Key details from the story linked above. Clearly they are studying the matter before making further recommendations.
Chen said that the Ministry of Health and Welfare’s Advisory Committee for Immunization Practices (ACIP) has decided to halt administration of second BNT doses to this age group for two weeks, during which time experts and Centers for Disease Control (CDC) physicians will look at the 16 cases of myocarditis among adolescents after BNT vaccination before making a final decision on whether to go ahead with the second shot.
My daughter in HS tells me many of her friends do not plan on getting the 2nd dose.
As for my son who is 9, I am against him getting any vaccine. He’s into sports. On his track team he just joined, some of the kids asked during his second practice whether he ever gets tired. He doesn’t. We did a 5k run in 29 minutes when he was 6 (almost 7). He cycles up mountains with me now. He swims 400m in the middle of various other pool exercises. I don’t want anything to take his heart health away.
As promised, the CECC has—via the Advisory Committee for Immunization Practices—examined data from Taiwan and internationally about the potential risks and benefits of vaccination for 12-17 year olds. Their conclusion is as follows:
Those aged 12-17 who have already gotten their first Pfizer-BioNTech shot and did not experience severe side effects get a second shot of the same brand.
[. . .]
The two shots should be spaced at least 12 weeks apart.
As with the first shot, consent forms will be needed to get the second shot. Since the initial roll-out was in late September, with a 12 week interval the second shots will be rolled out in mid December 2021.
More details from Focus Taiwan are here: https://focustaiwan.tw/society/202111290015
Your son sounds like a triathlon champion in the making