Vertical transmission has been described with devastating outcomes in a case series from the Democratic Republic of Congo, where 4 cases of mpox were identified in pregnant women; 3 of these pregnancies resulted in fetal demise.10 The only fetus to survive was born to a mother with mild infection. In comparison, 2 of 3 mothers with moderate to severe disease experienced spontaneous abortion in the first trimester, and 1 pregnancy ended due to intrauterine demise during the eighteenth week of gestation, likely a complication of mpox. These cases suggest that more severe disease may be linked to worse fetal outcomes.10 Further epidemiologic studies will be crucial, given the potential implications.
Diagnosis
When considering a diagnosis of mpox, clinicians should inquire about recent travel, living arrangements, sexual history, and recent sick contacts.6 A complete skin examination should include the oral and genital areas, given the high prevalence of lesions in these areas. A skin biopsy is not recommended for the diagnosis of mpox, as nonspecific viral changes cannot be differentiated from other viral exanthems, but it often is useful to rule out other differential diagnoses.21 Additionally, immunohistochemistry and electron microscopy can be utilized to aid in a histologic diagnosis of mpox.
Polymerase chain reaction detection of orthopox or mpox DNA is the gold standard for diagnosis.6 Two swabs should be collected from each lesion by swabbing vigorously using sterile swabs made of a synthetic material such as polyester, nylon, or Dacron and placed into a sterile container or viral transport medium.22 Some laboratories may have different instructions for collection of samples, so clinicians are advised to check for instructions from their local laboratory. Deroofing lesions prior to swabbing is not necessary, and specimens can include lesional material or crust. Collection of specimens from 2 to 3 lesions is recommended, preferably from different body areas or lesions with varying morphologies. Anal or rectal swabs can be considered in patients presenting with anal pain or proctitis with clinical suspicion for mpox based on history.19
Infection Prevention
Interim guidance from the WHO on November 16, 2022, reiterated the goal of outbreak control primarily via public health measures, which includes targeted use of vaccines for at-risk populations or postexposure prophylactic vaccination within 4 days, but heavily relies on surveillance and containment techniques, such as contact tracing with monitoring of contacts for onset of symptoms and isolation of cases through the complete infectious period.23 Patients are considered infectious from symptom onset until all cutaneous lesions are re-epithelized and should remain in isolation, including from household contacts and domestic and wildlife animals, for the duration of illness.24,25 Individuals exposed to humans or animals with confirmed mpox should be monitored for the development of symptoms for 21 days following last known exposure, regardless of vaccination status, and should be instructed to measure their temperature twice daily.26 Pets exposed to mpox should be isolated from other animals and humans for 21 days following last known contact.24 Vaccination strategies for preexposure and postexposure prophylaxis (PEP) are discussed below in further detail. Postinfection, the WHO suggests use of condoms for all oral, vaginal, and anal sexual activity for 12 weeks after recovery.7
Patients with suspected or confirmed mpox in a hospital should be in a single private room on special droplet and contact precautions.27 No special air handling or negative pressure isolation is needed unless the patient is undergoing an aerosol-generating procedure (eg, intubation, endoscopy, bronchoscopy). When hospitalized, patients should have a dedicated bathroom, if possible, and at-home patients should be isolated from household members until contagion risk resolves; this includes the use of a separate bathroom, when possible. Health care personnel entering the room of a patient should don appropriate personal protective equipment (PPE), including a disposable gown, gloves, eye protection, and N95 respirator or equivalent. Recommendations include standard practices for cleaning, with wet cleaning methods preferred over dry methods, using a disinfectant that covers emerging viral pathogens, and avoidance of shaking linens to prevent the spread of infectious particles.27 A variety of Environmental Protection Agency–registered wipes with virucidal activity against emerging viruses, including those with active ingredients such as quaternary ammonium, hydrogen peroxide, and hypochlorous acid, should be used for disinfecting surfaces.28
Vaccination
ACAM2000 (Emergent Bio Solutions) and JYNNEOS (Bavarian Nordic)(also known as Imvamune or Imvanex) are available in the United States for the prevention of mpox infection.29 ACAM2000, a second-generation, replication-competent, live smallpox vaccine administered as a single percutaneous injection, is contraindicated in immunocompromised populations, including patients with HIV or on immunosuppressive or biologic therapy, pregnant individuals, people with a history of atopic dermatitis or other exfoliative skin diseases with impaired barrier function, and patients with a history of cardiac disease due to the risk of myocarditis and pericarditis.30
JYNNEOS is a nonreplicating live vaccine approved by the US Food and Drug Administration (FDA) for the prevention of mpox in individuals older than 18 years administered as 2 subcutaneous doses 4 weeks apart. Patients are considered fully vaccinated 2 weeks after the second dose, and JYNNEOS is available to pediatric patients with a single patient expanded access use authorization from the FDA.29,30 More recently, the FDA issued an emergency use authorization (EUA) for administration of the vaccine to patients younger than 18 years who are at high risk of infection after exposure.31 More importantly, the FDA also issued an EUA for the intradermal administration of JYNNEOS at one-fifth of the subcutaneous dose to expand the current vaccine supply. This EUA is based on research by Frey et al,32 which showed that intradermal administration, even at a lower dose, elicited similar immune responses among study participants as the higher dose administered subcutaneously.