Skip Navigation LinksClade-I-Mpox-Virus-with-Geographic-Spread-in-the-Democratic-Republic-of-the-Congo-Recommendations-for-California-Health-Car Clade I Mpox Virus with Geographic Spread in the Democratic Republic of the Congo: Recommendations for California Health Care Providers

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GAVIN NEWSOM
Governor

State of California—Health and Human Services Agency
California Department of Public Health


​​                                                            Health Advisory                                                            

TO: Healthcare Providers
Clade I Mpox Virus with Geographic Spread in the Democratic Republic of the Congo: Recommendations for California Health Care Providers
12/11/2023



Key Messages​​​​

  • California health care providers should be aware that Clade I mpox virus (MPXV) infections are occurring in the Democratic Republic of the Congo (DRC); this is a more severe form of mpox with higher fatality rates than Clade IIb, which is currently circulating in the US.

  • Providers should be aware of possible Clade I MPXV exposures and/or infections among travelers and close contacts (including sexual contacts) of travelers returning from the DRC.

  • If Clade I MPXV infection is suspected, physicians should report these immediately to their local health department and send lab specimens to the California Department of Public Health (CDPH) Viral and Rickettsial Disease Laboratory (VRDL) for clade-specific mpox testing. ​​


​Summary​

CDPH Sexually Transmitted Diseases (STD) Control Branch is issuing this California Health Alert Network (CAHAN) Health Advisory to notify clinicians and local health departments about the occurrence, geographic spread, and sexually associated human-to-human transmission of Clade I MPXV in the DRC.

On December 7, 2023, the Centers for Disease Control and Prevention (CDC) released a new Health Alert regarding cases of sexually acquired Clade I MPXV infections occurring in the DRC. Cases of Clade I MPXV have not been reported in the United States thus far since the emergence of the Clade IIb mpox epidemic in 2022. However, clinicians should be aware of the possibility of Clade I MPXV in travelers and close contacts (including sexual contacts) of travelers who have been in the DRC. Clinicians should notify their local health department (LHD) and CDPH at mpoxadmin@cdph.ca.gov if they have a patient with mpox-like symptoms, which may include a diffuse rash and lymphadenopathy, and recent travel or close contact, including sexual contact, to a traveler to the DRC. Clinicians should also submit lesion specimens for clade-specific testing for these patients.

Vaccines (e.g., JYNNEOS, ACAM2000) and other medical countermeasures (e.g., tecovirimat, brincidofovir, and vaccinia immune globulin intravenous) are available and expected to be effective for both Clade I and Clade II MPXV infections. However, vaccination coverage in the United States remains low, with only one in four people who are eligible to receive the vaccine having received both doses of JYNNEOS. CDPH recommends that clinicians encourage vaccination for patients who are eligible.

The CDPH VRDL offers MPXV testing that can discriminate between Clade I and Clade II. Providers are advised to work with their LHD to send appropriate specimens to the VRDL for MPXV testing. Please refer to the VRDL test page for mpox virus testing guidance at: Mpox test order. Contact information for CDPH/VRDL: (510) 307-8585 or VRDL.Submittal@cdph.ca.gov.  

Background

MPXV has two distinct genetic clades (subtypes that are genetically and clinically distinct). Clade I MPXV infections have historically been endemic in central Africa, more transmissible (generally via non-sexual routes), more severe and resulted in higher case fatality rates compared with those attributable to Clade IIb, the genetic subtype endemic to west Africa and currently circulating in the United States predominately affecting gay, bisexual, and other men who have sex with men (MSM).

Since January 1, 2023, the DRC has reported 12,569 suspected mpox cases (i.e., clinically diagnosed but not laboratory-confirmed) and 581 deaths (5% of suspected mpox cases). This is a substantial increase from the median 3,767 suspected mpox cases reported annually in the DRC during the years 2016-2021. Clade I MPXV has been confirmed among cases for which testing was conducted. A recent World Health Organization (WHO) report noted that mpox cases in 2023 have been reported in more DRC provinces than in previous years (i.e., 22 of 26 provinces). This includes cases in urban settings where mpox does not normally occur (Kinshasa and South Kivu Province). In two provinces, outbreaks of Clade I MPXV associated with sexual contact, including among MSM, have been reported for the first time in DRC. Mpox vaccination is not generally available in the DRC.

As part of surveillance for viral variants in the United States, CDC has tested a subset of positive MPXV or orthopoxvirus cases from commercial and state laboratories and performed clade-specific testing for 150 cases in 2023 (~12% of U.S. cases); no Clade I MPXV infections have been detected thus far. There are no direct commercial passenger flights from the DRC to the United States, and the current threat for Clade I MPXV in travelers remains low. However, Clade II MPXV infections continue to occur in the United States and California. CDPH encourages California clinicians to continue to be on alert for patients presenting with lesions consistent with mpox. Suspicion for Clade I MPXV should be high for people with travel to the DRC (or sexual or skin-skin contact with anyone who has traveled to the DRC) within 21 days of illness onset, and clade-specific MPXV testing should be performed on specimens from suspect mpox patients who report either recent travel to the DRC or sexual contact with anyone who has traveled there.

Most patients who have recovered from mpox (including infection with Clade II MPXV) or have been vaccinated with JYNNEOS or ACAM2000 are expected to have cross-protection to Clade I MPXV. However, clinicians are recommended to consider mpox as a possible diagnosis if a consistent clinical presentation occurs, even in people who are vaccinated or were previously diagnosed with mpox.

