Mpox Reinfection: A Rapid Systematic Review of Case Reports

Background: Mpox re-emerged worldwide with the multi-country outbreaks that occurred in May 2022, threatening the public health of human beings.

Methods: This rapid systematic review summarized mpox reinfection cases documented. Electronic databases (PubMed, MedRxiv, and Social Science Research Network) were searched without time limitation, using the keywords "mpox," "monkeypox," & "reinfection," "reoccur," "reoccurrence," "episode," and "relapse". All laboratory-confirmed cases of mpox reinfection published in the literature were included in this study.

Results: A total of seven publications (nine cases) from Africa, Europe, and South America were included. All mpox reinfection cases were male, with a median age of 36; 88.89% of cases had unprotected sexual behaviors with other males before each illness episode. The average onset interval between the two episodes was about 4 months. Perianal lesions and lymphadenopathy were major symptoms in both episodes, and no differences in clinical severity were reported between the two episodes. The mean duration of the two episodes was approximately 22 days and 13 days, respectively; which the mean duration of the second episode was shorter than the first infection ( = 2.17, = 0.0487). Sexually transmitted infections were commonly concurrent among most cases, accounting for 55.6% and 77.8% in the two episodes, respectively. Full vaccination against mpox was rare among reinfection cases.

Conclusion: A second infection is possible even in a short period. Reinforcing monitoring, reducing high-risk behaviors, and heightening health education regarding mpox for high-risk populations are crucial to limit mpox spread, including persons with a history of mpox infection.