The concept of herd immunity is not hard to grasp. Like a phalanx of soldiers with shields all around you, you are protected by their shields if you don’t have one or have a defective one. In this case, the shields is immunity conferred by vaccines or by natural disease. Frankly, you’re better off with the vaccine. You don’t have the symptoms and complications like you would with the natural disease.
So check out this video that explains herd immunity with a visual and mathematical modeling tool: