Mumbai, Nov. 12 -- In the fourth cycle of genome sequencing, Brihanmumbai Municipal Corporation (BMC) has tested 281 samples from Covid-19 positive patients in Mumbai, of which 75% (210 patients) have tested positive for the Delta variant of Sars-Cov-2, the virus that causes Covid-19, and 25% (71) have tested positive for Delta derivative of the virus.

Genome sequencing is an exercise to study the changes in the structure of the virus over time. A combination of changes in the ribonucleic acid of the virus can give birth to a new variant.

Out of 281 patients, four patients have died and all four of them had not taken any dose of the Covid-19 vaccine. They were all also over 60 years of age. None of the vaccinated patients has died.