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. 2026 Jan;31(3):2500958.
doi: 10.2807/1560-7917.ES.2026.31.3.2500958.

First detection and autochthonous transmission of monkeypox virus clade Ib in the Netherlands, October to November, 2025

Jelte Elsinga  1   2 , Celine van de Ven  3 , Anne de Vries  4 , Hester Coppoolse  5 , Mariska Petrignani  3 , Brigitte van Cleef  5 , Riemer van Markus  4 , Nora Carpay  6 , Catharina E van Ewijk  7 , Sjoerd Rebers  2 , Aldert Bart  8 , Karin J von Eije  9 , Brenda Westerhuis  5 , Sylvia Bruisten  5 , Leonard Schuele  9 , Marjan Boter  9 , Richard Molenkamp  9 , Bregtje Lemkes  6 , Suzanne Geerlings  6 , Henry Jc de Vries  1   10   11   12 , Marion Koopmans  9 , Marcel Jonges  2 , Bas B Oude Munnink  9 , Matthijs Ra Welkers  1   2
Affiliations

First detection and autochthonous transmission of monkeypox virus clade Ib in the Netherlands, October to November, 2025

Jelte Elsinga et al. Euro Surveill. 2026 Jan.

Abstract

In October-November 2025, eight autochthonous cases of monkeypox (MPXV) clade Ib virus infection were reported in the Netherlands. All cases were men who have sex with men aged 25-65; none required hospital admission or antiviral treatment. Phylogenetic analysis combined with contact tracing suggest multiple introductions or cryptic circulation with onwards transmission within the community. Highly related international sequences were identified dating back to August 2025, indicating sustained global community transmission of clade Ib outside the African continent.

Keywords: MPXV; Netherlands; clade Ib; epidemiology; mpox; outbreak; whole genome sequencing.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure
Figure
Phylogenetic tree containing sequences of the Dutch MPXV clade Ib infections, October–November 2025 (n = 8), within the international context of all available clade Ib sequences on Pathoplexus, 13 October 2023–10 October 2025 (n = 487)
See this image and copyright information in PMC

References

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