Clinical Considerations for Mpox in Children and Adolescents in the U.S.

Overview

Children and adolescents in the United States can become infected with MPXV through contact with people or animals with mpox or with contaminated materials. This includes:

• Close, skin-to-skin contact such as might occur during cuddling, caregiving, or bed-sharing
• Transmission across the placenta in utero or contact during the birthing process
• Contact with body fluids and respiratory secretions of patients with mpox or with contaminated fomites
• And, in adolescents, sexual contact.

Historically, mpox has been documented in children and adolescents in many African countries and in periodic outbreaks linked to travel to these countries or imported animals from Africa, including a 2003 outbreak in the United States associated with pet prairie dogs.

In the clade II mpox outbreak in the U.S., cases of mpox among children and adolescents has been rare (<0.01% of all reported cases as of June 1, 2024). A 2022 report described the epidemiologic and clinical features of 83 cases of infection in children and adolescents. Among them, there were:

• 16 cases among children <5 years
• 12 cases in children 5-12 years
• 55 cases among adolescents 13-17 years

Most adolescents (89%) were male. The most common mode of exposure for children <12 years was close physical contact with an adult household member with mpox, while for adolescents the most common exposure was through male-to-male sexual contact.

Signs

Similar to infections in adults, the most common sign of mpox in children and adolescents is a rash that progresses from maculopapular lesions to vesicles, pustules, and finally scabs. Historical reports of clade I or II MPXV infections in children and adolescents describe that the rash is often accompanied by fever, chills, sweats, lymphadenopathy, sore throat, headache, or myalgias.

However, during the ongoing clade II outbreak in the United States, fever and lymphadenopathy have not always occurred. Other symptoms may include fatigue and headache. Difficulty swallowing or cough may occur when oropharyngeal lesions are present. Intraocular lesions, eyelid swelling, or eyelid crusting may occur when there are lesions near or in a patient's eye, which can occur when a patient touches these sites with their hand after touching a lesion. (See Clinical Features for key characteristics of mpox and pictures of lesions).

The rash of mpox may be confused with other rash illnesses that are commonly considered in children, including classic varicella (chickenpox) and varicella zoster (shingles); hand, foot, and mouth disease; measles; scabies; molluscum contagiosum; herpes; syphilis; allergic skin rashes; drug eruptions; and a variety of congenital infections. Co-infections with mpox are possible. When indicated based on clinical presentation, evaluation for etiologies other than mpox should be done at the time of testing for mpox, particularly when no epidemiologic link to a person with mpox has been identified.

In an MMWR report:

• Distribution of the rash in children was predominantly on the trunk and face, and none of the children <12 years of age had anogenital lesions.
• In contrast, most adolescents presented with anogenital lesions.
• More than 11% of 83 children and adolescents were hospitalized, with no patients requiring intensive care.
• 22% were treated with tecovirimat.
• All patients recovered without sequalae.
• There were 4 infants <1 year of age and no neonates <4 weeks of age.

Information about the disease course in neonates and young infants in the ongoing clade II outbreak is limited to case reports and series. These have included reports of low rates of complications, and one report of perinatal transmission. There was one severe case of adenovirus and MPXV coinfection where it is unclear which pathogen contributed more to the disease course.

Testing

The recommendations for testing for mpox are similar for children and adults. Tests should be performed on people for whom mpox is suspected based on clinical presentation and epidemiologic criteria. If testing is indicated, lesions should be vigorously swabbed and sent for testing according to the guidance on Preparation and Collection of Specimens. Unroofing, opening, or aspirating mpox lesions is not recommended due to the risk for sharps injury and related MPXV transmission.

Positive diagnostic results from testing of lesion material for Orthopoxvirus or MPXV DNA in people without epidemiologic criteria or known risk factors, or with atypical presentations, should be verified. Molecular tests (e.g., real-time PCR tests) are highly specific and sensitive; however, when epidemiologic criteria are absent or unknown and the Cycle threshold (Ct) value is high (generally ≥34), CDC recommends re-extraction and retesting of the specimen.

CDC can be consulted for complex cases, including those that appear atypical or questionable, and can perform additional viral specific- and clade-specific PCR testing and anti-orthopoxvirus serologic testing. For more information, see HAN Archive – 00471 | Health Alert Network (HAN) (cdc.gov) and Orthopoxvirus Testing Challenges for Persons in Populations at Low Risk or Without Known Epidemiologic Link to Mpox — United States, 2022 | MMWR (cdc.gov).

