Related Materials: | CDC Health Alert Network (HAN) | California Health Alert Network (CAHAN) | Mpox landing page | Mpox Q&A | CDPH Information for Health Care Providers | CDPH Letter for CA Healthcare Providers for Severe Mpox (PDF)
Updated as of December 21, 2022:
The California Department of Public Health (CDPH) continues to work with local health departments (LHDs) and California health care providers on the ongoing mpox situation impacting the United States and other countries not usually endemic for mpox. Investigations in several countries and the U.S., including in California, suggest that person-to-person transmission through close contact fuels spread, and that clinical case presentations have not always been characteristic of classic mpox infections.
Mpox spreads between people primarily through direct contact with infectious lesions or mucosal surfaces (CDC Science Brief: Detection and Transmission). It can also be spread by respiratory secretions during prolonged face-to-face contact (CDC Mpox Response: Transmission).
Mpox can spread during intimate contact between people, including during sex, as well as activities like kissing, cuddling, or touching parts of the body with mpox lesions. At this time, it is not known definitively if mpox can spread through urine, feces, semen, or vaginal fluids (CDC Science Brief: Detection and Transmission). A patient should be considered a suspect case if they have a new characteristic rash OR if they have risk factors for mpox exposure and clinical suspicion for mpox.
Features of the typical disease course are shown below:
Symptom Monitoring or Isolation?
3 – 17 days
Monitor for symptoms
1 – 4 days
2 – 4 weeks
4 weeks or longer
* A person is contagious until after all the scabs on the skin have fallen off and a fresh layer of skin has formed. The infectious and recovery period may be longer in severe cases.
**To date, no cases of transmission have yet been definitively linked to exposure to infected persons who are not showing signs or symptoms of illness (see CDC Science Brief: Detection and Transmission). Knowledge regarding the means by which mpox virus spreads is rapidly evolving and is subject to change.
The rash associated with mpox classically involves vesicles or pustules that are deep-seated, firm or hard, and well-circumscribed. The lesions may umbilicate or become confluent and progress over time to scabs, however, presentations in this outbreak have not always been classic. Patients have experienced rashes without prodromal symptoms, rashes that are at different stages within an affected area, or rashes that do not involve the face or extremities but only the genital and/or perianal areas.
Clinicians should perform a thorough skin and mucosal (e.g., anal, vaginal, oral) examination for the characteristic vesicular or pustular rash of mpox; this allows for detection of lesions of which the patient may not have previously been aware.
Figure 1: Examples of mpox lesions, from CDC Health Alert Network 6/14/2022
Figure 2: Photo credit – General Hospital University of Malaga
More supportive of Mpox
Less supportive of Mpox
1. Did the patient have a prodrome (fevers, chills, headache, lymphadenopathy, flu-like symptoms)?
Yes: Recent cases have presented without an obvious prodrome. However, a patient with a strong epidemiologic link PLUS prodromal symptoms might increase suspicion of mpox. Notably lymphadenopathy is a distinguishing feature of mpox.
No: Recent cases have presented without an obvious prodrome. A patient with an epidemiologic link without prodromal symptoms might decrease suspicion of mpox – close monitoring should occur for development of a rash or other symptoms.
2. Did the patient develop a rash?
Yes: Most cases to date in California have developed a rash at some point in their course.
No: Some cases have developed anorectal pain, tenesmus or bleeding, but these were from non-visible perianal lesions.
3. Where is the rash?
Uncertain: Classically, mpox rashes have started in the face and extremities then spread to rest of body. In recent cases, rash has often begun in mucosal areas (e.g., genital, perianal, oral mucosa) and in some patients, the lesions have been scattered or localized to a specific body site rather than diffuse and have not involved the face or extremities.
4. What is the rash appearance?
Deep-seated and well-circumscribed lesions, often with central umbilication. Lesions progress through specific sequential stages, sometimes rapidly—macules, papules, vesicles, pustules, and scabs. Additional information can be found at CDC page.
Other presentations of rashes and rashes that do not progress. Remember, rashes in certain stages can be mistaken for other common rash etiologies, including sexually transmitted infectious (STIs) such as syphilis, herpes, etc.
5. Is the stage of rash consistent within each body part?
Uncertain: Classically, lesions on each part of the body evolved at the same stage; however, recent cases have had rashes at different stages of progression in the same part of the body.
