Covaxin stock yet to land, delays CMC’s mixed vaccine trial

The researchers had subsequently got the mandatory clearance from the Clinical Trials Registry of India (CTRI) in this regard. However, the study is yet to take off, as the hospital is yet to receive Covaxin stock for the trial. 

The clinical trial is being conducted to find out if mixing the vaccines would enhance the overall efficacy. 

The consent form for the trial has been readied, he said. “It will have answers to all questions a volunteer is likely to ask. All doubts and questions regarding the trial, such as the type of vaccine used, efficacy, likely reactions and repercussions, protocol to be followed, etc. would be cleared on a one-to-one basis by the doctors part of the study,” Dr Rose added. 

Asked about possible adverse reactions, Dr Rose said all volunteers would be provided vaccine insurance by CMC Hospital, which would take care of the cost of any treatment in case any volunteer suffers reactions. 

Earlier, the National Institute of Virology (NIV), Pune, had conducted a study on 18 persons from Siddharth Nagar, Uttar Pradesh, who had received Covishield and Covaxin due to an inadvertent mix up. The study, which is yet to be peer-reviewed, found that mixing these vaccines resulted in better immunogenicity than both doses of the same vaccine. 

This study, on the other hand, would involve 500 volunteers – 200 would receive Covishield as the first dose and Covaxin as the second, while 200 others would have this order reversed. Of the remaining 100 volunteers, 50 would receive two doses of Covishield and the other 50 would receive two doses of Covaxin. 

Many countries, including the US, UK, Canada, Thailand and Vietnam, have already allowed combining vaccines. One study showed that mixing AstraZeneca’s vaccine (Covishield in India) with the vaccine developed by Moderna or Pfizer offered good protection against coronavirus infection.