Three more Delhi residents have tested positive for the new Covid-19 strain as a result of door-to-door medical check-up of people who have recently arrived from the United Kingdom and those who came in their contact in the city an official said on Monday. The new Covid-19 variant is the result of multiple mutations in the spike protein of the novel coronavirus SARS-CoV-2 as well as mutations in other genomic regions of the RNA virus. Preliminary analysis suggests that it is more transmissible than previously circulating variants. With this seven residents of the national capital have so far been found infected