HOW COVID-19 ATTACKS

On average, a person who develops symptoms will feel ill for about seven days after their onset.

Typically, COVID-19 is a respiratory disease that is most harmful to the lungs. The virus enters the body through the nose, mouth or eyes, then invades the lungs.

SARS-CoV-2 can damage cilia, the hairlike projections on cells that move the protective mucus layer containing debris and microbes upward from the lungs to be expelled through the mouth and nose.

When the cells' lining in the respiratory tract gets infected, that lining can be breached by bacteria that cause pneumonia. In addition, that breach can alert the immune system to overreact, causing inflammatory responses that damage the lungs further.

Inflammation causes fluid buildup that impedes the movement of oxygen to the bloodstream. Troubled breathing can occur around five days after infection. Moderate to severe cases can involve pneumonia; recovery can take weeks. Hospital ventilators can provide oxygen under pressure, which helps push it through to the bloodstream.

Severe cases can advance to acute respiratory distress syndrome, or ARDS, characterized by fluid buildup in the lungs that prevents oxygen from reaching the blood.

The inflammation driving ARDS also triggers a flood of immune cells that start killing healthy tissue, leading to scar formation in the lungs that further impedes oxygen's movements to the blood.

Thus, the cause of most COVID-19 deaths is ARDS, in which the lungs become so fluid-filled, stiff and scarred that they can no longer provide oxygen to the bloodstream.

Nano test answer: about 11.6 days