The novel coronavirus has been constantly mutating at faster rates than before which is delaying the vaccine production.
India had first witnessed the L strain, but now it has evolved into S and G strains.
Presently there are six different strains of the virus, a strain is a distinct genetic lineage or the ‘code’ of a virus and it is composed of amino acids. These amino acids positions are constantly found to be shifting around,which necessarily doesn’t change the viral behaviour but rather the way that our immune system responds to the same. The current vaccine studies are being carried out to target different areas of the coronavirus spike protein. This will ensure that no amount of mutations affect the vaccine’s efficacy.