Government expert panel recommends conducting trials on mixing Covishield, COVAXIN
The Subject Expert Committee (SEC) on COVID-19 of the Central Drugs Standard Control Organization (CDSCO) has given its go-ahead for conducting clinical trials involving the mixing and matching of Covishield and COVAXIN vaccine doses. The expert panel on Thursday recommended granting permission to the Christian Medical College (CMC), Vellore in Tamil Nadu for carrying out the trials on mixing of these vaccine doses.
The SEC, amid increasing discussions on the supposed greater efficacy of mixing different COVID-19 vaccines, deliberated in detail on the application moved by CMC, Vellore for trials on the interchangeability of Covishield and COVAXIN doses. This will be India's first-ever mix-and-match study involving the two vaccines. The SEC met on Thursday to discuss issues concerning the updating of the current COVID-19 protocol being followed.
"The expert panel discussed a study protocol by CMC, Vellore for interchangeability of COVAXIN and Covishield vaccines and gave its green signal," said a senior government official. The trials will be reportedly conducted among 300 volunteers—split into two groups. While the first group takes Covishield as the first dose and COVAXIN as the second, the other group will receive COVAXIN first and Covishield later.
"The SEC, after detailed deliberations, recommended granting permission to CMC, Vellore, for conducting the phase-4 clinical trial covering 300 healthy volunteers for mixing of COVID-19 vaccines COVAXIN and Covishield," a source told India.com. "The aim of the study is to assess whether a person can be given two different vaccine shots—one each of Covishield and COVAXIN—to complete the inoculation course," the source said.
The mix-and-match of COVID-19 vaccines is a method of immunization involving the administration of two doses from different makers. Many experts believe giving two vaccines developed on different platforms would produce a better immune response, offering greater protection against COVID-19. However, some feel it's not a good idea as these vaccines are manufactured differently and the end result may not really be favorable.
This mix-and-match vaccination strategy is called heterologous prime-boost immunization, which has reportedly been used in vaccine development to fight Ebola and experimental vaccines for HIV/AIDS, too. Traditionally, however, homologous prime-boost vaccination, involving the administration of doses of the same vaccine, is followed. But some studies have shown that prime-boost with different jabs comprising the same antigens could trigger better immune responses than homologous prime-boost.
To note, Covishield—based on the viral vector platform—has been developed by Oxford-AstraZeneca and is manufactured by Pune-based Serum Institute of India (SII). COVAXIN—based on inactivated whole virion platform—has been developed by Hyderabad-based Bharat Biotech in partnership with the Indian Council of Medical Research (ICMR). Covishield, COVAXIN, and Russia's Sputnik V are the vaccines currently being administered as part of India's vaccination drive.