Dissociable impacts of physical and psychological factors on side effects after COVID-19 vaccination in Japan: A within-subject repeated measures design

Physical characteristics and lifestyle habits linked with intact immune function enhanced side effects, whereas psychological characteristics linked with impaired immune function also enhanced side effects. These seemingly contradictory results could be explained at least partly by nocebo effects and suggest the need for psychological support for people with high levels of depressive symptoms or trait anxiety. Furthermore, interaction results imply that such support might be especially beneficial to those who are young and unaffected by lifestyle diseases while simultaneously showing high trait anxiety.