Serum Institute of India’s Covishield vaccine was effective in combating moderate to severe coronavirus infection even when the cases of Delta variant had increased earlier this year, stated a study published in The Lancet Infectious Diseases journal on Monday.

The Lancet study focussed on the effectiveness of the Covishield vaccine between April and May in India, when the second wave of coronavirus had resulted in mounting deaths and stress on healthcare facilities.

According to the study, the efficacy of the vaccine in individuals who have taken two doses was found to be at 63%. During the moderate to severe phase of the disease, the vaccine efficacy was found to be at 81%.

The findings come at a time when a new coronavirus variant, Omicron, has spread across several countries in a week. The World Health Organization has classified Omicron as a “variant of concern” as the strain has the highest threat perception among other coronavirus variants because of its increased transmissibility, infectivity, or resistance to vaccines.

The health body on Tuesday said that the Omicron variant posed a very huge risk and is likely to spread globally. The variant’s mutations may enable it to escape the immune system and may allow it to be transmitted more widely.

Meanwhile, the Serum Institute of India has resumed the exports of Covishield to low-and-middle-income nations under the global vaccine-sharing programme Covax, NDTV reported.