The answer to above lies in this simple truth: human immune system is very complex.
Antibodies form the first line of defense when foreign invaders like virus attacks human body. This defense wanes with time.
But there is a second line of defense known as cell based immunity. The body cells known as B cells and T cells take longer time to generate defense against invading virus. But these cells provide defense that is much broader and last much longer. This is why these cells get credit for providing protection against severe covid infection, oxygen, hospitalization and even death.
This is how vaccine helps fighting infection from COVID. It provides antibody to fight invading virus and help B cells and T cells to generate defense against serious virus impact.
But vaccine is still not a bullet proof guarantee against virus as the Israel and Qatar research on Pfizer vaccine has proven. These are small countries and their data was easily collected and was reliable. Such research is impossible in vast countries like India or United States. Coming back to the point, vaccine saves life even if immunity fades in long run. It strengthens body B cell and T cells
The broader cultural and social impact of the virus will not go away any time soon according to scientists globally. Even a crowd of 200 people allowed to gather, by governments in some states in India should be frowned upon.
Post Star needs your voice. We welcome your on-topic commentary, criticism and expertise.