Antibody levels in recovered COVID-19 patients decline quickly: research

[Warpy]

3. Not necessarily

Our immune systems are smarter than that and while the antibodies decline once the bug is gone, the memory of how to make them persists in one type of lymphocyte.

They found the same thing in recovered MERS patients but there has been no documented symptomatic reinfection.

Some memory lasts a lifetime, while another might be discarded after a few years, which is why we often need booster vaccines from time to time. Reinfection while the memory in the cell is an active one triggers a massive production of the specific antibody, and often we don't have a clue we're fighting an infection. Even when the bug is a different strain but closely related to the original, we will have a much milder case.