Antibody neutralizing levels decreased after six months for those who had been fully vaccinated against the coronavirus by Covishield, Covaxin, and a combination of both -covishield and Covaxin – Covishield in the initial dose, and Covaxin in the 2nd dose, about Omicron variant the study conducted in collaboration with an institute called the National Institute of Virology (NIV) in Pune has revealed.
However, the regimen of heterologous vaccination administering the initial dose of Covishield and then another amount of Covaxin produced a highly effective neutralizing response to Delta and other variants of concern, Dr. Pragya Yadav, a scientist at the NIV, said.
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The study findings are recently published in the Journal of Travel Medicine.
The study was conducted on three groups — one heterologous group comprising 18 individuals accidentally given the first dose of Covishield and the dose for Covaxin located in Uttar Pradesh. The other two groups consisted of 40 people getting two doses each of the homologous Covishield and Covaxin.
“All the three groups were closely monitored. When we analysed the cohorts in June last year, the heterologous vaccination regimen of administering the first dose of Covisheid, followed by the second dose of Covaxin showed a very good neutralising antibody response against Delta and other Variants of Concern, as compared to the two other cohorts,” Yadav declared.
We examined them once more in December the previous year. The researcher said that significantly lower anti-neutralizing levels had been noted across all cohorts about Omicron.
The study results have highlighted the necessity of booster doses in the case in the context of the Omicron version, she explained.
“The gradual shift of VOCs from Delta to Delta-sub-lineage to Omicron, along with the observed waning of immunity post six months of vaccination, has prompted discourses around devising an innovative vaccination strategy.
The present investigation findings contribute meaningfully to such discussions. Regardless of the results of this study, longitudinal monitoring for breakthrough infections should remain a part of any surveillance system,” the study said.
India began to administer the preventive doses of the COVID-19 vaccination to frontline and healthcare workers and those who are 60 and above who have co-morbidities starting on January 10.
The Union health ministry was able to eliminate the comorbidity provision recently and made everyone over 60 years old eligible to get the pre-vaccination dose of Covid vaccines.
The vaccination for children between 12-and 14 years old began on March 16.
