The primary immune response occurs after the first exposure to an antigen. During this initial encounter, the immune system is learning to recognize and respond to the specific pathogen. As a result, there is a lag phase, which is the time it takes for the body to produce antibodies against the antigen.
Contrary to being quicker, the primary immune response actually has a longer lag phase compared to the secondary immune response. The antibodies produced during this phase are primarily of the IgM type, not IgG. IgG antibodies are produced later and are characteristic of the secondary response.
It’s important to note that the peak levels of antibodies produced during the primary immune response are typically reached around 7 to 14 days after the exposure, rather than the 1 to 3 days suggested. The secondary immune response, however, is much quicker due to memory cells that have been created during the first exposure.