Public Health Strategies for Mpox

Overview

Health departments play an enormous role in helping slow the spread of mpox.

The first case of clade I mpox has been reported in the United States. In collaboration with public health partners and other USG agencies, CDC has already increased surveillance, laboratory diagnostic, and case data reporting capacities, and provided clinician education to prepare for the possibility of clade I mpox cases occurring in the United States. This reported case demonstrates that these collaborations and systems are working as intended.

Domestic preparedness is necessary since transmission patterns for clade I mpox compared to clade II mpox are uncertain. Therefore, CDC offers recommendations for the clinical and public health management of clade I monkeypox virus (MPXV) in the United States. This guidance may be updated based on experience gained from any initial cases of clade I mpox observed in the United States or if there's evidence of ongoing domestic transmission.

Consistent with current mpox clinical guidance, clinical management of clade I mpox is based on the severity of mpox at diagnosis and the potential for complications because of certain conditions. Specifically, CDC recommends:

• Rapid clade-specific testing for any mpox patients with travel history to Central or Eastern Africa, or those who have had exposure to travelers from this region
• Isolation of people with possible clade I mpox during and following orthopoxvirus and mpox clade differentiation testing results
• Active monitoring of all high and some intermediate risk exposure contacts
• Close clinician, state/local health department, and CDC collaboration to monitor the clinical course of patients with clade I mpox where possible. This monitoring will help increase understanding of the clinical severity and transmission patterns of clade I mpox in the United States.

Mpox clinical guidance

Special population considerations

Diagnosis & case definition

Diagnosis

Laboratory diagnosis of mpox is performed by testing lesions using real-time PCR-based tests available at many large commercial laboratories and state public health labs.

• Both mpox clade specimens have the same biosafety considerations, but specimens identified as clade I MPXV are regulated as a select agent.
• The CDC-developed, FDA 510(k)-cleared, non-variola orthopoxvirus (NVO) test will detect both clades of MPXV but is unable to distinguish between them.
• Multiple laboratories in the United States currently perform clade-specific testing (via PCR and/or sequencing), with some of these laboratories using an EUA authorized multi-target PCR test, where specimens that are NVO positive and clade II negative are flagged for additional testing.
• CDC also provides clade differentiation testing on NVO-positive specimens referred from a large number of U.S. laboratories.
• In addition, several public health laboratories (PHLs) in the United States have developed or are developing and onboarding MPXV-clade-specific laboratory developed tests (LDT) that will expand this capability.
• CDC is developing an mpox triplex assay, which includes targets that are clade I- and clade II-specific, as well as an NVO target. CDC has submitted a pre-Emergency Use Authorization (EUA) package to the Food and Drug Administration (FDA) for review that, if approved, would provide this test to public health labs to be used under EUA, further expanding mpox clade differentiation capacity in the United States.

Case definition

A standardized national surveillance case definition for mpox has been in place since 2022. Mpox is a national notifiable condition, and the Council for State and Territorial Epidemiologists (CSTE) recommends that all states and territories make mpox cases reportable in their jurisdiction. CDC has posted interim case definitions for clade I mpox that should be applied when clade I outbreaks are limited to known endemic areas in Africa with no evidence of widespread transmission in other continents. To fulfill the criteria for a suspect or probable case of clade I mpox under the interim case definitions, one must be a case of probable or confirmed mpox according to the standardized national case definition for mpox, as well as fulfill interim clade I epidemiologic criteria.

Clinical management & notification

Patients with clade I mpox in the United States

CDC recommends clinicians and jurisdictions in the United States maintain a heightened index of suspicion for mpox in patients who have recently been in Central or Eastern Africa and present with signs and symptoms consistent with mpox. CDC offers interim clinical guidance for treatment of mpox.

If mpox is suspected in a patient with travel history or other epidemiologic link to the current clade I mpox outbreak, clinicians should contact their state/local public health laboratory (PHL) to determine where to obtain clade-specific testing as per CDC clinical testing guidance, noting CDC guidelines for collection and handling specimens for mpox testing.

Follow CDC's guidance for infection prevention and control of mpox in healthcare settings, which specifies recommended protective measures including PPE that apply to all types of mpox.

Public health notification

Clinicians diagnosing either clade of mpox should follow state and/or local mpox reporting requirements, and are encouraged to collaborate with their state and local health departments to submit case information as per CDC case reporting recommendations for health departments. If the patient has a potential epidemiologic link to clade I mpox, clinicians should contact the state and/or local health department where the patient resides promptly to report the possibility of a clade I mpox case. CSTE maintains 24/7 Epidemiology on call numbers for states and large cities.

CDC encourages the state health department and diagnosing clinician to contact the CDC Emergency Operations Center (EOC) at 770-488-7100 and request a clinical mpox consult after clade I mpox is diagnosed, regardless of the severity of illness. Such clinical consults are an opportunity better understand the course of the disease to inform future recommendations for clinical and public health management of clade I mpox in the United States.

Public health management

Clade I mpox in the United States

These public health management recommendations are intended to be used with the initial suspect, probable, or confirmed case of clade I mpox as per the interim clade I mpox case definition in the United States, or initial group of such cases (if closely clustered in time). They are intentionally cautious to maximize likelihood of preventing further transmission until additional evidence is collected and evaluated. They are subject to change as we understand more about clade I in the United States.

