Healthcare Providers

The Democratic Republic of the Congo (DRC) has experienced a large mpox outbreak with over 27,000 suspected cases and more than 1,300 deaths since January 1, 2023.

• On August 7, 2024, CDC reported that the DRC outbreak continues to grow and has resulted in clade I transmission to neighboring countries, including the Republic of Congo, Central African Republic, Burundi, Rwanda, and Uganda.
• On August 14, 2024, WHO determined that the upsurge of mpox in the DRC and a growing number of countries in Africa constitute a public health emergency of international concern (PHEIC).
• On August 15, 2024, the Public Health Agency of Sweden reported the first case of clade I MPXV infection outside of Africa.

CDC has determined that ongoing human-to-human transmission of clade I MPXV in Central and East Africa is an outbreak. In addition to general prevention strategies, CDC recommends a JYNNEOS 2-dose vaccine series for persons at risk for mpox via sexual exposure, regardless of sexual orientation or gender identity, during travel to a country with ongoing human-to-human transmission. Additional details are available in the CDC Health Alert distributed on September 23, 2024.  

To date, no clade I mpox cases have been reported in the U.S. CDC is urging clinicians to be on alert for new mpox cases and encourage vaccination for people at risk. If mpox is suspected, test even if the patient was previously vaccinated or had mpox.

Clinicians should document travel history in patients suspected of having mpox. The local health department should be contacted if a patient has traveled, or had contact with someone with mpox symptoms who traveled to DRC or any country sharing a border with DRC in the 21 days before symptom onset so that clade-specific testing can be performed through the state lab, the Division of Consolidated Laboratory Services (DCLS).

Vaccines are expected to be effective for both clade I and clade II MPXV infections. Studies in DRC are examining if tecovirimat may be effective for clade I MPXV in certain situations. Initial results show that tecovirimat is safe, but tecovirimat was not more effective in resolving mpox lesions than placebo. Patients who received supportive care (such as nutrition, hydration, and treatment of secondary infections) in the hospital were less likely to die than nonhospitalized patients.

Appropriate medical treatment is critical given the potential for severe illness, and contact tracing and containment strategies, including isolation, behavior modification, and vaccination, will be important to prevent spread if any U.S. clade I mpox cases occur. Clinicians should also refamiliarize themselves with mpox symptoms, specimen collection, laboratory testing procedures, and treatment options. Diagnostic samples and clinical waste can be managed as Category B infectious substances unless they contain or are contaminated with cultures of clade I MPXV.

For more information on the clinical and public health management of clade I MPXV in the U.S., visit CDC’s Public Health Strategies for Mpox webpage. 

For additional details on the DRC preparedness and response:

• CDC HAN Alert Update: Prevention Strategies for Mpox, including Vaccinating People at Risk via Sexual Exposure, for U.S. Travelers Visiting Countries with Clade I Mpox Outbreaks (September 23, 2024) 
• CDC HAN Alert Update: Mpox Caused by Human-to-Human Transmission of Monkeypox Virus in the Democratic Republic of the Congo with Spread to Neighboring Countries (August 7, 2024).
• CDC COCA Call: Mpox Update: Clinical Management and Outbreaks (Recorded 6/27/24)
• CDC MMWR: U.S. Preparedness and Response to Increasing Clade I Mpox Cases in the Democratic Republic of the Congo — United States, 2024
• The National Emerging Special Pathogens Training and Education Center’s (NETC) Situation Report: Mpox in the Democratic Republic of Congo

On February 12, 2024, CDC sent a message urging clinicians to remain diligent about taking thorough patient sexual histories and recommending vaccination to those who are eligible.  

If you are evaluating a patient suspected to have mpox, immediately report the suspected case to the local health department (LHD) using the Confidential Morbidity Report Portal (Epi-1) or telephone, even if testing is being conducted at a commercial laboratory.