How Delta Variant Became Dominant In India & Bypassed Immunity

New Delhi: As the Delta variant (B.1.617.2) becomes dominant throughout the world, there are two patterns emerging — countries with low vaccination rates are seeing both case and fatality rates increase and those with high vaccination rates are seeing some case increase and minimal to no fatality increase, said Eric Topol, physician-scientist, author and editor in a tweet.

The Delta variant grew to become the dominant variant in India due to its improved ability to jump to new hosts, a new study suggested. The finding shows the unique set of mutations makes the virus more infective, leads to a higher viral load in people, and causes larger outbreak clusters. These findings by researchers in India have taken into account the outbreak patterns among healthcare workers in three Indian cities, lab analysis of how the variant reacts to antibodies and the way in which the virus infects human cells, particularly lungs.

The study has made several crucial findings, some of which have also been reflected in real-world data coming from the UK. It was conducted by the researchers from the Institute of Genomics and Integrative Biology (IGIB) in collaboration with Cambridge University’s Gupta Lab, News18 reported.

Some of the findings:

• The Delta variant has a good immune escape potential as shown in the lab. It also quickly replaced other variants and caused most of the breakthrough infections (infection after complete vaccination) in healthcare workers. For the people, what this means is that we have to be very cautious and behave appropriately, especially now that we are also seeing cases of Delta Plus. “We still do not know anything about its immune escape potential. The studies have just started,” Dr Rajesh Pandey, one of the authors of the paper and senior scientist at the Institute of Genomics and Integrative Biology was quoted as saying.
• The Delta variant had a replication advantage over Alpha variant in the lab and as per samples of over 100 healthcare workers from three Delhi hospitals who got breakthrough infections were sequenced, most of them were caused by the Delta variant.

• Based on COVID-19 cases and deaths reported from Mumbai, the study showed that by the end of January there was a 2 per cent increase in the transmissibility of the Delta variant.