CMC completes 28 days of mixed vaccine study

The first phase of the mixed vaccine study undertaken by CMC hospital has reached the analysis stage, according to the study’s principal investigator Dr Winsley Rose.

The study analyses how covaxin and covishield vaccines interact in the human body when candidates who took the covishield vaccine were given covaxin as the booster dose and vice versa.

It may be recalled that CMC undertook the study when the virus was highly prevalent during the second wave in 2021. A total of 200 candidates were selected for the study. There was a delay because it was hard to get candidates who had taken both doses of covaxin.

Dr Rose said, “We completed the initial 28 days of study. We expect to complete the more detailed 6-month study in a day or two for those who were vaccinated with Covishield. The initial study assessed how much antibodies were developed in the host’s body after they were given the booster dose of the other vaccine.”

A similar trial will be undertaken for participants who took both doses of covaxin and were given covishield as the booster dose.

“However, the analysis after the six-month period which will end in June this year, will take another few weeks for the investigators to understand fully how the booster doses work in the host’s bodies,” he added.

In July 2021, the Subjects Experts Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO) had recommended that a study in this regard must be conducted at CMC. A month later, the Drugs Controller General of India (DCGI) granted permission.

However, this study by CMC is different from the one conducted last year by the Indian Council of Medical Research (ICMR). It had analysed an ‘accidental’ mixing of covishield and covaxin in Uttar Pradesh, and concluded the incident “safe and effective”.