The effect of pre-COVID and post-COVID vaccination on long COVID: A systematic review and meta-analysis.

Background: Long COVID affects millions of people and results in a substantial decrease in quality of life. Previous primary studies and reviews attempted to study the effect of vaccination against long COVID, but these studies varied in the cut-off time of long COVID. We adhered to the WHO's definition of long COVID and conducted a systematic review and meta-analysis on the effect of pre-COVID and post-COVID vaccination on long COVID.