New Delhi:
Neutralizing antibody levels decreased after six months in those who had been fully vaccinated against the coronavirus with Covishield, Covaxin and a mix of both – Covishield as the first dose and Covaxin as the second dose – with regard to the Omicron variant, a study conducted by the National Institute of Virology (NIV) in Pune.
However, the heterologous vaccination regimen of administering the first dose of Covishield, followed by the second dose of Covaxin, had produced a very good neutralizing response against Delta and other variants of concern, said Dr Pragya Yadav, a scientist at the NIV.
The research results were recently published in the Journal of Travel Medicine.
The study involved three cohorts — a heterologous group of 18 subjects who accidentally received the first dose of Covishield and the second dose of Covaxin in Uttar Pradesh and the other two groups consisting of 40 subjects who each received two doses of homologous Covishield or Covaxin.
“All three groups were closely monitored. When we analyzed the cohorts last June, the heterologous vaccination regimen of administering the first dose of Covisheid followed by the second dose of Covaxin showed a very good neutralizing antibody response against Delta and other variants. or Concern, compared to the other two cohorts,” Yadav said.
We re-analyzed them in December last year. A significant reduction in neutralizing antibody levels was observed in all cohorts related to Omicron, she said.
The study results so far have highlighted the need for a booster dose in the context of the Omicron variant, she added.
“The gradual shift of VoCs from Delta to Delta subline to Omicron, along with the observed decline in immunity after six months of vaccination, has sparked discussions about devising an innovative vaccination strategy. Current research findings contribute meaningfully to such discussions. Regardless of the findings of this study, longitudinal monitoring of breakthrough infections should remain a part of any surveillance system,” the study said.
India has started administering the precautionary doses of the COVID-19 vaccines from January 10 to healthcare and frontline workers and people aged 60 years and older with comorbidities.
The Union Ministry of Health recently removed the comorbidity clause, making anyone over the age of 60 eligible for the precautionary dose of the Covid vaccines.
The vaccination of children aged 12-14 has started from March 16.
(This story was not edited by DailyExpertNews staff and was generated automatically from a syndicated feed.)