Summary
Circulating antibodies can undergo further affinity maturation against new circulating antigen variants (1). This was shown with antibodies that were elicited against Influenza vaccines.
See also
1.
Tan Y-C, Blum LK, Kongpachith S, Ju C-H, Cai X, Lindstrom TM, et al. High-throughput sequencing of natively paired antibody chains provides evidence for original antigenic sin shaping the antibody response to influenza vaccination. Clinical Immunology. 2014;151(1):55–65. Available from: https://doi.org/10.1016/j.clim.2013.12.008