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Loneliness is a psychologically aversive experience with links to well-being and health; yet its role in shaping neutralizing antibody responses, reported side effects, and affective experiences (e.g., stress, negative and positive mood) following COVID-19 vaccination remains unclear. In this preregistered study ( n = 514; 9,226 daily observations), we examined whether loneliness predicted antibody response, side effects, and negative affective reactions post-vaccination. Participants completed baseline assessments of loneliness, demographics, and health factors. After each vaccine dose, they reported daily side effects and affect for five days. Blood samples were collected one and six months after the final vaccine dose to assess SARS-CoV-2 neutralizing antibody (nAB) responses. Neither baseline nor daily mean loneliness levels were associated with the nAB response. Daily loneliness consistently predicted more adverse subjective experiences (e.g., elevated stress and negative mood, and lower positive mood) and more reported side effects following vaccination, with baseline loneliness held constant. These findings underscore how loneliness may shape post-vaccination experiences, highlighting the importance of perceived social disconnection in health-related outcomes.
Ugurlu et al. (Mon,) studied this question.