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Volume 32, Number 2—February 2026

Dispatch

Multiplex PCR to Differentiate Monkeypox Virus Clades

Christopher T. Williams, Alessandra Romero-Ramirez, Adeleye Adesola Semiu, Samuel Oluwafunmbi Ifabumuyi, Caitlin Greenland-Bews, Susan Gould, Dominic Wooding, Collette Allen, Anushri Somasundaran, Nicodemus Nnabuike Mkpuma, Dorcas Gado, Jolly Amoche Adole, Abdulakeem Eniola Amoo, Abisola Ajoke Adeyemi, Laure Bosquillon de Jarcy, Christine Goffinet, Jake Dunning, Malcolm G. Semple, Esto Bahizire, Afolabi Akinpelu, Thomas E. Fletcher, Ana Cubas-Atienzar, Cristina Leggio, Adeyinka Adedeji, Adesuyi A. Omoare2, Thomas Edwards2Comments to Author , and The International Severe Acute Respiratory and Emerging Infection Consortium Investigators,1
Author affiliation: Liverpool School of Tropical Medicine, Liverpool, UK (C.T. Williams, A. Romero-Ramirez, C. Greenland-Bews, S. Gould, D. Wooding, A. Somasundaran, A. Cubas-Atienzar, T. Edwards); Nigeria Centre for Disease Control and Prevention, Abuja, Nigeria (A.A. Semiu, S.O. Ifabumuyi, A. Akinpelu, A.A. Omoare); UK Health Security Agency, Porton Down–Salisbury, UK (C. Allen, C. Leggio); National Veterinary Research Institute, Vom, Nigeria (N.N. Mkpuma, D. Gado, J.A. Adole, A. Adedeji, T. Edwards); Nigeria Centre for Disease Control and Prevention Central Public Health Laboratory, Yaba, Nigeria (A.E. Amoo, A.A. Adeyemi); Charité–Universitätsmedizin Berlin, Berlin, Germany (L. Bosquillon de Jarcy); Berlin Institute of Health, Berlin (L. Bosquillon de Jarcy); Liverpool School of Tropical Medicine, Liverpool, UK (L. Bosquillon de Jarcy, C. Goffinet); University of Oxford, Oxford, UK (J. Dunning); Infectious Diseases Department, Royal Free London NHS Foundation Trust, London, UK (J. Dunning); University of Liverpool, Liverpool (M.G. Semple); Catholic University of Bukavu, Bugabo Campus, Kinshasa, Democratic Republic of the Congo (E. Bahizire); Liverpool School of Tropical Medicine, Liverpool (T.E. Fletcher)

Main Article

Table 2

Evaluation results of multiplex PCR to differentiate monkeypox virus clades from the United Kingdom and Nigeria*

Reference PCR and country Result True positive True negative False positive False negative Sensitivity, % Specificity, %
CDC assay, United Kingdom
 Total 31 13 2 1 97 (83.78–99.92) 87 (59.54–98.34)
Total Ct <35 31 13 2 0 100 (88.78–100.00) 87 (59.54–98.34)
Clade I 0 45 0 0 NA 100 (92.13–100.00)
IIa 0 45 0 0 NA 100 (92.13–100.00)
IIb 31 13 2 1 97 (83.78–99.92) 87 (59.54–98.34)
Lineage B.1
 20
 22
 0
 5
 80 (59.30–93.17)
 100 (84.56–100.00)
CDC with Sansure, United Kingdom†
 Total
 33
 13
 0
 1
 97 (84.67–99.93)
 100 (75.29–100.00)
CDC Assay, Nigeria
 Total 36 20 0 18 67 (52.53–78.91) 100 (83.16–100.00)
Total Ct <35
 32
 20
 0
 1
 97 (84.24–99.92)
 100 (83.16–100.00)
CDC assay; combined, United Kingdom and Nigeria Total 67 33 2 19 78 (67.67–86.14) 94 (80.84–99.30)
Total Ct <35 64 33 2 1 98 (91.72–99.96) 94 (80.84–99.30)

*Numbers in parentheses are 95% CIs. Ct, cycle threshold; NA, not applicable. †Discrepant samples were tested by using the Sansure Monkeypox virus Kit (Sansure-Biotech, https://www.sansureglobal.com).

Main Article

1Members of the International Severe Acute Respiratory and Emerging Infection Consortium are listed at the end of this article.

2These authors contributed equally to this article.

Page created: January 26, 2026
Page updated: February 09, 2026
Page reviewed: February 09, 2026
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