Patients with suspected mpox should be assessed for contact with people or animals having a rash or diagnosed with mpox. Clinicians should contact their jurisdictional health department (Jurisdictional Contacts) as soon as mpox is suspected.

Management and treatment

Management

As with adults, children and adolescents with mpox should be closely monitored throughout their illness and likely will benefit from supportive care and pain control. Decisions about treatment for children closely align with treatment plans for adults (see Interim Clinical Guidance for the Treatment of Mpox). For the pediatric population, particular attention should be paid to keeping skin lesions covered and preventing children from scratching lesions or touching their eyes after touching lesions, which may result in auto-inoculation and more severe illness. For more information about skin care for individuals with mpox lesions, please see Mpox: Treating severe lesions (aad.org). An ophthalmologist should be consulted and a careful ocular exam performed. Optimal fluid intake should be encouraged, particularly in people with extensive skin involvement who may have additional fluid losses.

While most cases of mpox resolve without treatment, treatment should be considered based on interim guidance for clinical treatment for children and adolescents who have the following clinical manifestations:

• Severe disease, including disseminated rash, a large number of lesions that are confluent, hemorrhagic or necrotic lesions, severe lymphadenopathy that can cause airway obstruction, involvement of multiple organ systems and associated comorbidities (for example, pulmonary involvement with nodular lesions, encephalitis, ocular disease, myocarditis, neurologic involvement), sepsis, or if the disease requires hospitalization.
• Involvement of anatomic areas which might result in serious sequelae that include scarring or strictures.

Treatment should also be considered for children and adolescents who may be at high risk for severe disease:

• Children under 1 year of age
• Children and adolescents experiencing severe immunodeficiency or immunocompromise
• Adolescents who are pregnant or breastfeeding
• Children and adolescents with a condition affecting skin integrity

Available evidence indicates that the clinical presentation of mpox in children during the ongoing outbreak of clade II is typically not more severe than that of adults. However, very few neonates and infants developed mpox; it is therefore unclear whether the youngest children could have more severe illness. Clinicians caring for young children, particularly those <6 months of age, should consult public health when considering therapeutics; antiviral treatment may be considered.

When considering treatment for a child or adolescent with mpox, clinicians should consult their jurisdictional health department. Jurisdictional health departments can facilitate consultation with CDC for additional guidance, as needed.

CDC offers a clinical consultation service (email poxvirus@cdc.gov), or healthcare providers may contact the CDC Emergency Operations Center [EOC] at (770) 488-7100) where CDC can provide additional guidance to clinicians with patient management questions.

Treatment

Tecovirimat

Tecovirimat is currently the first-line treatment for MPXV infection in people with severe disease or who are at risk for severe disease, including for children and adolescents.

Patients should be informed about the clinical trial for tecovirimat and encouraged to consider enrollment. For patients who are not eligible for STOMP or who decline to participate, tecovirimat can be provided under an expanded access protocol.

Oral tecovirimat dosing is most practical for children who weigh at least 13 kilograms (approximately 28 pounds), can take capsules or the contents of a capsule mixed with soft food, and are able to eat a fatty meal to ensure optimal drug absorption.

In the absence of an oral tecovirimat suspension formulation, IV tecovirimat may be considered for children weighing less than 13 kilograms based on clinical assessment of risk/benefit and if determined appropriate by the treating clinician. For information on weight-based dosing of tecovirimat, see the EA-IND protocol. The protocol includes instructions for opening capsules and mixing with food or liquid for infants and children who require less than a 200 mg dose, which differs from the FDA-approved TPOXX (tecovirimat) labeling.

Monitoring of renal function is recommended in pediatric patients < 2 years of age, given theoretical concerns that renal immaturity in young pediatric patients may result in higher exposure of hydroxypropyl-β-cyclodextrin, an ingredient in IV tecovirimat. Animal studies have shown potential for nephrotoxicity at very high exposure levels of hydroxypropyl-β-cyclodextrin. For more information, see Expanded Access IND Protocol: Use of Tecovirimat (TPOXX®) for Treatment of Human Non-Variola Orthopoxvirus Infections in Adults and Children.

