The infected individual will be sick while lymphocytesWhite blood cells which attack pathogens by producing antibodies. work to produce enough antibodyA chemical produced by a lymphocyte in response to an antigen. to provide immunity.
This is known as the primary response.
During this response, the body will also make memory lymphocytes that remain in the body for years.
If the same microorganism is encountered again, memory lymphocytes produce high numbers of the correct antibody very quickly.
This prevents the person getting sick again and is known as the secondary response.