Background: The purpose of this meta-analysis (PROSPERO number: CRD42021243204) is to perform extensive and penetrating analyses on the risk factors associated with reactivation or reinfection. Methods: We searched PubMed and Embase using search terms. Risk factors (including gender. length of time between first onset and recurrent diagnosis. https://www.parisnaturalfoodes.shop/product-category/nutri-nac-600-mg/