Recovered Covid-19 Patients Highly Protected Against Delta Variants With Single Vaccine Dose: Study

COVID-19 recovered individuals with one or two doses of vaccine have relatively higher protection against Delta variant

New Delhi: Amid the fear of spread of Delta variant in the country, a study found that COVID-19 recovered individuals with one or two doses of vaccine have relatively higher protection in comparison to those administered either one or two doses of Covishield. 

The Indian Council of Medical Research (ICMR), National Institute of Virology, Pune, and Department of Neurosurgery, Command Hospital (Southern Command), Armed Forces Medical College conducted the study 'Neutralisation of Delta Variant with Sera of Covishield vaccines and COVID-19 Recovered Vaccinated Individuals', which is yet to be peer-reviewed. 

News agency PTI quoted the report stating that prior vaccination results in less severe disease against subsequent infection provide evidence that both humoral and cellular immune response play an important role in protection.  

"The high transmissibility associated with Delta variant led to second wave of the pandemic in India which affected millions of people. Besides this, variant of concerns have been reported to show lower neutralisation to several approved vaccines. This has led to breakthrough infections after completion of vaccination regimen," the study said. 

The joint study evaluated immune response in sera of the Covishield vaccinated individuals belonging to categories-- one dose vaccinated, two doses vaccinated, COVID-19 recovered plus one dose vaccinated, COVID-19 recovered plus two doses vaccinated and breakthrough COVID-19 cases. The results demonstrated that the breakthrough cases and COVID-19 recovered individuals with one or two dose of vaccine had relatively higher protection against Delta variant. 

"Prior vaccination results in less severe disease against subsequent infection provide evidence that both humoral and cellular immune response play an important role in protection," the study added.

The significant report has emerged at the time when B.1.617 lineage has created grave havoc in the country. It became worrisome when it further mutated to generate sub-lineages B.1.617.1 (Kappa), B.1.617.2 (Delta) and B.1.617.3. the World Health Organisation has described this sub-lineage as variant of concern as it dominated the other variants.