Continued Mpox Clade II transmission in King County and outbreak of Clade I Mpox in Central and Eastern Africa

Actions requested

• Be aware that there are two clades of mpox:
• Clade I is endemic to central Africa and is more transmissible and causes more severe disease than Clade II (mortality up to 10%). Clade I mpox cases in the Democratic Republic of the Congo (DRC) have been associated with sexual and non-sexual transmission including zoonotic exposures, household transmission, and transmission in the setting of patient care.
• Clade II was the cause of an international outbreak in 2022 that primarily affected gay, bisexual, and other MSM (GBMSM), with most cases transmitted through sex. Clade II is associated with less severe disease and a much lower mortality rate (<1%).
• Be aware that Clade II mpox cases continue to be diagnosed in King County, WA.
• Medical providers diagnosed 5 cases of mpox between early July and early August of 2024.
• All cases occurred in men who were taking HIV pre-exposure prophylaxis, four of whom reported male sex partners.
• Be aware that a large outbreak of Clade I mpox, with more than 22,000 suspected cases diagnosed in 2023, is ongoing in Central and Eastern Africa.
• This outbreak is heterogenous and includes a large number of cases in women and children under the age of 15, as well as cases in GBMSM and female sex workers and their contacts.
• On August 15, 2024, Sweden reported the first clade 1 mpox case outside of Africa.
• Vaccinate all GBMSM and all transgender persons who have sex with men with two doses of the JYNNEOS vaccine.
• Healthcare organizations should make efforts to systematically identify people who would benefit from JYNNEOS vaccine and ensure that they are offered immunization.
• This should include efforts to ensure that patients who have received one dose of vaccine receive a second dose. The second dose of vaccine should be administered 28 days or more after the first dose. There is no maximum interval between vaccine doses and there is no indication for a third dose of vaccine.
• Consider the diagnosis of mpox in all individuals with a compatible clinical presentation and epidemiologic characteristics associated with the infection.
• Epidemiologic characteristics associated with mpox include:
• Sexual or close contact to a person diagnosed with mpox or a person with a rash suggestive of mpox.
• Close or intimate in-person contact with individuals in a social or sexual network experiencing mpox activity. This includes GBMSM and transgender persons who have sex with men.
• Travel outside of the US to a country with confirmed cases of mpox or where mpox is endemic, including nations in central and eastern Africa.
• Contact with a dead or live wild animal or exotic pet that is an African endemic species or used a product derived from such animals (e.g., game meat, creams, lotions, powders, etc.).
• Symptoms of mpox may include prodromal symptoms of fever, headache, myalgia, lymphadenopathy, fatigue, chills, sore throat, nasal congestion, and a characteristic rash. The rash can affect the mouth, genitals, rectum/anus or appear elsewhere on the body and typically progresses through a series of stages before resolving. The rash usually starts as a maculopapular lesion and then progress to become vesicular and/or pustular (some with umbilication), before scabbing over and falling off.
• All or only a few of these symptoms may be present, but most cases of mpox will have a rash.
• Particularly during the 2022 outbreak and among cases occurring in the US, many patients' first manifestation of mpox is a genital or anorectal rash.
• Not all patients have a prodrome.
• Individuals with mpox are infectious starting 1-4 days prior to the onset of their first symptoms (including prodromal symptoms) until the scabs have fallen off and an intact layer of fresh skin is present for all lesions, typically 2-4 weeks.
• After infection, there can be an incubation period of roughly 1-3 weeks.
• Patients should be counseled by their provider to isolate from time of suspicion of mpox infection until negative test or complete resolution of symptoms. If patients cannot isolate completely, they should cover all lesions with clothing; avoid sharing objects (e.g., towels, drinking from the same glass); abstain from kissing, sex, and other forms of close or intimate contact; and disinfect surfaces in shared rooms between use.
• Report all cases of mpox immediately to Public Health at the time of suspicion and/or testing (206-296-4774)
• Provide appropriate recommendations around isolation to patients with a suspected case of mpox while results are pending and if they test positive.
• Medical providers should test all persons with potential mpox using a polymerase change reaction (PCR) test – ideally one that is specific to mpox. The threshold for testing should be low as the clinical presentation of mpox is highly variable.
• Mpox testing can be initiated through several commercial laboratories.
• Anticipated turnaround time for testing through commercial labs varies by laboratory and should be considered when recommending isolation to patients with suspected mpox.
• Be aware that not all commercial laboratory assays are able to distinguish between mpox virus clades. Public health will investigate all cases and attempt to have specimens sequenced to determine clade.
• Consider post-exposure prophylaxis (PEP) using the JYNNEOS vaccine for household contacts and people who have had sexual or close intimate contact with an individual with confirmed mpox virus infection.
• The JYNNEOS vaccine is now commercially available and covered by many insurance plans. Many medical providers and some community pharmacies have vaccine available.
• Consider referring patients with confirmed, probable, or a high suspicion for mpox for enrollment in a trial of the antiviral tecovirimat (TPOXX).
• Tecovirimat, an FDA-approved antiviral treatment for human smallpox disease caused by Variola virus in adults and children, may be considered for treatment in people with mpox virus infection. Its use for mpox is not approved by the FDA but is available for use under a non-research expanded access Investigational New Drug (EA-IND) protocol.
• Persons with mpox should ideally be treated as soon as possible after their onset of symptoms.
• New rules related to the TPOXX EA-IND have significantly decreased local clinicians' ability to prescribe the medication outside of a clinical trial.
• Medical providers can refer patients for evaluation for enrollment in the Study of Tecovirimat for Human Mpox Virus (STOMP) trial by calling 206-773-7129 (text or call) or 1-855-876-9997 or sending an email to uwpositiveresearch.com. Patients do not have to have or be at risk for severe mpox to enroll. Patients with mild disease may receive placebo. People with severe disease, significant active skin conditions, severe immunocompromising conditions, pregnant or lactating persons, and persons under 18 years of age will receive open-label TPOXX.