The reciprocal antagonism between AhR and melatonergic system is endorsed by AhR activation following viral invasion and the subsequent exhaustion of melatonin availability [77] as well as by the common occurrence of activated AhR and decreased pineal melatonin in comorbidities at high risk of fatal COVID-19 such as respiratory, cardiovascular, and metabolic disorders. This evidence concerns the gene AHR and Other metabolic disease.