As per the ICMR study, “The worldwide endeavour of scientists to create a safe and effective COVID19 vaccine has resulted in the availability of 18 vaccines, which have received Emergency Use Authorization. The vaccines available against SARS-CoV-2, have shown efficacy ranging from 51 % to 94% against the original strain D614G in phase 3 clinical trials. Immune response to SARS-CoV-2 infection involves innate immune activation and antigen-specific responses of B and T cells. Particularly, the questions about the immune escape of, newly emerging VOCs in vaccinated individuals are still being explored. For example, the efficacy of AZD1222, which was reported to be 70% in the UK and Brazil, only reached 22% in South Africa.”
Althought the government has asked COVID-recovered patients to defer vaccination from 3 months, the study suggests that natural protection can be made greater by even one dose of vaccine against the Delta variant.
“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. Monitoring of breakthrough infection would make us understand the impact of new variants or VOC on the escape of vaccine-induced immunity. Data has shown again and again that if the individuals get infected post-vaccination, they have been protected from severe disease,” the study added.