So Is Dexamethasone the cure for COVID ?
To say it bluntly it is an absolutely essential drug that has been used by clinicians and physicians from the start to fight against COVID. But to say it is the cure will be an unjust statement. You see dexamethasone is a steroid drug. Steroids are natural human hormones produced by the adrenal glands in response to a variety of stimuli including stress. Steroids work by being taken up by the cells and bind to the glucocorticoid receptors that are then transported to the nucleus of the cell where they interact with gluco-corticoid response elements that either guide transactivation or transrepression (transcription is a process of mRNA formation).
Another role of steroids is their anti inflammatory and immunosuppressive nature. This means that steroid help to reduce the inflammation in the body and stop inflammatory cells from going into overdrive. Inflammatory overdrive is a serious complication of inflammation and can lead to SIRS.
Steroid drugs mimic the action of steroid hormones and hence have the same functionality as them. But they are mostly used to cater to the later effect of steroid hormones i.e. to control inflammation.
With COVID-19 it is the inflammation and not the actual virus that leads to the respiratory damage. The inflammatory cells of the body are put into a hyperactive state by the virus leading to inflammation in the lung alveoli that leads to protein rich fluid leaking into the alveoli that leads to decreased oxygenation of lungs (aka hypoxia). The lungs have limited surface area for gas exchange and hence they cannot supply enough oxygen to the body which is why we sometimes have to put people on ventilators to increase the inspiratory effort and End expiratory pressures to enable maximum gas exchange.
So lets answer the question “Is Dexamethasone the cure for COVID”. Well Dexamethasone is merely a drug to combat the inflammation caused by the virus and is not a specific cure for the virus itself. In order to prevent the virus from causing the infection itself you need to rely on the COVID vaccine.
You can find more info about corticosteroid mechanism of action here.