11/11/2025
Emerging Infectious Disease Task Force Update: Mpox
In October 2025, Southern California health officials reported three cases of the Mpox virus caused by the Clade I strain. These individuals reported no travel history to regions known for Clade I circulation, and no direct links have been established among the three cases.
The occurrence of these three unrelated cases raises concern for local transmission of this more severe form of mpox. Clade I is endemic to Central and Eastern Africa and historically caused more severe illness and higher mortality than Clade II. Meanwhile, Clade II, the strain responsible for the large 2022-2023 global outbreak, continues to circulate in the United States at low, stable levels.
Healthcare providers should remain vigilant when screening patients for mpox based on symptoms and travel history. Persons at risk of mpox should receive the Jynneos vaccine (if not already immunized), as current guidance supports vaccination to reduce the risk of severe diseases from both clades.
To support infection preventionists, APIC has updated and reformatted its Mpox Playbook to help IPs navigate mpox preparedness, response, and communication efforts with clarity and confidence.
đź”— Access the updated APIC Mpox Playbook here: https://apic.org/monkeypox/
