The mixing of vaccines didn’t point to any safety issues, the study said.
As part of the study, a total of 330 healthy volunteers who were not vaccinated and had no history of COVID infection were selected and screened for SARS-CoV-2 antibodies for the study.
Out of these 330, 44 or 13% participants were found to be seronegative, or didn’t have COVID-related antibodies, indicating high level of seropositivity.
The 44 participants were divided into four groups. Two groups were homologous in which the same vaccine was given as two doses.
The third and fourth groups were the heterogenous vaccine groups in which they received first dose as Covishield and second as Covaxin; and the fourth received first of Covaxin and second dose of Covishield.
Group 3 and 4 were the heterogenous vaccine groups in which different vaccines were given and antibody titers were checked.
The study found that when the first and second dose are of different vaccines, the Spike-protein antibody response is four times higher compared to two-dose of the same vaccine.
“Spike-protein neutralizing antibodies are the ones which kill the virus and reduce the overall infectivity,” said Dr. D Nageshwar Reddy, Chairman of AIG Hospitals.
All the 44 participants were followed for 60 days to see if there’re any adverse effects.
“The study conclusively showed that mixing of vaccines is absolutely safe as none of the participants developed any adverse effects,” AIG Hospitals said.
AIG Hospitals said it has shared the data from the study with the Indian Council for Medical Research (ICMR) to be considered as a reference study while deciding on the “Prevention” doses starting January 10.