Mpox: guidance on when to suspect a case definitionsof mpox

This document provides theguidance caseon definitionswhen forto non-highsuspect consequencempox, infectiousthe disease (HCID)caused mpox,by any clade of the diseasevirus called MPXV. Disease caused by theclade monkeypoxI virus.MPXV Furtheris informationmanaged onas thea HCIDhigh statusconsequence ofinfectious mpoxdisease is(HCID) available.in the UK.

When assessing patients for mpox, always a take a travel history. BeThere alertis toa thecurrent possibilityoutbreak of HCID mpox(clade (Clade I) in all patients with suspected mpox ifin there is a travel history to the Democratic Republic of the Congo (DRC) orand other specified countries in the African region. SeeFurther theinformation on affected countries can be found operationalhere. Be alert to the possibility of HCID casempox definition to(clade determineI) whetherin theall patientpatients maywith needsuspected tompox beif managedthey ashave havinga antravel HCID.history to the affected region.

Discuss any cases of mpox that may meetbe theHCID operational(clade caseI) definitionwith foryour arelevant HCIDlocal infection team (infectious diseases/microbiology/virology) who may advise further discussion with the imported fever service.service (IFS).

PossibleSuspected casempox

AThe possiblepossibility caseof ismpox definedshould asbe anyoneconsidered whoin fits one or more of the following criteria:scenarios:

• 1. where a febrilecase presents with a prodrome^† compatible with mpox infection, and where there is known prior contact with a confirmed or suspected case of mpox in the 21 days before symptom onset

• an

  Or

  2. illness where thea cliniciancase haspresents awith suspicionunexplained oflesions mpox,(for suchexample asvesicles, unexplainedpustules, lesions,nodules or ulcers) compatible with mpox anywhere on the body, including but not limited to:

  • genital,anywhere ano-genitalon orthe oralskin lesion(s)(face, –limbs, forextremities, example,torso)
  • oral, ulcers,genital nodulesor ano-genital lesions
  • proctitis – for example anorectal pain, bleeding

^†Febrileand prodromealso consists1 ofor fevermore ≥of 38°C,the chills,following headache, exhaustion, muscle aches (myalgia), joint pain (arthralgia), backache, and swollen lymph nodes (lymphadenopathy).apply:

Probable

• has case

Aan probableepidemiological caselink isto defineda asconfirmed anyone with an unexplained rash or lesion(s)suspected oncase any part of theirmpox bodyin (includingthe genital/perianal,21 oral),days orbefore proctitissymptom (for example anorectal pain, bleeding) and who:

onset
• has ana epidemiologicaltravel linkhistory to aspecified confirmed,countries probablewhere orthere highlymay probablebe casea risk of mpoxclade inI theexposure within 21 days beforeof symptom onset (see operational HCID case definition)

or

• identifies as a gay, bisexual or other man who has sex with men (GBMSM)

or

• has had one1 or more new sexual partners in the 21 days before symptom onset
• has none of the above risk factors, but has been discussed with local infection services (infectious diseases, microbiology, virology or sexual health as appropriate) and investigated locally for common diagnoses^$ without a cause identified
• has a relevant zoonotic link, including contact with a wild or captive mammal that is an African endemic species (this includes derived products, for example, game meat)

^†Prodrome consists of fever, chills, headache, exhaustion, muscle aches (myalgia), joint pain (arthralgia), backache, and swollen lymph nodes (lymphadenopathy).

^$Common diagnoses include, but are not limited to: chickenpox/varicella zoster virus (VZV), herpes simplex (HSV) and enterovirus.

Actions for a possiblesuspected orcase probableof mpox

For cases meeting the operational HCID case definition

TestThe managing clinician should contact their relevant local infection team (infectious diseases, microbiology, or virology). Local infection team to then to discuss with the IFS (0844 778 8990) who will review risk assessment and advise on the next steps for monkeypoxinvestigation virusand (MPXV),management.

For cases that do not meet the operational HCID case definition

Test for MPXV, the causative agent of mpox (using designated testing pathway). See also Mpox diagnostic testing guidance.

Undertake additional contemporaneous tests to rule out alternative diagnoses if clinically appropriate and if not done already.

If admission of patient is required for clinical reasons, admit to single room isolation at negative or neutral pressure at local hospital site with respiratory protective equipment (RPEIPC) andmeasures personalshould protectivebe equipmentundertaken (PPE)as (withper appropriatethe national IPC arrangements).manual.

Or,If if patient not requiring admission for clinical reasons: self-isolation at home (based on assessment by the clinician and following UKHSA guidance).guidance.

Or,If ifadmission of patient is not requiringrequired admission for clinical reasonsreasons, but self-isolation at home is not possible for social or medical reasons following clinician assessment:assessment, isolationpatient inshould singlebe roomadmitted atpending negativetest orresult, neutral pressure at local hospital site with RPEIPC andmeasures PPEundertaken pendingas testper resultthe (prioritisenational probableIPC cases).manual.

Highly probable case

A highly probable case is defined as a person with an orthopox virus PCR positive result where mpox remains the most likely diagnosis.

Confirmed case

A confirmed case is defined as a person with a laboratory-confirmed mpox infection (MPXV(MPXV PCR positive).

Actions for a confirmed or highly probable case

All confirmed or highly probable cases should be assessed for the need for admission based on either clinical or self-isolation requirements. The NHS provides guidance on management of patients with confirmed mpox.

All confirmed orand highly probable cases, or suspected cases undergoing testing should be notified to the local health protection team by the clinician.clinician; there is a statutory obligation for clinicians to make a clinical notification to the health protection team if it is believed that the diagnosis is mpox.

Further information

Additional mpox resources are available on GOV.UK, including guidance on vaccination and contact tracing.