Mix & Match of different vaccines is Safe and elicits robust antibody response: AIG Hospitals’ Study

Can different types of vaccines be administered with mix and match? This is an important question and was not being administered yet. So, if a person has taken let’s say one dose of Covishield, can he take another shot of Covaxine? And if he does that, what is the impact going to be?

AIG Hospitals, one of India’s largest tertiary care centres, along with researchers from the Asian Healthcare Foundation has done a similar study to determine the safety profile.

It mixed and matched COVISHEILD and COVAXIN along with checking the antibody response. For this purpose, 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 (~13%) participants were found to be seronegative, i.e., they didn’t have COVID-related antibodies,

“One of the incidental findings of the study is the seropositivity among our population. 87% of participants who didn’t get vaccinated and never tested positive for COVID had COVID-related antibodies. This means our population might have developed significant antibodies against the COVID because of the huge Delta wave that we endured,” said Dr D Nageshwar Reddy, Chairman, AIG Hospitals.

The 44 participants were divided into two four groups. Group 1: First Dose COVIDSHEILD + Second Dose of COVISHEILD, Group 2: First Dose of COVAXIN + Second Dose of COVAXIN

Group 1 and 2 were the homologous vaccine groups in which the same vaccine have been given and relevant antibody titers were checked.

Group 3: First Dose of COVISHEILD + Second Dose of COVAXIN, Group 4: First Dose of COVAXIN + Second Dose of COVISHEILD. Group 3 and 4 were the heterogeneous vaccine groups in which different vaccines were given and antibody titers were checked.

All these 44 participants were followed for 60 days to see if there’re any adverse effects. The study conclusively showed that mixing vaccines are absolutely safe as none of the participants developed any adverse effect.

“The most important finding of the study was that the Spike-protein neutralizing antibodies found in the mixed vaccine groups were significantly higher than the same-vaccine groups,” Dr Reddy said.

Dr Reddy, who is also among the researchers, involved in the study said “Spike-protein neutralizing antibodies are the ones which kills the virus and reduces the overall infectivity. We 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 same vaccine.”