1. Isolation / activity restrictions: The patient should isolate at home or in an alternative location pending results of clinical testing for mpox if their clinical status enables outpatient management. If mpox diagnostic testing comes back negative, the infection prevention measures applicable to the diagnoses remaining under consideration need to be followed. If there is laboratory confirmation of mpox, CDC-recommended mpox activity restrictions should be followed until mpox has resolved.
   1. Health care providers managing patients with suspected mpox should review and follow CDC recommendations for infection prevention and control of mpox in healthcare settings.
   2. Health care facility discharge considerations should include assessment of the ability of the patient to carry out isolation and infection control recommendations in their home or other setting prior to discharge. If this may not be possible, consider alternative isolation locations.
2. Contact tracing: Conduct a public health interview to elicit names and contact information for all high and intermediate risk contacts going back 4 days prior to illness onset and ending with the resolution of the illness (or the time of the interview, if illness is not resolved).

Isolate the possible clade I mpox case-patient and begin contact tracing while laboratory confirmation of clade I mpox is pending. Any probable or confirmed case of mpox, regardless of clade, should be reported within 24 hours to the state/local health department.

Contacts of clade I mpox cases

Health departments are encouraged to support and assist with notifying contacts of any clade I mpox cases promptly, consistent with applicable state and local laws and policies. Exposed contacts who are symptomatic at the time of notification and have not yet been evaluated by a doctor or other qualified clinician should have a prompt in-person clinical evaluation, and clade-specific mpox diagnostic laboratory testing if indicated. While diagnostic test results are pending, symptomatic contacts should isolate as per CDC-recommended mpox activity restrictions.

At this time, eliciting and notifying contacts of those people identified as contacts of mpox cases ("contacts of contacts", or secondary contact tracing), is not expected to be useful.

Contact monitoring for mpox is based on exposure risk. Read more about the criteria for risk assessment for mpox exposures for either MPXV clade.

The recommended approach to monitoring contacts of possible clade I mpox cases pending results of clade-specific testing, and suspected, probable or confirmed clade I mpox cases is:

High-risk exposure

• Active monitoring by health department with daily phone calls, texts, or emails for 21 days. Any mpox symptoms or skin lesion requires timely in-person evaluation by a clinician, and clade-specific mpox diagnostic testing if indicated.
• Activity restriction per CDC guidance.
• Curtail travel during the monitoring period if their travel plans would not allow for isolation and access to prompt medical evaluation if symptoms develop.
• Mpox vaccine (if not already fully vaccinated with 2 doses of JYNNEOS or 1 dose of ACAM2000) may be offered as post-exposure prophylaxis if within acceptable post-exposure timeframe.

Intermediate exposure risk

• Self-monitoring for 21 days, in most cases, with the exceptions being immunocompromised patients and children, who should have active monitoring. Any exposed contact who has or develops mpox symptoms should be promptly evaluated by a qualified clinician, and clade-specific mpox diagnostic laboratory testing if indicated.
  • Activity restriction per CDC guidance.
• Curtail travel during the monitoring period if their travel plans would not allow for isolation and access to prompt medical evaluation if symptoms develop as per the guidance for exposed contacts who become symptomatic below.
• Mpox vaccine (if not already fully vaccinated with 2 doses of JYNNEOS or 1 dose of ACAM2000) may be offered as post-exposure prophylaxis if within acceptable post-exposure timeframe.

Low exposure risk

Self-monitoring per current CDC recommendations.

Considerations for pediatric patients

Clade I mpox transmission in DRC historically note that a substantial portion of mpox transmission occurs within households, and many cases are reported in children under 15 years of age. Household transmission is not anticipated to be a major driver of U.S. clade I spread. However, if pediatric cases are among the initial clade I mpox cases diagnosed in the United States, aggressive clinical management may be warranted, pending further information. Preventing transmission from pediatric cases and the monitoring of exposed pediatric contacts will have different operational challenges that should be proactively considered by state and local health departments. CDC and relevant public health will consider appropriate recommendations in the event warranted for pediatric cases.

Vaccination strategies

To be most effective, mpox vaccination should be included as part of broader prevention activities and routine sexual health care. For example:

Vaccination strategies

• Offering mpox vaccine alongside other vaccines like COVID-19 or flu vaccine
• Including mpox prevention in discussions about HIV PEP, HIV PReP, or doxy PEP with patients and clients
• Allowing individuals to self-attest their vaccine eligibility (i.e., providing mpox vaccination without requiring individuals to specify which criterion they meet)
• Discussing behavioral strategies to minimize risk when vaccine is not an option for the patient

Include mpox education and offer the vaccine during public health events and activities including:

• Community health fairs
• On site vaccination events where groups of people disproportionately impacted by mpox may get together
• Mobile testing vans
• Street outreach

Mpox vaccination strategies are likely to be most effective when designed and implemented in partnership with communities and groups that are disproportionately affected.

The Advisory Committee on Immunization Practices recommends persons at risk of exposure receive two doses of the JYNNEOS vaccine. At this time, only one in four of the approximately two million people eligible to receive the vaccine in the United States have received both doses.

Vaccination remains an important, but underutilized, tool in stopping the spread of mpox. The size of a potential mpox outbreak varies with a county's population immunity from vaccination coverage and previous mpox case rates. In counties with immunity greater than 50 percent, outbreaks are expected to be smaller. In communities with immunity less than 50 percent, more people being vaccinated against mpox can reduce the risk of an outbreak.

Mpox and health equity

CDC is committed to health equity, which means everyone has fair and just opportunity to attain their highest level of health. For mpox, this includes reliable access to safe and effective mpox vaccines and timely, clear, and accurate information. Many social, geographic, political, economic, and environmental factors create challenges to health equity and vaccination access.

Mpox case rates have been disproportionately higher among Black and Hispanic or Latino MSM and, in smaller numbers, Black and Hispanic or Latina women. Gender minorities, including transgender women and non-binary people, have also been disproportionately affected by mpox. Since October 2023, cases continue to occur primarily among cisgender men and those who identified as gay or bisexual.

At the same time, the most recent vaccine administration data show those who are disproportionately affected by mpox have lower vaccination rates.

Resources

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