Myocarditis was only found to be slightly higher in 12-17 year olds with the moderna vaccine. The Pfizer and others did not. Presumably because Pfizer is a lower dose. But of course, this is all moot because myocarditis is usually mild and does not require hospitalization and there are myriad of other symptoms that you can get from COVID. Its not as if myocarditis is the only negative side effect of catching COVID.