Does health anxiety and vaccine concern predict self-reported adverse events following COVID-19 vaccination?-A Danish national cohort study

Objectives: The nocebo effect refers to an expectation of sickness that leads to sickness in the expectant. Studies have found COVID-19 vaccines to be associated with the nocebo effect. However, the literature in this field is sparse yet important with the continuation of booster vaccines.

Study design: National cohort study.

Methods: This study used data from the Danish national cohort "BiCoVac", which contains self-reported information on both health anxiety and specific COVID-19 vaccine concern, as well as 19 systemic AEs following COVID-19 vaccination. Simple and multiple logistic regression was used to estimate the association between health anxiety and specific COVID-19 vaccine concern with having one or more systemic AEs following COVID-19 vaccination. Inverse probability weights were used to compensate for the initial dropout and loss to follow-up.

Results: Of the 85,080 participants in the study, 4 % reported health anxiety, 30 % reported specific COVID-19 vaccine concern, and 26 % one or more systemic AEs following vaccination. After adjusting for covariates, participants with health anxiety had higher odds of reporting one or more systemic AEs following vaccination compared to those without (OR, 1·21 CI 95 % [1·10; 1·33]). For specific COVID-19 vaccine concern, the OR was 1·51 CI 95 % [1·45; 1·58].

Conclusions: Participants with specific COVID-19 vaccine concern had higher odds of reporting one or more systemic AEs following vaccination compared with those who had no specific COVID-19 vaccine concern. There might be a potential to reduce AEs, with positive framing of AEs and information about nocebo. Reporting of AEs was also associated with health anxiety, but to a lesser degree.