The studies they do have are mostly financed by the companies who are now making billions on the vaccines. But even they have found that the problem from the vaccines has created much greater risk of heart problems than any of the current variants do. Some people die of heart disease without taking these failed vaccines... it is no justification for forcing people to take something with known risks that are far greater than what is currently being claimed.
This info came out before the vaccines. The Flu can do the same.