This is what a lot of people do not understand. Antibodies are basically the front line soldiers fighting the virus, but there's no point keeping them deployed even after the war is over.
Memory cells circulate in the blood stream for much longer - sometimes decades for other pathogens - and if they identify their target antigen, will quickly trigger an immune response and produce new antibodies.
Having a high number of antibodies correlates with a strong immune response and lower rates of incidence, but that doesn't mean having a high number of antibodies is needed for that. It's really too early to say exactly how long term immune response works with this virus, as the only studies that have been completed so far are small samples sets or short time frames.
Memory cells circulate in the blood stream for much longer - sometimes decades for other pathogens - and if they identify their target antigen, will quickly trigger an immune response and produce new antibodies.
Having a high number of antibodies correlates with a strong immune response and lower rates of incidence, but that doesn't mean having a high number of antibodies is needed for that. It's really too early to say exactly how long term immune response works with this virus, as the only studies that have been completed so far are small samples sets or short time frames.