Single vaccine dose enough to shield recovered Covid patient against Delta variant: ICMR study

Mangalore Today News Network / NDTV

New Delhi, Jul 03, 2021: People who have recovered from Covid-19 and received one or both doses of vaccine exhibit higher protection against the Delta variant as compared to individuals who have taken one or two doses of Covishield, a new study by the Indian Council of Medical Research (ICMR) has found.

 

The study shows that humoral and cellular immune response plays an important role in protection against the Delta variant of the coronavirus, which is more transmissible and virulent than other mutated strains.

“The findings of the study demonstrated that the breakthrough cases and the Covid-19 recovered individuals with one or two dose of vaccine had relatively higher protection against Delta variant in comparison to the participants who were administered either one or two doses of Covishield. 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 ICMR report stated.

The study assessed neutralizing antibody response of individuals immunized with Covishield (first dose and second dose), Covid-19 recovered individuals who were vaccinated (first dose and second dose) and breakthrough infections (due to Kappa and the Delta variant). A neutralizing antibody is responsible for defending cells from pathogens and blocking infections by neutralizing any effect it has biologically.Findings show that even one dose of vaccine in a Covid-recovered patient is enough to shield against a coronavirus re-infection and offers protection against newly emerging variants because they have a naturally high neutralizing antibody count.Moreover, the neutralizing antibodies in breakthrough cases and Covid-recovered individuals with one or two doses of vaccine had relatively higher protection against Delta variant in comparison to the participants who were administered either one or two doses of Covishield.

"Long-term follow-up of participants could help understand the impact of natural infection and vaccination on long-term protection from SARS-CoV-2 offered by Covishield. It is important to track the breakthrough infections to look for unexpected changes," it added.

According to the study, currently available vaccines induce robust humoral and cellular immune response against the coronavirus. But in the wake of the Delta variant infecting people even after two shots of Covid-19 vaccines, it is "crucial to continuously evaluate vaccine-induced humoral immunity to SARS-CoV-2, immunity following natural infection, and the phenomenon of breakthrough infection to understand the immune escape" due to emerging variants of concern (VOCs).

"Monitoring of breakthrough infection would make us understand the impact of new variant or VOC on escape of vaccine induced immunity. Data has shown again and again that if the individuals get infected post vaccination, had been protected from severe disease,” said the study.

Courtesy:India Today