Consider CMV Serostatus When Recommending Flu Vaccine in Senior Patients

Older people who have cytomegalovirus (CMV, β-herpesvirus HHV5) seem to have less robust responses to the trivalent influenza vaccine than those who do not have CMV. Since CMV infection is very common (well over half of all Americans are CMV positive by age 40, and more than 90% are positive by age 80), this could be a potential barrier to successful influenza immunization efforts.

A study in the November 2016 issue of Brain, Behavior, and Immunity indicates that beta blockers (BB) may play a role in age-associated lower acute antibody responses one month following immunization. Unlike previously reported research, in this study, CMV infection by itself had no effect on acute antibody production in people aged 60 to 91 who were not taking BBs.

The study team also examined influenza antibody persistence in the spring following immunization. Springtime levels indicate the likelihood of protection during the next influenza season and represent late response. In spring, CMV-positivity by itself was associated with lower antibody titers regardless of BB use, but antibody persistence was more robust in the study participants who did not take BBs.

These researchers also noted that the study participants who took BBs had higher serum levels of a proinflammatory cytokine (IL-6) and an inflammatory marker (β2-microglobulin), which may help to explain the lowered influenza vaccine responses. If BBs increase IL-6 levels, it may lower responses in CMV-positive (but not negative) individuals.

This research also suggests CMV affects B cell function, especially memory function, more than it affects immune activation and inflammatory markers.

The researchers urged clinicians to take into account the reasons why patients were taking BBs, when making influenza vaccination decisions.