Recommendations

Recommendations fo​​r Clinicians and Health Departments

Di​​agnosis

Clinicians should continue to consider mpox when evaluating the cause of rashes. Mpox lesions may be small, firm and rubbery, deep-seated, and well-circumscribed, or they may be large, with diffuse, centrifugal lesion distribution. Lymphadenopathy may also be present.

During the Clade II outbreak, among people with severe immunocompromise (e.g., due to advanced HIV with CD4 <200 or solid organ transplantation), rash lesions have generally been diffusely distributed, appearing large, necrotic, and fungating (i.e., appearing or progressing like a fungal infection). Consideration of mpox should be heightened in patients who have epidemiologic characteristics supportive of mpox (including travel from mpox-endemic regions such as the DRC within 21 days of illness onset or sexual contact with anyone who has such travel history).

For anyone with symptoms who reports travel to the DRC or close contact (including sexual contact) with someone who traveled to the DRC within 21 days of illness onset, CDPH recommends that clinicians pursue MPXV clade-specific testing. Physicians should contact their LHD and CDPH for testing options (e.g., molecular testing or genetic sequencing). Clinicians should follow specimen collection guidelines (including collection of two swabs per lesion) to ensure specimen availability for testing. Unroofing or aspiration of lesions or otherwise using sharp instruments for mpox testing is not recommended due to the risk of sharps injury and MPXV exposure.

Treatment and Preve​​ntion

Medical countermeasures (e.g., tecovirimat, brincidofovir, and vaccinia immune globulin intravenous) that have been used during the ongoing Clade II MPXV outbreak in the United States are expected to be effective for Clade I MPXV infections. Public health authorities should be consulted promptly for any mpox cases for which severe manifestations might occur. Tecovirimat is available through the STOMP trial and Investigational New Drug (IND) protocol.

Vaccination with JYNNEOS or ACAM2000 or prior mpox infection should provide antibodies that will provide cross-protection to other orthopoxviruses, including Clade I MPXV. The Advisory Committee on Immunization Practices (ACIP) recommends that people ≥18 years of age with risk factors for mpox be vaccinated, before an exposure, with two doses of the JYNNEOS vaccine 28 days apart unless they were previously infected with mpox or already received two doses. There is no recommendation regarding vaccination for travelers who do not otherwise meet the eligibility criteria. Eligible patients who have only received one dose of the JYNNEOS vaccine should receive the second dose as soon as possible, regardless of the amount of time that has elapsed since the first dose.

Infection Prevention and Control

Healthcare personnel who evaluate and provide care to patients with mpox and laboratory personnel should continue to follow existing CDC guidance on infection prevention and control for mpox. These are effective in minimizing transmission.

Recommendations for Diagnostic Testing

Public health authorities are being encouraged to enhance surveillance efforts to aid detection of Clade I MPXV should it occur in the United States.

Specimens collected from patients who traveled to the DRC should be sent to CDPH's VRDL as expeditiously as possible. The VRDL offers MPXV testing that will discriminate between Clade I and Clade II. Providers are advised to work with their LHD to send appropriate specimens to the VRDL for MPXV testing. Please refer to the VRDL Test page for mpox virus testing guidance at this link: Mpox test order. Contact information for VRDL: (510) 307-8585 or VRDL.Submittal@cdph.ca.gov.

Laboratories should alert their LHD, CDPH, and CDC (poxvirus@cdc.gov) if they detect Clade I MPXV. All regulations should be followed for packaging and transporting specimens from suspect mpox patients as Category B for diagnostic testing. Please refer to the most recent CDC guidance for submitting specimens to CDC. Specimens that cannot be accepted for clinical testing under Clinical Laboratory Improvement Amendments (CLIA) will be redirected for surveillance purposes and tested, helping to provide critical data on the MPXV clade(s) circulating in the United States. Specimens tested under surveillance will not have patient reports sent back to the submitter.

Recommendations for the Public

There is no known risk for Clade I MPVX in the United States currently. CDPH continues to recommend people with risk factors for mpox be vaccinated with two doses of the JYNNEOS vaccine.  be vaccinated with two doses of the JYNNEOS vaccine.

If someone with risk factors for mpox has only received one dose, they should receive a second dose as soon as possible because two doses provide greater protection.

CDC has issued a Travel Health Notice for people traveling to the DRC. People who have traveled to the DRC – or those who have close contact, including sexual contact, with such travelers – should seek medical care at once if they develop a new, unexplained skin rash (lesions on any part of the body), with or without fever and chills, and avoid contact with others.

Resources

References

Kibungu EM, Vakaniaki EH, Kinganda-Lusamaki E, et al. Clade I-Associated Mpox Cases Associated with Sexual Contact, the Democratic Republic of the Congo. Emerg Infect Dis. Published online November 29, 2023.

McCollum AM, Shelus V, Hill A, et al. Epidemiology of Human Mpox – Worldwide, 2018-2021. MMWR Morb Mortal Wkly Rep. 2023;72(3):68-72. Published 2023 Jan 20.

Ulaeto D, Agafonov A, Burchfield J, et al. New nomenclature for mpox (monkeypox) and monkeypox virus clades. Lancet Infect Dis. 2023;23(3):273-275.

World Health Organization. Mpox (monkeypox) in the Democratic Republic of the Congo. November 23, 2023. ​​