Global transmission characteristics of mpox outbreaks: a systematic review and meta-analysis

Background: Mpox is a zoonotic infectious disease caused by the mpox virus. It was first reported in humans in the Democratic Republic of the Congo in 1970. Since then, it has mainly been prevalent in Central and West Africa. Starting from 2022, the mpox epidemic has spread globally. The objective of this study was to obtain key transmission parameters of the mpox virus, providing evidence-based support for scientific prevention and control of the epidemic worldwide. Methods: We used "mpox" and "monkeypox" as the keywords to retrieve studies from PubMed, Web of Science, and Scopus databases up to February 2025. Four key transmission parameters-basic reproduction number (R0), effective reproduction number (Rt), incubation period, and serial interval were extracted. Fixed-effect or random-effect models were used to estimate the pooled parameters. Hartung-Knapp (HKSJ) confidence intervals was reported to reflect uncertainty under high heterogeneity. The protocol of this study has been registered in the PROSPERO database (CRD42022339404). Findings: The study screened 2910 articles and included 47 articles (covering 43,387 mpox patients) based on inclusion and exclusion criteria. The R0 of mpox was 2.13 (95% CI [HKSJ]: 1.63, 2.62), the Rt of mpox was 2.51 (95% CI [HKSJ]: 2.05, 2.97), the incubation period of mpox was 9.21 (95% CI [HKSJ]: 8.03, 10.39) days, and the serial interval of mpox was 12.00 (95% CI [HKSJ]: 8.01, 15.99) days. Subgroup analysis found no significant differences in incubation period, and serial interval between men who have sex with men (MSM) and the general population. However, the Rt in the general population (2.20, 95% CI [HKSJ]: 1.71, 2.70) was smaller than the Rt in the MSM (3.08, 95% CI [HKSJ]: 2.41, 3.76). Interpretation: Mpox is a threat to global public health that cannot be ignored. This study found that each person infected with the mpox virus transmitted it to two others, and the epidemic has continued to spread. Both the incubation period and the serial interval exceeded one week, which is relatively long and has increased the difficulty of prevention and control. It is recommended that in the future, early monitoring and early warning be strengthened for high-risk populations to prevent the risk of mpox transmission. Funding: This study was funded by the Youth Beijing Scholars Program (087), National Natural Science Foundation of China (72474005, 72122001), and China Primary Health Care Foundation (20250307). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the paper. No payment was received by any of the co-authors for the preparation of this article.