Omicron’s race across the globe has amped up concerns about long COVID, which some estimates suggest affects a third of COVID-19 survivors. Long COVID symptoms can include pain, fatigue and brain fog weeks or months after the initial infection. As coronavirus infections soar worldwide, scientists are racing to pinpoint the cause of the baffling condition and find new treatments before a potential explosion of cases. Could it be an autoimmune disorder? Could microclots in the bloodstream be causing some of the symptoms? And can vaccination reduce the chances of developing long COVID?