Other treatments

Other treatments might be considered in addition to tecovirimat or as an alternative for children and adolescents who are ineligible or have a contraindication for oral or intravenous tecovirimat. These treatments should be reserved for unusual circumstances, such as very severe infections, disease progression or recrudescence (initial improvement followed by worsening) despite tecovirimat treatment, or when tecovirimat is unavailable. Use of these treatments should be in consultation with infectious disease specialists, pharmacists, state and local health departments, and CDC.

Vaccinia immune globulin (VIGIV), licensed by the FDA for the treatment of vaccinia virus vaccine complications, may be used for treatment of severe mpox infection, though it is unknown whether children will benefit from treatment. Vaccinia immune globulin is available from the US Strategic National Stockpile and can be requested by clinicians through an existing expanded access Investigational New Drug (EA-IND) protocol.

The use of the antiviral medications brincidofovir [ 670KB, 21 Pages] and cidofovir [ 828KB, 6 Pages] may also be considered, but these should be used with caution due to potential toxicity. Data are not available on the effectiveness of brincidofovir or cidofovir in treating mpox in people. However, they have been shown to be effective against orthopoxviruses in in vitro and animal studies. Brincidofovir may have a more favorable safety profile than cidofovir. Cidofovir and brincidofovir should not be used simultaneously. Cidofovir is commercially available. Brincidofovir is made available from the Strategic National Stockpile for treatment of mpox to clinicians who request and obtain an FDA-authorized single-patient emergency use IND (e-IND). Clinicians with mpox patients necessitating brincidofovir treatment need to submit an e-IND request to FDA by email (DDI.EIND@fda.hhs.gov) or phone 301-796-3400 or 1-855-543-3784 during normal business hours (8 am-4:30 pm ET M-F). During after hours, call the FDA Emergency Coordinator at 1-866-300-4374 or 301-796-8240 or email CDER-EIND@fda.hhs.gov and call the CDER Emergency Coordinator at 301-796-9900.

Topical trifluridine eye drops can be considered if there is involvement near or in the eye, in consultation with ophthalmology.

Post-exposure prophylaxis (PEP)

Data on PEP to prevent mpox in children are limited. The only vaccine that is authorized and recommended for use in children or adolescents for PEP is the JYNNEOS vaccine. PEP should not be withheld from children or adolescents who are otherwise eligible. Decisions about whether to offer PEP should take into account the level of risk from the patient's exposure and the individual patient's risk of severe disease. Vaccination, immune globulin, and antiviral medication can be used as mpox PEP. For most people, vaccination is preferred. For infants under 6 months of age, Vaccinia Immune Globulin Intravenous (VIGIV) should be considered in lieu of JYNNEOS vaccine.

When considering prophylactic modalities for a child or adolescent, clinicians should first consult their jurisdictional health department (Jurisdictional Contacts). Jurisdictional health departments can facilitate consultation with CDC for guidance regarding PEP modalities, when needed, and for assistance with the associated EA IND processes, if applicable.

Vaccines and other options for mpox PEP in children and adolescents are reviewed below.

Vaccines

JYNNEOS

JYNNEOS contains a non-replicating modified vaccinia Ankara-Bavarian Nordic (MVA-BN) strain. While JYNNEOS has not been studied specifically for children or adolescents, the same MVA-BN in the JYNNEOS vaccine has been used in studies against other diseases including tuberculosis, measles, and Ebola. These studies included children as young as 4 months old, and no serious safety concerns were reported. In the United Kingdom in 2018–2019, JYNNEOS was administered to a few young children, including infants, following exposures to mpox, with no known adverse events. JYNNEOS has also been administered to children in the United States during the ongoing clade II outbreak with no known serious adverse events to date.

JYNNEOS is available for use as post exposure prophylaxis (PEP) for children and adolescents under 18 years determined to be at high risk for MPXV infection under the Emergency Use Authorization (EUA) issued by the US Food and Drug Administration on August 9, 2022. In the ongoing clade II outbreak, children as young as 4 months have been vaccinated with JYNNEOS as PEP after a known exposure. However, VIGIV should be considered in lieu of JYNNEOS vaccine for infants <6 months.

