ObjectiveThe objective of this review was to evaluate the evidence for the hypothesis that psychological stress influences antibody response to immunization in humans.MethodsA critical review of the literature was conducted.ResultsThe 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.ConclusionsThe 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.