<i>Notes from the Field:</i> Clade II Mpox Surveillance Update — United States, October 2023–April 2024
Alexandra Tuttle, Christine M. Hughes, Mitchell Dvorak, Leah Aeschleman, Whitni Davidson, Kimberly Wilkins, Crystal M. Gigante, Panayampalli S. Satheshkumar, Agam K. Rao, Faisal S. Minhaj, Bryan Christensen, Jennifer H. McQuiston, Christina L. Hutson, Andrea M. McCollum
Abstract
Two clades of monkeypox virus (MPXV) are known to cause human illness: clade I, which is endemic in Central Africa and is currently increasing in the Democratic Republic of the Congo, and clade II, which caused a global outbreak starting in 2022.Clade IIassociated disease is considered less severe than that of clade I and is typically self-limiting; however, immunocompromised persons, especially those with advanced HIV (i.e., CD4 T lymphocyte cell count <200 cells/mm 3 ), have experienced more severe infections (1,2).Clade II MPXV continues to circulate at low levels in the United States, but no cases of clade I MPXV have been reported.National mpox case counts peaked at approximately 3,000 per week during late July-August 2022 (Figure ), then sharply declined and remain substantially lower than case counts during the peak (59 cases per week during October 1, 2023 -April 30, 2024)).This report summarizes mpox surveillance data reported to CDC during October 1, 2023-April 30, 2024.This activity was reviewed by CDC, deemed not research, and was conducted consistent with federal law and CDC policy.*