Description of mpox reinfection by whole genome sequencing.

Several possible mpox reinfections have been reported, however, the debate on whether these are confirmed reinfections remains open. A 30-year-old male living with HIV and a history of single-dose mpox vaccination, first diagnosed with mpox in September 2022, presented with genital ulcers in March 2023, testing positive for mpox virus. Real-time polymerase chain reaction revealed the presence of viral DNA with cycle threshold values of 24 and 25, respectively. Whole genome sequencing and phylogenetic approach allowed us to classify these viruses as Clade IIb lineage B.1 and Clade IIb lineage B.1.4, respectively. Twelve nucleotide differences were identified. The observed difference was higher than the estimate of mutations/genome/year described. These data confirm that mpox reinfection is possible and reinforces current vaccination campaigns.