How a 'double mutant' Indian Covid strain could pose a massive threat to Sydney

The Sydney couple who have mysteriously tested positive to coronavirus are infected by the 'double mutant' Indian variant of the disease. The B.1.617 strain was identified in the subcontinent in October, with two key mutations to the outer-spike protein that helps the virus bind and enter cells. The couple have the second of three subvariants known as B.1.617.2. Scientists are not yet sure if the strain is more infectious or more deadly than original Covid, but many fear it probably is.