Indian media in November.