HCID status of monkeypox

Background

A high consequence infectious disease (HCID) is defined as:

• an acute infectious disease
• typically having a high case-fatality rate
• not always having effective prophylaxis or treatment
• often difficult to recognise and detect rapidly
• able to spread in the community and within healthcare settings
• requiring an enhanced individual, population and system response to ensure it is managed effectively, efficiently and safely

HCID status is conferred by the UK 4 nations public health agencies, with advisory committee input as required. It is used to determine the appropriate clinical and public health response pathways. It has no standing in law. It does not affect the classification of the pathogen in terms of hazard group, the management of waste or transport requirement.

Review for monkeypox

On 10 June 2022, the Advisory Committee on Dangerous Pathogens (ACDP) met and considered whether these criteria apply currently to monkeypox in the context of the current outbreak. ACDP noted the data provided on the UK cases, which have not been severe, and also that a vaccine is available and being deployed. The committee recommended that the strain of West African clade monkeypox currently in community transmission within the UK should no longer be classified as an HCID. No healthcare worker working in ambulatory pathway has been affected.

The committee noted that future importations of monkeypox from West Africa should still be classified as an HCID as the clinical outcomes might not necessarily be benign, and that monkeypox caused by Congo basin clade should remain an HCID.

On 14 and 15 June, the 4 nations public health agencies discussed the advice and were aligned with the view of ACDP.

Operational definitions

The proposed operational definition is therefore:

Monkeypox is not considered an HCID:

• without travel to West or Central Africa and without a link to a traveller from those regions, and/or
• when confirmed by sequencing to be within the current outbreak clade

Monkeypox is considered an HCID:

• with a travel history to West or Central Africa, a link to a traveller from those regions, or
• with a link to a case which is known to be outside the current outbreak clade
• when sequenced and known to be outside the current outbreak clade
• when it results from a new zoonotic jump in any country or setting

Implications

The implications of this change are as follows.

The NHS in all 4 nations will continue to draw on the expertise of HCID units in the assessment and management of cases requiring admission to hospital. This reflects the potential for severe disease being caused by the current outbreak clade in vulnerable groups and the need to appropriately manage admissions to hospital recognising the risk to staff and other vulnerable patients.

Most patients with mild symptoms who are able to self-isolate, will be managed on an outpatient basis with appropriate oversight via virtual ward or similar such arrangements.

There is no change to waste, transport or laboratory regulatory requirements as a result of the HCID derogation; however, the Department for Transport has recently amended transport and packaging classifications so that samples and waste from monkeypox cases are now classified as Category B (as per clinical waste). Laboratory cultures of monkeypox remain classified as Category A.

There is no automatic change to personal protective equipment (PPE). Recommendations are outlined in the 4 nations principles document and relevant national IPC guidance.

There is no automatic change to the public health response. The decisions on stringency of approach remain with the incident management team (IMT) and will be decided on the basis of the public health risk assessment.