Consistent adverse effects reported in smallpox vaccinees have been myopericarditis and dilated cardiomyopathy; the frequency of each adverse effect exceeds what might have occurred by coincidence. 天花疫苗接种者中一致报告的不良反应包括心肌心包炎和扩张性心肌病,每种不良反应的发生频率都超过了偶发事件的水平。