A new study based on 4,605 participants in the Michigan COVID-19 Recovery Surveillance Study shows that the prevalence of long COVID symptoms at 30 and 90 days post-infection was 43% to 58% lower among adults who were fully vaccinated before infection.

The study appeared yesterday in the Annals of Epidemiology.

The 30- and 90-day timeframes were meant to compare two different definitions of long COVID. The US Centers for Disease Control and Prevention defines the condition as new or persistent symptoms 4 weeks after infection, while the World Health Organization definition defines it as 12 or more weeks after infection.