Question

how do vaccine works in order to prevent humans from any type of flu​

Answer 1

Answer:

Vaccines create immunity which protects us from an infection caused by a disease.

Answer 2

Answer:

To understand how vaccines work, it helps to first look at how the body fights illness. When germs, such as bacteria or viruses, invade the body, they attack and multiply. This invasion, called an infection, is what causes illness. The immune system uses several tools to fight infection. Blood contains red blood cells, for carrying oxygen to tissues and organs, and white or immune cells, for fighting infection. These white cells consist primarily of macrophages, B-lymphocytes and T-lymphocytes.Vaccines, like any medication, can cause side effects. The most common side effects are mild.