Cytomegalovirus (CMV) has been implicated as a factor in immunosenescence, including poor antibody response to vaccination and higher immune activation and inflammation. Some people may be more or less vulnerable to the negative effects of CMV. The present investigation tested the effects of beta-blocker use and chronological age on the associations between CMV and immunity in adults aged 60-91 (N=98; 69% CMV seropositive) who were administered the trivalent influenza vaccine for up to 5years. Peak antibody response, corrected for baseline, and spring (persistent) antibody response, corrected for peak, were assessed, as well as beta-2 microglobulin (β2μ) and interleukin-6 (IL-6). In multi-level models with years at Level 1 and people at Level 2, CMV serostatus did not predict peak antibody response, but there was a 3-way interaction between CMV serostatus, age, and beta-blockers. Age was negatively associated with peak antibody, but only among adults who were CMV seropositive and taking beta-blockers. CMV seronegative adults who were not taking beta-blockers had the highest antibody persistence. CMV serostatus was not associated with β2μ or IL-6. Results suggest that CMV+ serostatus may negatively compromise antibody response to a greater degree than inflammatory markers in older adults. Furthermore, older adults who take beta-blockers may be more vulnerable to negative effects of age and CMV on peak antibody response, perhaps by virtue of their underlying health condition.