April 23, 2024
Update from CDC on the current mpox outbreak in the Democratic Republic of Congo
CDC and its partners continue to respond to the global outbreak of mpox that began in May 2022. CDC is also currently monitoring increasing reports of mpox in the Democratic Republic of the Congo (DRC) since 2023. These cases involve a virus type (clade I) that can cause more infections that are severe than the virus type that has been causing the ongoing 2022 global mpox outbreak (clade II).
Both clade I and clade II mpox can lead to a large number of lesions distributed across the body and a need for inpatient clinical management. While clade II mpox is self-limited in immunocompetent persons, clade I mpox may cause severe disease in a higher proportion of patients, with case fatality rates ranging from 1.4% to over 10% for historic outbreaks. It may also spread more easily among household contacts. The current mpox cases in DRC appear to involve several separate outbreaks across the country, with suspected cases reported in 23 of DRC’s 26 provinces. While clade I mpox is endemic in DRC, many of these cases are being reported in new provinces and urban areas where mpox does not normally occur. In addition, the suspected cases and deaths include high numbers of children. Outbreaks along the eastern and western borders of the country pose a risk that cases could spread to neighboring countries.
The risk to the United States remains low, and there have never been documented cases of clade I mpox within the United States or in countries outside those in Africa where clade I is endemic. CDC is coordinating with state, tribal, local, and territorial jurisdictions, other federal agencies, and private partners to ensure that the United States is prepared if clade I mpox begins to spread globally.
Since mpox was first recognized in the 1970s, the majority of cases in DRC have been in children. Transmission often occurs through contact with wild animals that carry the virus, or through close, prolonged contact with cases in a household. Other rash-causing diseases of childhood, such as measles and chickenpox, occur in DRC, and right now only 8% of suspected mpox cases in DRC are laboratory-confirmed. Without more laboratory testing, it’s difficult to know if some suspected mpox cases may be caused by another disease. Malnutrition and other diseases may also be contributing to the high rates of severe illness being observed.
In the current outbreak in DRC, CDC is not aware of any confirmed reports of mpox spreading among children in schools. However, spread within households is possible, and is usually associated with close, prolonged contact with ill family members or shared spaces.
The potential risk of clade I mpox cases in children in the United States remains very low. There are no animal reservoirs of mpox in the United States, and other factors, such as average family size and access to healthcare, are vastly different.
Information for Healthcare Providers:
- A proportion of routine mpox testing uses an FDA-approved test (non-variola orthopoxvirus; NVO) that is not clade-specific.
- There are other tests available through some commercial and public health laboratories that can be used to rule out clade I mpox. These are multiplex designed tests that target both NVO and clade II.
- Patient care does not change based on clade.
- The same therapeutics and management tools are used and guided by clinical status (severity of illness, underlying health concerns).
- Therapeutics are available and because of similarities between clade I and clade II viruses can be used for both clades.
- Medical countermeasures like tecovirimat, brincidofovir, and vaccinia immune globulin intravenous (VIGIV) have been used during the ongoing clade II mpox outbreak in the United States.
- Tecovirimat is available for many patients through the STOMP Trial and Investigational New Drug (IND) protocol.
- JYNNEOS mpox vaccine is available and expected to be effective against both clade I and clade II mpox infections and is FDA approved for mpox prevention regardless of the clade.
- The Advisory Committee on Immunization Practices (ACIP) recommends the 2-dose JYNNEOS vaccine:
- For pre-exposure vaccination of people at risk for occupational exposure to orthopoxviruses (as an alternative to ACAM2000) (e.g., laboratory personnel working with orthopoxviruses)
- For people ages 18 years and older at risk of mpox during an mpox outbreak, regardless of clade and population affected
- For people ages 18 years and older currently at risk for mpox
- For people under 18 years of age who are at risk for mpox, as outlined in the current Emergency Use Authorization.
- The Advisory Committee on Immunization Practices (ACIP) recommends the 2-dose JYNNEOS vaccine:
- Medical countermeasures like tecovirimat, brincidofovir, and vaccinia immune globulin intravenous (VIGIV) have been used during the ongoing clade II mpox outbreak in the United States.
Actions for Healthcare Providers:
- Providers should be aware of the possibility of clade I mpox in travelers who have been in DRC.
- For patients with travel to DRC within 21 days of illness onset, CDC recommends that clinicians pursue mpox clade-specific testing starting with a consultation with state health departmentsfor testing options (e.g., molecular testing or genetic sequencing).
- Healthcare personnel who evaluate and provide care to patients with mpox should ensure they are familiar with and continue to follow existing CDC guidance on infection prevention and control for mpox.
- Encourage patients with risk factors for mpox be vaccinated with two doses of the JYNNEOS vaccine.
For more information on mpox please see: About Mpox
