HYDERABAD: Mixing of vaccines is not only safe but also effective against Covid-19. According to a study conducted by AIG Hospitals and Asian Healthcare Foundation, the spike-protein neutralising antibodies found in the mixed vaccine group are at least four times higher than in the same-vaccine group. The study titled “Safety and Immunogenicity of Mix-Match of vaccines -- Covishield and Covaxin -- a pilot study” is in pre-print in Research Square journal.
At the outset, a total of 330 healthy volunteers who were not vaccinated and had no history of Covid-19 infection were screened during the study. They were then screened for SARS-CoV-2 antibodies and it was found that out of these 330, only 44 (13 per cent) participants were seronegative as they had no Covid-19 related antibodies.
It was on these 44 participants a further analysis of mix-match vaccines was done, with 21 receiving the same set of vaccines and 23 receiving the mix-match vaccines. All these 44 participants were under observation for 60 days to see if there were any adverse effects.
The study conclusively showed that mixing of vaccines was absolutely safe as none of the participants developed any adverse effects. The most important finding was that the spike-protein neutralising antibodies found in the mixed vaccine groups were significantly higher than the same-vaccine groups.
‘Antibody response four times higher in mixed vax’
Dr. D Nageshwar Reddy, Chairman, AIG Hospitals, who is also among the researchers involved in the study, said “Spike-protein neutralising antibodies are the ones which kill the virus and reduce the overall infectivity. We found that when the first and second doses are of different vaccines, the antibody response is four times higher compared to two-dose of the same vaccine.”
He further observed that the findings of the pilot study were more important when considering the third booster dose to be given in the coming week. “The concept of a booster is to elicit robust antibody response and help in killing the virus. Mixed doses can certainly boost these spike-protein neutralising antibodies and will enhance the vaccines’ effectiveness even against the Omicron variant,” Dr. Reddy added.
The AIG Hospitals has now shared the data from the study with the ICMR to be considered as a reference study while deciding on the “prevention” doses, which are to be administered from January 10.