Definition of HCID

In the UK, a high consequence infectious disease (HCID) is defined according to the following criteria:

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

Classification of HCIDs

HCIDs are further divided into contact and airborne groups:

• contact HCIDs are usually spread by direct contact with an infected patient or infected fluids, tissues and other materials, or by indirect contact with contaminated materials and fomites

• airborne HCIDs are spread by respiratory droplets or aerosol transmission, in addition to contact routes of transmission

List of high consequence infectious diseases

A list of HCIDs has been agreed by the UK 4 nations public health agencies, with advisory committee input as required:required.

)**

Contact HCIDs	Airborne HCIDs
Argentine haemorrhagic fever (Junin virus)	Andes virus infection (hantavirus)
Bolivian haemorrhagic fever (Machupo virus)	Avian influenza A H7N9 and H5N1
Crimean Congo haemorrhagic fever (CCHF)	Avian Ebola influenzavirus Adisease H5N6(EBOD) Lassa andfever Lujo H7N7*
Ebolavirus disease Marburg virus disease (EVDMVD)	Middle Severe Eastfever respiratorywith thrombocytopaenia syndrome (MERS(SFTS) Airborne HCIDs)
Lassa Andes fever	Mpoxvirus (monkeypox)infection (Clade(hantavirus) Avian Iinfluenza only)**
LujoA(H7N9) virusand disease	NipahA(H5N1) Avian virusinfluenza infection
MarburgA(H5N6) virusand diseaseA(H7N7)* Middle East respiratory syndrome (MVDMERS)	Nipah virus infection Pneumonic plague (Yersinia pestis)
Severe fever with thrombocytopaenia syndrome (SFTS)	Severe acute respiratory syndrome (SARS)***

*Human-to-human transmission has not been described to date for avian influenza A(H5N6). Human to human transmission has been described for avian influenza A(H5N1), although this was not apparent until more than 30 human cases had been reported. Both A(H5N6) and A(H5N1) often cause severe illness and fatalities. Therefore, A(H5N6) has been included in the airborne HCID list despite not meeting all of the HCID criteria.

**Based**No on the new WHO nomenclature, the mpox virus is comprised of 2 clades: Clade I (formerly Congo Basin (Central African) Clade) and Clade II (formerly West African Clade). Clade II consists of the subclades Clade IIa and Clade IIb, with the latter subclade referring mainly to the group of variants circulating in the 2022 global outbreak. See HCID status of mpox for further details on status classification.

***No cases reported since 2004, but SARS remains a notifiable disease under the International Health Regulations (2005), hence its inclusion here.

The list of HCIDs will be kept under review and updated by the UK 4 nations public health agencies, with advisory committee input as required, if new HCIDs emerge that are of relevance to the UK.

HCIDs in the UK

HCIDs are rare in the UK. When cases do occur, they tend to be sporadic and are typically associated with recent travel to an area where the infection is known to be endemic or where an outbreak is occurring. None of the HCIDs listed above are endemic in the UK, and the known animal reservoirs are not found in the UK.

AsThe of July 2022, the UK has experience of managing confirmed cases of Lassa fever, EVD,EBOD, CCHF, MERS and mpox.avian Theinfluenza vastA(H5N1). The majority of these patients acquired their infections overseas, but secondary transmission of MERS andhas mpox have occurred in the UK.

In May 2022, cases of mpox (Clade IIb, at that time classified as an HCID) without a history of travel overseas were reported in the UK. More information is available in the epidemiological overview of this outbreak.

Avian influenza A(H5N1) has caused outbreaks in wild birds and captive birds in the UKUK. in 2021 and 2022. In January 2022, the UK Health Security Agency (UKHSA) reported the first human case of avian influenza A(H5N1) in the UK. Animal-to-human transmission of avian influenza is very rare and the risk to human health is kept under frequent review. The epidemiology and genomics of A(H5N1) virus and human health risk is actively monitored by UKHSA, in collaboration with international partners.

HCID risks by country

For health professionals wishing to determine the HCID risk in any particular country, an A to Z list of countries and their respective HCID risk is available.

See HCID country risks.

Monthly summaries of global HCID events

UKHSA’s epidemic intelligence activities monitor global HCID events. These are published in a monthly summary.

Infection prevention and control in healthcare settings

Specific infection prevention and control (IPC) measures are required for suspected and confirmed HCID cases, in all healthcare settings (specialist and non-specialist).

IPC guidance appropriate for suspected and confirmed cases of Lassa fever, EVD,EBOD, CCHF, MVD, Lujo virus disease, Argentinian haemorrhagic fever, Bolivian haemorrhagic fever and SFTS, is available in the ACDP guidance.

IPC guidance for MERS, avian influenza, Nipah virus infection,infection mpox and pneumonic plague, can be found in the relevant UKHSA guidance listed below.

Links to relevant UKHSA guidance for healthcare professionals

• avian influenza

• MERS

• mpox

• Nipah virus infection

• plague

• VHF, including Ebola

• severe fever with thrombocytopaenia syndrome (SFTS)

• Andes hantavirus

Specialist advice for healthcare professionals

The Imported Fever Service (IFS) provides 24-hour, 7-days a week telephone access to expert clinical and microbiological advice. Hospital doctors across the UK can contact the IFS after discussion with the local microbiology, virology or infectious disease consultant.

Hospital management of confirmed HCID cases

Once an HCID has been confirmed by appropriate laboratory testing, cases in England should be transferred rapidly to a designated HCID Treatment Centre. Occasionally, highly probable cases may be moved to an HCID Treatment Centre before laboratory results are available.

Contact HCIDs

There are 2 principal Contact HCID Treatment Centres in England:

• the Royal Free London High Level Isolation Unit (HLIU)

• the Newcastle Royal Victoria Infirmary HLIU.

Further support for managing confirmed contact HCID cases is provided by the Royal Liverpool Hospital and the Royal Hallamshire Hospital, Sheffield.

Airborne HCIDs

There are 5 interim Airborne HCID Treatment Centres in England. Adult and paediatric services are provided by 7 NHS Trusts:England:

• Guy’s and St Thomas’ NHS Foundation Trust (adult and paediatric services)
• Royal Free London NHS Foundation Trust, with a paediatric service provided by Imperial College Healthcare NHS Foundation Trust
• Royal Liverpool and Broadgreen University Hospitals NHS Trust, with a paediatric service provided by Alder Hey Children’s NHS Foundation Trust
• Newcastle upon Tyne Hospitals NHS Foundation Trust (adult and paediatric services)
• Sheffield Teaching Hospitals NHS Foundation Trust (adult service only)

Case transfer arrangements

Hospital clinicians seeking to transfer confirmed HCID cases, or discuss the transfer of highly probable HCID cases, should contact the NHS England EPRR Duty Officer. It is expected that each case will have been discussed with the Imported Fever Service before discussing transfer.

Travel health advice for HCIDs

The National Travel Health Network and Centre (NaTHNaC) provides travel health information about a number of HCIDs, for healthcare professionals and travellers. Advice can be accessed via the Travel Health Pro website.