One of the lingering mysteries of the pandemic is long COVID, the term used for a range of symptoms, from shortness of breath and fatigue to cognitive deficits, that persists many weeks or months after someone has been infected with SARS-CoV-2.

With research suggesting that up to 30% of people who have had COVID-19 are impacted by long COVID, governments have dedicated special clinics and major research funding for the condition.

The subject has also been divisive, with social media full of both support groups and skeptics. A recent French study showing some correlation between a person’s belief they had COVID-19 and their reporting of long COVID symptoms was used by skeptics to claim that the condition doesn’t exist (a conclusion the study doesn’t support). Another new study, however, suggests that vaccinations reduce the risk of long COVID, even among those who get jabbed after they’ve had COVID-19.