Symptoms include headaches, fatigue, abnormal heart rate and blood pressure Researchers say it could be due to an immune overreaction to the Covid protein Scientists are investigating a new condition believed to be caused by Covid vaccination - dubbed 'Long Vax'. Experts at Harvard and Yale are studying the debilitating suite of problems that appear hours, days or weeks after getting a shot but can persist for months. Patients with so-called Long Vax appear to suffer symptoms similar to 'Long Covid' — including headaches, intense tiredness, and abnormal heart rate and blood pressure. However, some symptoms appear unique to the...