Both vaccines Covishield and Covaxin are efficient against SARS-CoV-2 variants Alpha, Beta, Gamma, and Delta, while effectiveness tests against the Delta Plus variant are ongoing, the government said on Friday.
Addressing a press conference, ICMR Director General Balram Bhargava said that there are four variants of concern of the coronavirus disease Alpha, Beta, Gamma and Delta.
Bhargava said that the reduction of neutralisation capabilities of vaccine with different variants, which is based on global literature, shows that Covaxin does not change with the Alpha variant at all and so it is same as it is with the standard strain.
“Covishield reduces slightly with Alpha, by 2.5 times. For the Delta variant, Covaxin is effective but antibody response is slightly reduced to three-fold reduction, and for Covishield, it is two-fold reduction, while in Pfizer and Moderna it is seven-fold reduction,” he said.
“However, Covishield and Covaxin work against the variants of SARS-CoV-2- Alpha, Beta, Gamma and Delta that is well established for these two vaccines,” Bhargava said.
Talking about the Delta Plus variant, Bhargava informed that the Delta Plus variant is present now in 12 countries. There are 48 cases in India in 10 states but they are very localised, the Indian Council of Medical Research (ICMR) chief added.
“The Delta Plus variant has also been isolated and cultured at ICMR-NIV, and laboratory tests to check vaccine effect on Delta Plus variant are ongoing. We should have these results in seven-10 days as to whether the vaccine is working against the Delta Plus variant,” he said.
The Delta variant has about 15-17 mutations and was first reported in October last year, and it was responsible for more than 60 per cent of cases in Maharashtra in February. It has spread to 80 countries, Bhargava said.
The B.1.617 strain has three subtypes B.1.617.1, B.1.617.2 and B.1.617.3 — and B.1.617.2 (Delta variant) has been classified as a variant of concern and it has increased transmissibility, stronger binding to receptors of lung cells, potential reduction in monoclonal antibody response and potential post-vaccination immune escape, he said.
There are 16 countries where more than 25 percent of cases of Delta variant have been found, he said.
Bhargava said that the second wave of COVID-19 is not yet over. “We have still got 75 districts which have more than 10 percent prevalence. We have 92 districts which have between five-10 percent prevalence and 565 districts are less than five percent prevalence so in large part of India second wave is over”, he said.
“Covid appropriate behaviour and vaccination has to continue but continuous monitoring of mutations is important to track vaccine escape, increased transmissibility and disease severity. The next step is, if need be, vaccine composition can be changed as per the circulating variants of interest and variants of concern that can also be done with RNA vaccines and adenovirus-based vaccine can also be modified,” he said.