JYNNEOS has also been administered to children in the United States during the ongoing clade II outbreak without any serious adverse events to date. Vaccination with JYNNEOS for children and adolescents aged <18 years should be administered via subcutaneous injection as two doses (0.5mL each) given four weeks apart, ideally with the first dose given within four days of exposure. The intradermal route of administration is not recommended for people <18 years, as there are no data with this route of administration in people <18 years. For more information, review EUA Fact Sheet for Healthcare Providers Administering JYNNEOS Vaccine.

Adolescents at risk for mpox may receive the JYNNEOS vaccine before an exposure.

Vaccinia immune globulin

Vaccinia immune globulin is approved for treatment of smallpox vaccine complications. Its effectiveness as mpox PEP is unknown. However, vaccinia immune globulin is available through an EA-IND for potential prevention of mpox. Particularly for infants under 6 months of age with high-risk exposures, vaccinia immune globulin can be offered as a PEP modality.

Antivirals as PEP

Antiviral medications, primarily tecovirimat, can be considered for mpox PEP in unusual circumstances, such as when vaccine is contraindicated due to an allergy to vaccine components. The effectiveness of antiviral medications as mpox PEP is unknown.

Infection control

Pediatric inpatient care

For children hospitalized with suspected or confirmed mpox, isolation and infection control procedures should take into consideration the child's age and caregiving needs, family and caregiver preferences, and individual patient and caregiver factors, including the patient's course of illness, the extent and location of lesions, the ability to cover lesions, and the risk to caregivers (e.g., pregnant or immunocompromised people). The presence of caregivers in the hospital provides immeasurable benefit to children.

In homes

Isolation and infection control measures can prevent the spread of mpox to others. Extra care should be taken to ensure all children avoid close contact with people who have mpox. If unavoidable, then children over 2 years of age should wear a well-fitting mask or respirator when interacting with members of the household who have mpox, and they should avoid any contact with rash lesions or sharing of bedding, towels, cups or utensils with household members with mpox. Household members with mpox should keep all their lesions covered. Children who have a household member who has mpox should be considered for PEP.

If a child or adolescent develops mpox, they should avoid contact with uninfected people and pets until the rash has resolved, the scabs have fallen off, and a fresh layer of intact skin has formed. When possible, whether in the hospital or at home, limit the number of caregivers to one person. Caregivers of children with mpox should avoid direct skin-to-skin contact with the child's rash. During interactions with caregivers, children over 2 years of age with mpox should wear well-fitting source control (e.g., a medical mask) when possible. Caregivers assisting with changing bandages or clothes covering the child's rash should wear gloves to avoid infection. Gloves should be disposed of after each use, followed by handwashing. If any clothing (whether on the caregiver or the child) comes into contact with the rash, it should be immediately laundered. Caregivers and household members of children with mpox should be considered for PEP.

Sexually active adolescents

Adolescents at risk for mpox may receive the JYNNEOS vaccine before an exposure. Additionally, PEP vaccine should be offered to sexually active adolescents who were exposed to MPXV.

Additional considerations

Breastfeeding a child who has mpox

Decisions about whether an infant or child with mpox may directly breastfeed from an uninfected caregiver should be considered on a case-by-case basis through weighing the benefits of breast milk with any uncertain risks of the child transmitting infection to the caregiver, particularly to a caregiver who is immunocompromised or at risk for severe infection. PEP with the JYNNEOS vaccine should be considered for the uninfected caregiver.

Neonates born to individuals with suspected, probable, or confirmed mpox

Early bathing is recommended for neonates born to individuals with suspected, probable, or confirmed mpox. Bathing can be performed using soap and water and should occur prior to the neonate receiving procedures, vaccines, and medications (e.g., Vitamin K).

PEP should be considered for neonates born to individuals with suspected, probable, or confirmed mpox. The specific therapeutic that is administered should be determined after consultation with public health authorities.

Caregivers or family members who do not have suspected, probable, or confirmed mpox can provide routine care to an uninfected neonate who is born to a person with mpox.

Neonates born to individuals with suspected, probable, or confirmed mpox should be closely monitored for the development of signs consistent with mpox, including fever, lymphadenopathy, rash, or any new signs or symptoms of illness, for 21 days following birth or the last close contact with a person with mpox during their infectious period. Monitoring should include at least daily temperature checks and full skin exams, which can be performed by a caregiver or healthcare provider.