First, the Delta version appears to be more efficient at penetrating cells compared to other versions because it is armed with more cracked spikes on its surface. In order for the corona virus to infect one of our cells, the spike protein (the thorn) binds to another receptor that is found on the surface of the cells in our body. Both proteins cleave or split, allowing a genetic material from the virus to enter the host cell. More insulated spikes means better access. Once in the cell, the delta strain also appears to be able to replicate more efficiently, the researchers said.

Combined with this skill, the Delta version is also better at preventing immune responses, whether it is as a result of a vaccine or a previous infection. To find out how, the team was able to extract a serum from blood samples collected from a variety of people, some vaccinated with Asterzenka or Pfizer vaccines and some infected with corona. The samples included a variety of variants, including the original strain first identified in Wuhan City, China. Because these people were infected with COVID-19 or received the vaccine, their blood serum contained several antibodies that were supposed to neutralize the virus.

The researchers found that the delta strain was 5.7 times less sensitive to sera (single of the serum) than previously infected people, and eight times less sensitive to sera from vaccinated people, compared to the alpha version. In other words, it took more antibodies from a person who was immunized than someone who already had COVID-19 to block the virus. In general, more antibodies — whether from a vaccine or a natural infection — were required to block the delta version compared to other strains.