The Defender substack reported on how the risk for myocarditis was known months before the public was alerted. Here is a graph of myocarditis or myopericarditis reports in males up to age 21 and by month of COVID shots, with the month of the public alert (May 2021) highlighted:
For shots taken in January and February, there were 7 myocarditis reports each month, but March shows an increase, and April verifies an exponential growth for that increase. Here is a table of monthly numbers:
Because males of age 21 or below only comprise approximately 5% of COVID shot recipients, then it would mean that no more than 1.56 million were jabbed by January:
This produces a reporting rate for myopericarditis of 5.77 per million doses by January 2021. And by April, approximately 12 million (5% of 239.99 million) total doses had gone out to males up to age 21:
Because 105 myopericarditis reports came in for shots taken up to April, the reporting rate would be 8.8 per million doses and the actual underlying rate could be over 10x higher (over 88 per million doses). But the typical overall rate for all serious adverse event reports combined is only about 9.6 per million.
This means that myocarditis alone had approximately as many reports as the typical sum total of all serious adverse events combined.
Reference
[31 million doses] — https://ourworldindata.org/covid-vaccinations
[online search tool for VAERS] — https://medalerts.org/vaersdb/index.php