Characterising long COVID-like COVID-19 vaccine reactions

Background: Chronic adverse reactions to COVID-19 vaccinations, which present similarly to long COVID, have thus far been poorly acknowledged, with little public awareness, and lack of clinical guidance. However, such reactions are increasingly being recognised in the academic literature

Aim: To characterise long COVID-like vaccine adverse reactions.

Methods: Cross-sectional online survey asking about symptoms, test results, diagnoses, and treatments in adults reporting with chronic symptoms starting shortly after a COVID-19 vaccine. Data were analysed for the whole sample, as well as comparing those who report chronic injury from a vector versus mRNA vaccine. Five cluster analyses were done to identify participant or symptom clusters.

Results: Participants reported good health prior to vaccination and poor health after, where they typically had a high symptom burden, with many respondents experiencing > 20 symptoms. The most commonly reported symptoms were fatigue, cognitive dysfunction, and exercise intolerance, with 11 pre-specified symptoms having a higher prevalence after a vector vaccine compared to mRNA recipients. Most test results came back normal, though commonly reported abnormalities included haematinics, D-dimer, anti-nuclear antibody, C-reactive protein, cardiac tests, and research-only tests. Six tests were more frequently reported as abnormal after a vector than mRNA vaccine, e.g. high D-dimer. Post-vaccine syndrome, dysautonomia, anxiety/mental health related, postural orthostatic tachycardia syndrome (POTS), and tachycardia were the most common diagnoses, often taking > 6 months to receive a diagnosis. Treatments targeting mast cell activation, inflammation, and POTS were most frequently reported as helpful. Cluster analyses did not yield clearly defined subgroups. Participants reported an overall poor healthcare experience.

Conclusion: Although there was high heterogeneity in clinical presentations and response to treatments, the findings are in accordance with our current understanding of long COVID and related illnesses such as myalgic encephalomyelitis. Neuroimmune dysfunction and coagulopathy seem to underlie many of these COVID-19 vaccines reactions, though biomedical research is needed to confirm this inference and offer effective treatments.