Severe relapse of SARS‐CoV‐2 infection in a kidney transplant recipient with negative nasopharyngeal SARS‐CoV‐2 RT‐PCR after rituximab

Immunocompromised patients may experience prolonged viral shedding after their initial SARS‐CoV‐2 infection, however, symptomatic relapses after remission currently remain rare. We herein describe a severe COVID‐19 relapse case of a kidney transplant recipient (KTR) following rituximab therapy, 3 months after a moderate COVID‐19 infection, despite viral clearance after recovery of the first episode. During the clinical relapse, the diagnosis was established on a broncho‐alveolar lavage specimen (BAL) by RT‐PCR. The infectivity of the BAL sample was confirmed on a cell culture assay. Whole genome sequencing confirmed the presence of an identical stain (Clade 20A). However, it had an acquired G142D mutation and a larger deletion of 3‐amino‐acids at position 143–145. These mutations located within the N‐terminal domain are suggested to play a role in viral entry. The diagnosis of a COVID‐19 relapse should be considered in the setting of unexplained persistent fever and/or respiratory symptoms in KTRs (especially for those after rituximab therapy), even in patients with previous negative naso‐pharyngeal SARS‐CoV‐2 PCR. A kidney transplant recipient who had received rituximab therapy suffers a severe relapse of COVID‐19 relapse three months after a moderate COVID‐19 infection, with confirmation of the presence of the identical strain by whole genome sequencing, albeit with several mutations in the N‐terminal domain.