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High Consequence Infectious Diseases

The list of high-consequence infectious diseases (HCIDs) will be reviewed and updated by the UK’s four nation Public Health agencies, with advisory committee input as required, if new HCIDs emerge that are relevant to the UK. Please visit UK Health Security Agency for the latest update


Definition: 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: 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 upon by the UK 4 nation’s public health agencies, with advisory committee input as 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 influenza A H5N6 and H7N7*

Ebola virus disease (EVD)

Middle East respiratory syndrome (MERS)

Lassa fever

Mpox (monkeypox) (Clade I only)**

Lujo virus disease

Nipah virus infection

Marburg virus disease (MVD)

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 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 have been 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.