On February 11, weeks into the COVID-19 outbreak, the novel coronavirus was officially called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as most patients showed mild to severe respiratory illness. Doctors shared the same concept, based largely on commonly observed symptoms, that the virus targets human lungs. As a result, their treatment focus at that time was to deal primarily with respiratory symptoms, such as cough and shortness of breath, and control lung infection or pneumonia.

Today, by learning from hundreds of thousands of cases, doctors have gained much more knowledge about the novel coronavirus and they have recognized that it is not simply a respiratory virus that only attacks the lungs. Many other vital human organs, including the brain, heart and kidney, are also harmed by the coronavirus. Specifically, the real target of the virus is the blood vessels inside those organs, so all blood-vessel-rich organs will be invaded. Lungs are the first and hardest hit place as the organ is the most blood-vessel-rich one in the human body.

Recently, doctors found that many COVID-19 patients have been dying of strokes or pulmonary emboli, devastating conditions where small blood vessels in the brain and lung are blocked by clots. A research study published in the journal Lancet on May 11 revealed that the quick formation of blood clots followed by the blockage of blood vessels in the lungs, heart and brain is one of the life threatening tricks coronavirus plays in our body. Namely, COVID-19 begins as an illness of the lungs but kills as a blood vessel terminator.

The knowledge gained by doctors has been being quickly translated into direct clinical benefit in many hospitals for COVID-19 patients: giving them blood thinner medication, low or high dose based on patients disease condition, to prevent blood clots. A recent study from the U.S.suggests thatpatients admitted to the hospital and prescribed a full dose blood thinners have a better chance of survival and lower chance of needing to be put on a ventilator.

There is no doubt that more research has to be done before blood thinner-based treatment, including the use of aspirin, becomes a general practice in all hospitals. In the U.S., aspirin and other stronger clot-busting medications are being tested in severe COVID-19 patients to see if they really help to save lives.

One important thing that all COVID-19 patients need to note is that until solid evidence is collected, the decision to use higher doses of blood thinning medication outside of a clinical trial should be made by doctors, not patients themselves, and only on a case-by-case basis.