Developing long COVID appears to be more likely after two doses of a COVID-19 vaccine, suggesting that the spike protein may contribute to the phenomenon.

https://www.theepochtimes.com/health/study-finds-covid-vaccination-independently-associated-with-long-covid-syndrome-5551931?

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Characteristics and predictors of Long COVID among diagnosed cases of COVID-19

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9767341/