Two doses of Covishield vaccine protected adult population from Covid-19 in Chennai: Study

A community-based cohort study in Chennai estimated 61 percent of the vaccine effectiveness of two doses of Covishield vaccine against delta variant infection in people over 45 years of age. The study was conducted by ICMR-National Institute of Epidemiology and Greater Chennai Corporation from May to September 2021 in a selected geographic area in the city.

Vaccine efficacy against Covid-19 in the age group 45 years and older was 61.3 percent at least two weeks after receiving the second dose of Covishield. Covishield’s two-dose coverage in the 18+ and 45+ age groups was 18 percent and 31 percent, respectively. Genomic analysis of 74 of the 90 ‘aliquots’ collected from the 303 COVID-19 positive individuals in the age group of 45 showed delta variants and their sublines.

“We have demonstrated the effectiveness of two doses of the Covishield vaccine against the delta variant in the general population of Chennai. We recommend similar future studies, taking into account emerging variants and newer vaccines,” the report said.

“We may need similar population-level VE studies in the context of changing variants and newer vaccines and boosters,” it added.

“The databases for disease surveillance (including hospitalization) and vaccination programs are currently not linked, limiting the possibilities for systematic periodic analysis of vaccine effectiveness. Effective links between databases help countries such as the UK to report real-time vaccine effectiveness analyses,” the report said.

“We recommend linking the disease surveillance and vaccination databases at the national and state levels to enable regular, in-depth, real-time analysis of vaccine effectiveness. Our study supports the need to ensure high vaccination coverage with two doses to maintain immunity against Covid-19 infection,” the report said.

published on

June 19, 2022

Leave a Comment

Your email address will not be published.