Genomic epidemiology of the 2025 mpox epidemic in Sierra Leone - Summary - MDSpire

Genomic epidemiology of the 2025 mpox epidemic in Sierra Leone

  • By

  • Allan K. O. Campbell

  • John Demby Sandi

  • Ifeanyi F. Omah

  • Martin Faye

  • Edyth Parker

  • Taylor Brock-Fisher

  • Crystal M. Gigante

  • Vidalyn Folorunso

  • Mohamed Saio Kamara

  • Anu Jegede Williams

  • Mouhamed Kane

  • Tiangay Mariama Patience Sallay Kallon

  • Julian Campbell

  • Kadiatu Salmata Sesay

  • Sia Mani

  • Choe Miller

  • Naomi Daniel Sesay

  • Francis Baimba

  • Mignane Ndiaye

  • Roberta Lansana

  • Ibrahim Umaru Fofanah

  • Simon Ruhweza

  • Zein Souma

  • Amanda Kargbo

  • Komba Koninga

  • Alie Tia

  • Jone Ngobeh

  • Foday Thoronka

  • Alusine Fofanah

  • Al Ozonoff

  • Colby Wilkason

  • Danny Park

  • Christopher Tomkins-Tinch

  • Marietou F. Paye

  • Christopher Shin

  • Ian Baudi

  • Brendan Blumenstiel

  • Patrick Varilly

  • Ivan Specht

  • Ben Fry

  • Karlie Zhao

  • Paul Cronan

  • Ellory Laning

  • Oludayo Oluwaseyi Ope-ewe

  • Ayotunde Elijah Sijuwola

  • Femi Saibu

  • Harouna Soumare

  • Ebenezer Kehinde Ogundana

  • Ruth Oluwaseun Obaado

  • Jolly Amoche Adole

  • Imonikhe Kennedy Kio

  • Folefac Agnes Njeandoh

  • Alexandra Tuttle

  • Walter O. Oguta

  • Jonathan Greene

  • Aminata Koroma

  • Joseph Kanu

  • Mamadou Aliou Barry

  • Aboubacry Gaye

  • Andy Mahine Diouf

  • Christine Hughes

  • Joshua I. Levy

  • Alhaji N’jai

  • Moussa Moise Diagne

  • Dolo Nosamiefan

  • George Ameh

  • John Klena

  • Monique A. Foster

  • Abebaw Kebede

  • Collins Tanui

  • Boubacar Diallo

  • Anise Happi

  • Sofonias Tessema

  • Abdourahmane Sow

  • Yenew Kebede

  • Isatta Wurie

  • James Squire

  • Doris Harding

  • Zikan Koroma

  • Mohamed Boie Jalloh

  • Amadou Alpha Sall

  • Kristian G. Andersen

  • Andrew Rambaut

  • Mohamed Alex Vandi

  • Ibrahima Socé Fall

  • Pardis Sabeti

  • Christian Happi

  • Foday Sahr

  • Donald S. Grant

  • May 12, 2026

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Objective:

To characterize the origin and spatiotemporal dynamics of the mpox outbreak in Sierra Leone through genomic analysis, highlighting its significance in outbreak management.

Key Findings:
  • Sierra Leone's outbreak is driven by a new lineage designated G.1, a descendant of clade IIb/sh2017 lineage A, indicating a shift in transmission dynamics.
  • The outbreak predominantly affected young adults aged 16–35 years with a near-equal sex distribution, suggesting a broader demographic impact.
  • Approximately 85% of reconstructed SNPs in the G.1 lineage were consistent with APOBEC3 editing, indicating sustained human transmission, which raises concerns for public health.
Interpretation:

The demographic profile of the outbreak suggests transmission dynamics within non-MSM sexual networks, differing from previous outbreaks primarily affecting MSM communities; this highlights the need for targeted public health strategies.

Limitations:
  • Limited availability of full-length MPXV genomic data from Sierra Leone and neighboring countries hampers comprehensive understanding.
  • Absence of early phase samples and uneven district-level sampling complicate the understanding of outbreak origins, potentially skewing results.
Conclusion:

The genomic analysis reveals significant insights into the transmission dynamics and evolution of MPXV in Sierra Leone, highlighting the urgent need for ongoing surveillance and research to mitigate future outbreaks.

Original Source(s)

Genomic epidemiology of the 2025 mpox epidemic in Sierra Leone

  • by Allan K. O. Campbell, John Demby Sandi, Ifeanyi F. Omah, Martin Faye, Edyth Parker, Taylor Brock-Fisher, Crystal M. Gigante, Vidalyn Folorunso, Mohamed Saio Kamara, Anu Jegede Williams, Mouhamed Kane, Tiangay Mariama Patience Sallay Kallon, Julian Campbell, Kadiatu Salmata Sesay, Sia Mani, Choe Miller, Naomi Daniel Sesay, Francis Baimba, Mignane Ndiaye, Roberta Lansana, Ibrahim Umaru Fofanah, Simon Ruhweza, Zein Souma, Amanda Kargbo, Komba Koninga, Alie Tia, Jone Ngobeh, Foday Thoronka, Alusine Fofanah, Al Ozonoff, Colby Wilkason, Danny Park, Christopher Tomkins-Tinch, Marietou F. Paye, Christopher Shin, Ian Baudi, Brendan Blumenstiel, Patrick Varilly, Ivan Specht, Ben Fry, Karlie Zhao, Paul Cronan, Ellory Laning, Oludayo Oluwaseyi Ope-ewe, Ayotunde Elijah Sijuwola, Femi Saibu, Harouna Soumare, Ebenezer Kehinde Ogundana, Ruth Oluwaseun Obaado, Jolly Amoche Adole, Imonikhe Kennedy Kio, Folefac Agnes Njeandoh, Alexandra Tuttle, Walter O. Oguta, Jonathan Greene, Aminata Koroma, Joseph Kanu, Mamadou Aliou Barry, Aboubacry Gaye, Andy Mahine Diouf, Christine Hughes, Joshua I. Levy, Alhaji N’jai, Moussa Moise Diagne, Dolo Nosamiefan, George Ameh, John Klena, Monique A. Foster, Abebaw Kebede, Collins Tanui, Boubacar Diallo, Anise Happi, Sofonias Tessema, Abdourahmane Sow, Yenew Kebede, Isatta Wurie, James Squire, Doris Harding, Zikan Koroma, Mohamed Boie Jalloh, Amadou Alpha Sall, Kristian G. Andersen, Andrew Rambaut, Mohamed Alex Vandi, Ibrahima Socé Fall, Pardis Sabeti, Christian Happi, Foday Sahr, Donald S. Grant

  • May 12, 2026

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