Serum Institute of India chairperson Cyrus Poonawalla on Friday said he was against the mixing of different coronavirus vaccine doses, reported the Hindustan Times. The Serum Institute produces the Covishield vaccine.
“If cocktail vaccines are administered and if the result is not good, then SII [Serum Institute of India] may say that another vaccine was not good, vice versa, the other company might say that since you mixed Serum’s vaccine, it did not give desired results,” Poonawalla said, adding that it was wrong to mix vaccines.
He said that mixing of doses was “not at all proven” in field trials, reported India Today.
Poonawalla, however, later clarified his comments. “For those who have been administered the first dose of a particular vaccine and in case of the unavailability of the second dose of the same, as an alternative, another vaccine can be administered,” he said.
He added: “That said, the efficacy and the immunogenicity of the combination are dependent on the ongoing studies conducted by regulators.”
Poonawalla’s comments came after the Drugs Controller General of India approved a study on mixing Covishield and Covaxin vaccines. Covaxin is manufactured by Bharat Biotech.
In July, the Central Drugs Standard Control Organisation’s Subject Expert Committee had recommended allowing Christian Medical College in Tamil Nadu’s Vellore city to conduct the study.
Last week, an Indian Council of Medical Research study had found that mixing two vaccine doses was not only safe but produced a better immune response.
The study involved three groups: 18 people in Uttar Pradesh who were accidentally administered one dose of Covishield and a second dose of Covaxin in May, 40 people who got both doses of Covishield, and an equal number of those who were inoculated with both doses of Covaxin.
Currently, the government has not approved the mixing of two different Covid-19 vaccines. The ICMR study has not been peer reviewed either. It was published on medRxiv, an online journal for unpublished reports on medical sciences.
Meanwhile, India on Friday recorded 40,120 cases of Covid-19 in the past 24 hours, taking the cumulative tally to 3,21,17,826 since the pandemic began in January last year. The toll rose to 4,30,254 with the country reporting 585 fatalities in the past day.