Lack of oxygen is one of the key coronavirus symptoms. According to Chinese researchers, SARS-CoV-2 attacks hemoglobin in red blood cells, making them unable to perform their main function - transport oxygen. Hemoglobin can do that thanks to a molecular “ring” (porphyrin) that holds an Iron ion or Fe2+ ion which binds with oxygen in the lungs and then gets transported to different parts and organs of the body.

Once inside a human host cell, the virus’s RNA also codes for a number of non-structural proteins that are created during the replication process. These proteins are not part of the virus itself but help the virus to hijack the cellular machinery to make sure it survives inside the cell.

Researches found that some of those non-structural proteins are able to remove the iron ions from the ring, which causes the red blood cells to lose their transporting abilities. That results in big stress applied to the lungs, and then the effect spreads to other organs, causing ARDS (Acute Respiratory Distress Syndrome) and subsequent organ failure.

Few proteins with those functions were identified - ORF8, ORF10, ORF1ab and ORF3a. It was also suggested that COVID-19 does not produce these proteins in the early stages of infection, but will do so after a certain threshold is reached. This fact could explain why some patients with coronavirus have elevated ferritin - a protein used by the organism to store iron. After the viral proteins push the iron ions out of the porphyrin ring, they start circulating in the blood, causing ferritin to be produced.

That also explains the efficiency of hydroxychloroquine and favipavir - drugs, whose main function is blocking the viral proteins replication.
Chloroquine, a very hydroxychloroquine's predecessor, can also block the attacks of ORF1ab, ORF3a and ORF10, and is also able to stop ORF8 from binding with the hemoglobin, while favipavir blocks the glycoproteins. The other function of favipavir is blocking the protein ORF7, the one responsible for the viral infiltration.

The study suggests, that certain medical protocols could be making things worse for patients. Many ER and ICU doctors are now questioning treatment protocols and also questioning the usage of ventilators in certain cases. Blood transfusion and hyperbaric medicine might be less harmful methods to fight the virus.

All these implications are still to be proven by further researches, but it is important to collect all the knowledge to see the full picture.