17/07/2020
Let's understand why are we developing vaccine against Covid 19 and why itis required ?
The novel coronavirus enters the human body through respiratory droplets. Each virus has four major components: S (spike), M (Membrane), E (envelope) and N (nucleocapsid). Upon inhalation, the viral particles use the S protein to latch onto host cells and slowly infiltrate the upper portions of the respiratory tract. Their primary role is to bind to the ACE2 receptor, which is present on the epithelial cells, vascular epithelial cells and macrophages in the lungs. As a result, the lung loses pulmonary ACE2 function and becomes injured. This event also affects blood pressure and fluid and electrolyte balance. In severe cases, multiple organs can be affected and the person can die.
When our body encounters foreign microorganisms, it activates the immune system, which provides non-specific defences against any invading pathogen. This is usually in the form of neutrophils, macrophages and mast cells. After this step of preliminary elimination, the body mobilises the adaptive immune system, which consists of components that can initiate an immune response that it will be able to recollect in future, if the same pathogen invades the body again. This is achieved with the help of antibodies called immunoglobulins. How long these antibodies last in our bodies is what determines the period of immunity towards a particular pathogen.
A vaccine is a technology that allows the body to develop the ‘memory’ of fighting a pathogen by using a dysfunctional form of the pathogen.