Which occurs faster, primary or secondary immune response?
Generally, the secondary immune response occurs faster.
When the body undergoes the first or primary immune response, it produces B-lymphocytes that manufacture and deploy antibodies to attack the antigen. Some of these lymphocytes become memory cells. These have a much longer lifespan and continue to exist even after the immune response has stopped.
When a secondary response occurs, these memory cells already recognize the antigen and can therefore respond much more quickly.