Covaxin but lower than the breakthrough cases. However, those who had taken two doses of Covaxin had very low neutralizing titres demonstrating the waning immunity after three months of the second dose of Covaxin.
The findings of the study, conducted in February this year were published in the Journal of Infection on April 5. "The impact of the third wave of the pandemic in India, caused by Omicron, triggered us to study the effectiveness of Covaxin against this variant, Dr Pragya Yadav, a senior scientist at NIV Pune said. "We assessed the sera of naïve, recovered and breakthrough cases vaccinated with Covaxin for its neutralising ability against Omicron and other variants," Dr Yadav said.
Dr Pragya Yadav said the participants were categorised into three groups — The first group was of 52 COVID-19 volunteers vaccinated with 2 doses of Covaxin with an average age of 41.7 years, the second group was of 31 COVID-19 volunteers recovered cases vaccinated with 2 doses of Covaxin with average age of 41.7 years and the third group was of 40 of breakthrough cases after two-dose vaccination with Covaxin with an average age of 43.7 years.
The sera samples of naïve, recovered and breakthrough cases, were collected on average 97, 99 and 110 days, respectively. The breakthrough infection was found to occur on average 43 days after the second vaccination.