The Coronavirus is transmitted through the droplet process, where droplets from surfaces or air are touched or inhaled. When a person is infected, the virus travels within the body and attacks organs such as the lungs and spleen. In the lungs, it attacks the epithelial cells, which form the lining of the lungs. Epithelial cells have ACE 2 receptors where the virus binds and begins to replicate and multiply. The virus eventually takes control of the cell, and when it is fully infected, the cell dies, releasing millions of virus molecules produced within. On being released, the virus attacks new cells, and the cycle of replication, multiplication, and apoptosis takes place again, re-infecting as many cells as possible.
Immune cells detect this activity in the lungs and react. B cells first act using cytokines to see infected areas. During this activity, these cells are also infected by the virus and instead work against each other as much as the infected cells. Due to this activity, T cells are produced to regulate the commotion. Helper T cells aid B cells by creating a neutralizing action to reduce the overreaction. Regulatory T cells prevent overreaction from containing immune responses. On the other hand, Neutrophils act on the infected epithelial cells and kill other immune cells with them. T killer cells are also produced at this stage; they release effector enzymes that act on both healthy and infected cells in the lungs (mass killing).
Consequently, the lung lining is left almost bare, as most of its epithelial cells have been destroyed. It is now prone to bacteria and other sicknesses like pneumonia. The lack of epithelial cells also exposes the alveolar to bacteria and tissue damage. At this stage, the patient may experience difficulties in breathing and other respiratory disorders. Extreme tissue damage due to a lack of a protective barrier can lead to more vital respiratory diseases, permanent lung damage, and even death.