the key concern for the jcvi is the potential long—term harms from a rare side—effect from the pfizer vaccine. myocarditis is inflammation of the heart muscle, and pericarditis inflammation of the heart lining. data from the united states shows that for every one million boys fully immunised with the pfizer vaccine, there were around 60 cases of heart inflammation. among girls, it was much lower, with around eight cases per million. symptoms include chest pain, shortness of breath and palpitations. but these were generally mild symptoms and short—lived. as for covid, healthy children are at minimal risk of severe illness, with just two in a million admitted to intensive care after infection. immunising under—16s might help suppress covid but should