Because of the limited studies conducted so far, the efficacy of each vaccine against the Delta variant cannot be determined.
B.1.617, or Delta variant, has roughly 15-17 mutations. The first case was reported in October of 2020. B.1.617 contains three subtypes: B1.617.1, B.1.617.2, and B.1.617.3, with B.1.617.1 and B.1.617.3 designated as Variants of Interest and B.1.617.2 (Delta Plus) as Variant of Concern, respectively reports Press Information Bureau.
Sputnik V and its creators, Gamaleya Research Center for Epidemiology and Microbiology, claim that their vaccine is more effective than previous vaccines against the Delta form. The papers have been submitted for peer review to an international scientific journal.
The Gameleya Center was testing the efficacy of the Sputnik V vaccine against the Moscow strain, and it could also defend against the Delta variety, according to Alexander Gintsburg, the Center's director, as reported by RIA Novosti on June 15, 2021.
Reuters reports that the Russian vaccine developers said that their vaccine is 90 percent effective against the Delta variant of COVID-19. Its efficacy figure was calculated based on digital medical and vaccination records. However, the study has to be peer-reviewed.
The Alpha, Beta, Gamma, and Delta versions are all resistant to Covishield and Covaxin. Ongoing lab experiments were being conducted to determine the vaccine's effectiveness on the Delta Plus Variant, said the Health Ministry of India on June 28.
The National Institutes of Health said the results of a Phase 2 trial published in The Lancet Infectious Diseases demonstrate that Covaxin is "safe and well-tolerated" and effectively neutralizes the Alpha and Delta variants' reports the Times of India. The medical research agency said, "Results from two studies of blood serum from people who had received Covaxin suggest that the vaccine generates antibodies that effectively neutralize the B.1.1.7 (Alpha) and B.1.617 (Delta) variants of SARS-CoV-2, first identified in the United Kingdom and India respectively."
According to another study conducted by scientists, Covishield and Covaxin effectively prevent disease severity and mortality in fully vaccinated hospitalized patients against the Delta variant. Clinical outcomes in vaccinated individuals hospitalized with Delta variant were published in 'MedRxiv - The preprint server for health sciences.' The study has not been peer-reviewed.
WHO, in its "Weekly epidemiological update on COVID-19" on July 6, 2021, said data so far supports assertions that the Pfizer-BioNTech and AstraZeneca vaccines prevent severe COVID-19 caused by the Delta variant. However, it has admitted that the vaccines may provide less protection against milder, symptomatic disease caused by the Delta.
A new analysis by Public Health England, Pfizer BioNTech vaccine (96 percent) and Oxford-AstraZeneca vaccine (92 percent ) are highly effective on Delta variant after two doses.
Gamaleya Research Center for Epidemiology and Microbiology's papers must be peer-reviewed. Scientists have been attempting to determine whether the approved vaccines are equally effective against the Delta form since its discovery.
Furthermore, even though few studies have been conducted, further research is being done to investigate the efficacy of various vaccines against Delta variants. Therefore, we determine that the judgment is unverifiable.