As respiratory droplets enter the body through inhalation or by contact, the virus goes down the throat to the lungs, and from there it goes to various organs namely, liver, kidney and bone marrow and sometimes may cause multi-organ failure, death depending on the viral load.
Blood system
The blood system consists of red cells, white cells, and platelets and they are floating in the plasma. While red cells are necessary for oxygenation, defects in red cells (low haemoglobin) can cause anaemia or hypoxia. White cells act as a defence to prevent outside attacks from organisms, and a defect here, impairs immunity. Platelets are needed to arrest bleeding, and a low platelet count can cause excessive bleeding. Finally, the plasma, which is about 55% of blood by volume. It is mostly water but also contains antibodies, clotting factors and proteins.
These cells form in the bone-marrow, which is also affected by COVID-19, causing impairment of production of the blood cells, by the following mechanisms: Directly infect blood cells and bone marrow stromal cells, and induce auto-antibodies and immune complexes to damage these cells.
This can cause changes in patients, such as thrombocytopenia (low platelet count), anaemia due to poor oxygenation in the affected lungs and lymphopenia (low lymphocyte count) due to immune deficiency.
Doctors and scientists say there is now a reason to believe that the virus attacks the oxygen-carrying capacity of the red blood cells in the body. The patient is technically drowning from lack of oxygen with the red blood cells in the body not having enough capacity to carry oxygen because of the attack from the virus. Whenever the lung parenchyma does not function, oxygen cannot reach the red blood cells, resulting in hypoxia (severely low oxygenation) and death.
As we don’t have new antivirals or any specific drugs for this disease at present, treatment, convalescent plasma transfusion, an old technique for combating infectious diseases was recommended, for COVID-19 patients who are likely to get critical and on ventilator support. It is not a blood transfusion, rather, the donated blood component is plasma, a yellowish liquid that containing antibodies but is devoid of red cells.
Age, co-morbidity
It is hard to know why and how the virus will affect any individual person. Though most people infected with the virus will present with few or mild symptoms, others may find themselves relying on ventilator to breathe or no longer breathing at all. The factors that increase a person’s chances of having severe symptoms from COVID-19 as researchers understand them now, are: Age, co-morbidities or other medical conditions including diabetes, heart disease, chronic lung disease and cancer, genes, since COVID-19 attaches itself to a particular receptor on the outside of cells called ACE2, which it uses to invade a cell.
