Objective: The objective of this review was to evaluate the evidence for the hypothesis that psychological stress
influences antibody response to immunization in humans. Methods: A critical review of the literature was
conducted. Results: The evidence supports an association between psychological stress and suppression of humoral
immune (antibody) response to immunization. This association is convincing in the case of secondary immune
response but weak for primary response. The lack of consistent evidence for a relation with primary response may
be attributed to a failure to consider the critical points when stress needs to be elevated in the course of the
production of antibody. Lower secondary antibody responses were found among patients with chronically high
levels of stress (severe enduring problems or high levels of trait negative affect). These responses were found most
consistently among older adults. Lower secondary responses were also found for those reporting acute stress or
negative affect, but only in studies of secretory immunoglobulin A antibody in which psychological and antibody
measures were linked very closely in time. Health practices did not mediate relations between stress and antibody
responses; however, there were indications that elevated cortisol levels among stressed patients could play a role.
Evidence also suggests the possible influences of dispositional stress-reactivity and low positive affect in the
inhibition of antibody production. Conclusions: The literature supports a relationship between psychological stress
and antibody responses to immunizations. The data are convincing in the case of secondary response but weak for
primary response. More attention to the kinetics of stress and antibody response and their interrelations is needed
in future research.