The National Technical Advisory Group on Immunisation (NTAGI) needs adequate scientific data to make a recommendation on the mixing of COVID-19 vaccines, the government said on March 29.

The Central Drugs Standard Control Organization (CDSCO) has granted permission to the Christian Medical College, Vellore to conduct the phase-IV study with Covishield and Covaxin to compare the immunogenicity of mixed vaccine regimen and to Bharat Biotech for a phase-2 clinical trial to evaluate the immunogenicity and safety of Covaxin with BBV154 (Adenoviral Intranasal COVID-19 vaccine), Minister of State for Health said.

"Adequate scientific data is required for NTAGI to make a recommendation on mixing of COVID-19 vaccines, at present this information is not available," the minister said in a written reply in the Rajya Sabha.

She was responding to a question on whether the government is considering mixing COVID-19 vaccines based on heterologous strategies conducted earlier for other diseases, to induce combined antibody and cell-mediated immune responses resulting in stronger and long-lasting immunity and if any study has been undertaken in this regard.