COVID-19: Why is the Delta variant so contagious?

The delta variant of the coronavirus appears to be more contagious than its previous predecessors. Experts blame changes in the spike protein for this.

The delta variant is particularly responsible for the fourth corona wave and numerous vaccination breakthroughs. Read here what makes the mutation so contagious.

Delta variant – that’s how aggressive the mutation is

In contrast to the previous variants, the delta mutation has a shorter incubation period. This means that the time between the first contact with the virus and the onset of the disease is reduced. In addition, the viral load in the first PCR smear is usually 1,000 times higher.

American scientists* dealt with the infectivity of the Delta variant. Experiments with artificial viruses should show the cause of the high risk of infection. In contrast to other variants, the delta variant penetrates the infected cells after just one hour, with other mutations this mechanism only takes effect after several hours.

The reason for this is an accelerated merger of the spike protein with the cell membrane. The spike protein enables the virus to dock onto human cells, specifically a certain part, the ACE receptor. Changes in the structure of the protein lead to an “efficient” infection. The variation can also infect cells with few ACE receptors and thus a larger number of human cells. It is still unclear whether an increased number of cells also promotes a severe course.

However, the mutation of the spike protein is a reason for vaccine breakthroughs and a weaker effectiveness of the vaccine protection against the delta variant. Since the immune response reacts to the previous spike protein of the original variant, the vaccination could combat the mutated structures less effectively.