Mixing shots safe and effective: Study

NEW DELHI: After analysing the accidental mixing of Covishield and Covaxin vaccine shots in 18 people in an Uttar Pradesh village, the Indian Council of Medical Research (ICMR) has concluded in a pre-print study that the combination of the two Covid-19 vaccines elicits a better immune response than two jabs of the same vaccine.

In May, 20 villagers in a government-run hospital in UP’S Siddharthnagar district were inadvertently administered the second dose of Covaxin after the first dose of Covishield after a gap of six weeks. Of the 20, 18 agreed to be part of the study. Among them, 11 were men with a median age of 62 years. A comorbid condition (hypertension) was reported in one individual. “We compared the safety and immunogenicity profile of them against that of individuals receiving either Covishield or Covaxin… Immunogenicity profile against Alpha, Beta and Delta variants in the heterologous group was superior; IGG antibody and neutralising antibody response of the participants was also significantly higher compared to that in the homologous groups,” researchers said in the paper, which is yet to be peer-reviewed. While the findings could benefit the immunisation programme, there is a need for a randomised controlled trial to further corroborate the findings.

“A slew of studies suggests that mixing vaccines provokes potent immune responses, but scientists still want answers on real-world efficacy and rare side according to Nature.

According to the study, none of the participants enrolled in the study had any serious adverse event following immunisation (AEFI) within 30 minutes of inoculation with the first or second dose.