Adrian caught a virus while staying with his grandmother a few years later his mother and sister got the same virus this virus could spread through touch and direct contact however adrain did not contact the virus this time even though he was living with his mother and sister why did he not get sick

Explanation:

Innate immunity is the first line of defense against pathogens and is composed of the response of granulocytes, monocytes, macrophages, dendritic cells and natural killer. These lines of defense recognize foreign bodies in the body and fight them. In the case shown in the question above, Adrian's innate immunity identified specific antibodies to the virus and directed them against the antigen.

As a result, Adrian's adaptive immunity produced a greater amount of antibodies specific to the antigen, preventing the virus from infecting his body.

Adaptive immunity, despite being the organism's second line of defense, has great importance, since it is through it that memory cells are generated, preventing infections by the same microorganism from occurring or, if they occur, from being milder.