Researchers have pinpointed two proteins that could serve as markers for identifying patients with long COVID. Elahi and his team discovered that the long COVID group had higher levels of immune cells called neutrophils and monocytes that cause inflammation, and fewer protective lymphocytes. In the blood of the long COVID patients, the team also found higher levels of various proteins related to systemic inflammation—especially galectin-9 and artemin. Higher levels of galectin-9 in patients are associated with increased inflammation and brain fog. In the case of artemin, higher levels are associated with widespread pain, more severe pain and cognitive impairment. They...