Uncertain: Classically, lesions on each part of the body evolved are at the same stage; however, recent cases have had rashes at different stages of progression in the same part of the body.
6. Is the rash painful?
Yes: Mpox rash is sometimes very painful and is often a reason people seek treatment.
No: Rashes such as those associated with HSV can be painful however other STIs such as syphilis are not typically painful.
7. Did the patient test positive for other rash etiology?
No: Negative test for other etiologies that cause rashes that appear similar to mpox (e.g., VZV, HSV, syphilis) does not rule out mpox entirely. Coinfections with other STIs have been seen with mpox.
Yes: Positive test for other rash etiology, especially one that cause rashes that appear similar to mpox. Coinfections with STIs, particularly syphilis, have occurred in recent cases, so a positive test does not rule out mpox.
8. Was there contact with a known or suspect mpox case?
9. Did the patient recently participate in parties or gatherings involving sex, especially with multiple sex partners? Or did the patient participate in intimate contact at venues where there is sex on premises such as bathhouses or saunas?
Yes: There have been a number of cases and contacts that were associated with sex or extended physical contact in sex related events, in bathhouses/saunas, and/or with multiple sex partners.
No: No participation or contact with someone who has participated in these activities or attended these venues/events is less suggestive of mpox.
10. Is the patient part of a social group known to have high mpox incidence or risk?
Yes: The majority of cases seen in this outbreak have been in men or transgender persons who have sex with men, however anyone can get mpox.
No: No known linkage to a high-risk group or any reported high-risk social or sexual behaviors would be less suggestive of mpox.
*While some of the listed factors more strongly suggest an underlying mpox etiology, no one answer is absolute in determining whether to suspect mpox; instead, the collective responses and overall clinical picture should be considered.
The JYNNEOS vaccine is approved by the U.S. Food and Drug Administration (FDA) to prevent both mpox and smallpox. CDPH recommends that those who may be at risk for — or seek additional protection from — mpox infection, as defined within this guidance, be vaccinated against mpox. Vaccine providers can offer vaccine to any patient who MAY be at risk as there is currently adequate vaccine supply and there are no longer "eligibility" criteria. Persons who request vaccination should receive it without having to attest to specific risk factors.
Vaccination efforts should be prioritized for:
The JYNNEOS vaccine is approved as a series of two doses given 28 days apart. The JYNNEOS vaccine can be given in two methods:
The standard method is a subcutaneous injection which is a shot given beneath the skin in the upper arm. This method has been approved for people 18 years or older and is also authorized under an Emergency Use Authorization (EUA) for people under 18 years of age.
Public health jurisdictions and healthcare providers have the flexibility to offer the intradermal or subcutaneous regimen based on balancing optimal vaccine use and acceptance, feasibility of administration, and available vaccine supply. People of any age with a history of developing keloid scars, and individuals younger than 18 years of age, should receive the vaccine via the subcutaneous route. CDC recommends that people receive two JYNNEOS doses four weeks apart.
CDPH encourages healthcare providers to consider outreach efforts focused on improving vaccination rates in groups over-represented in cases. Healthcare providers should utilize all available tools and outreach messaging platforms to reach out to these populations, encourage vaccination and return for second doses, and be flexible on vaccination route to overcome barriers. The use of clear messaging and inclusive language are important factors in improving outreach and education, following vaccination rates.
The CDPH vaccine page and JYNNEOS Q&A has additional information and guidance about the vaccine. Contact your LHD for more information in ordering the vaccine.
Contact your LHD if you need information about sites where you can refer your patient. For additional information regarding tecovirimat treatment refer to CDPH's treatment guidance for providers.
Treatment Information for Healthcare Professionals | Mpox | Poxvirus | CDC
Clinical Considerations for Mpox in Children and Adolescents | Mpox | Poxvirus | CDC
CDC Testing Directory
CDC Clinician FAQs
Mpox fact sheet for sexually active persons
CDPH Mpox Communications Toolkit
HAN Archive - 00468 | Health Alert Network (HAN) (cdc.gov)
HAN Archive - 00475 | Health Alert Network (HAN) (cdc.gov)
HAN Archive - 00481 | Health Alert Network (HAN) (cdc.gov)
2022 United States Mpox Case | Mpox | Poxvirus | CDC
CDC Personal Protective Equipment Sequence (PDF)
WHO Mpox Fact Sheet