Reports of rare and unusual blood clots have resulted in several vaccine roll outs being paused while scientists scramble to work out if the vaccines are responsible and if so how.
The unusual combination of symptoms, including a low platelet count and clots focussed in the abdomen or brain, seems similar to a rare side effect from treatment with the drug blood thinning drug Heparin - however it is not clear how the vaccines could cause the syndrome.
In this episode of Coronapod we discuss the latest theories and ask how scientists are trying to get to the bottom of this important question. Medical regulators maintain that the benefits of these vaccines significantly outweigh the risks. But as uncertainty spreads, we ponder the wider implications of these reports, including the public perception of risk.