The dwindling participant interest in Covid-19 vaccine human trials poses a risk of delaying the process.
While the nation hopes that the wait for a Covid-19 vaccine will soon be over, the process may take longer than expected. The vaccine trials are facing hiccups in India, as the number of people stepping forward to participate in the trials is declining.
Bharat Biotech vaccine Covaxin is currently under phase 3 of the human clinical trials stage across the country. While the vaccine-makers have applied for an emergency use authorisation approval from the Indian drug authorities, the trial is moving slowly as a lesser number of participants are willing to be a part of the trial process.
“When a healthy volunteer registers with us, as ethics follow, we have to tell them that we will not know if they have been administered a vaccine or a placebo. People are now hesitant to take a placebo. They say why should we volunteer for a 50-50 chance of having taken a vaccine? They feel that the Covid-19 vaccine will soon in available in India, in a matter of weeks,” said Dr Sanjay Rai, lead investigator of the trials and Professor of Community Medicine at AIIMS, New Delhi.
“Therefore, the refusal rate of participants has increased. For phase 3, the refusal rate is about 70-80 per cent. In comparison, the refusal rate during phase 1 was less than 10 per cent, even when not much was known about the safety or the efficacy of the vaccines for Covid-19 in the world,” he said.
Dr Rai said that phase 1 had 4,500 applicants for 100 volunteer spots; phase 2 had 4,000 volunteers for 50 places. In phase 3, there is a requirement of 2,500 volunteers. However, only about 200-300 people have come forward to participate in the trial.
Currently, Bharat Biotech is conducting clinical trials with over 22,000 volunteers at 18 sites across the country.
The authorities at the clinical site have planned to create awareness among people through advertisements, emails and cold calling. There is a chance that other Covid-19 vaccine trials at different stages could also face similar issues.
Recently, the Covid-19 vaccine being developed by Pune-based Gennova Biopharma received approval for phase 1 trials in the country. Hyderabad-based Biological E limited’s vaccine candidate is at phase 1/2 trial stages. Sputnik V vaccine phase 2/3 human trials are also currently underway in India.
Meanwhile, the Centre has prepared a detailed guideline for mass Covid-19 vaccination. The Union health ministry has also directed the states to prepare for adverse events post Covid-19 vaccination.