[http://rss.cnn.com/~r/rss/cnn_topstories/~3/egpkNr16opI/index.html](http://rss.cnn.com/~r/rss/cnn_topstories/~3/egpkNr16opI/index.html) >"The FDA added a warning about the risk of myocarditis and pericarditis to fact sheets for Moderna and Pfizer-BioNTech Covid-19 vaccines Friday."