Guidance

Epidemic intelligence activities

Updated 2 September 2022

Epidemic intelligence activities

The UK Health Security Agency’s (UKHSA) Emerging Infections and Zoonoses (EIZ) team gathers information about outbreaks and incidents of new and emerging infectious diseases through their Epidemic Intelligence (EI) process. Timely detection of public health threats is critical to UKHSA’s and the UK government’s responses to threats that may affect the UK public, as well as raising awareness of incidents occurring globally.

The EI process is comprised of 3 distinct steps: detection, assessment and communication.

1. Detection

EI processes are undertaken each weekday by specialised scientists in the EIZ team. Signals are predominantly detected using the World Health Organization’s (WHO) Epidemic Intelligence from Open Sources (EIOS) platform. The EIOS platform collates thousands of articles daily from a broad range of publicly available sources including media, government and ministry of health websites and news aggregators.

As articles are imported into the platform, they are automatically translated and categorised into disease topic areas. The way EIOS organises the articles, which are continuously imported into the platform, enables the EIZ team to process a large amount of information each day. In addition, the EIZ team scan approximately 50 sources outside of the EIOS platform, to maximise signal detection coverage.

The aim of the EI process is to identify any new or updated information about outbreaks and incidents involving emerging infectious diseases which might pose a threat to the UK population. Epidemiological data on other outbreaks of public health significance is also gathered for situational awareness about incidents occurring globally.

Relevant events include:

• the identification of a new or emerging infectious agent
• undiagnosed morbidity or mortality events with a potentially infectious disease aetiology
• a new incident of epidemic potential either internationally or in a UK context
• identification of a new aetiological agent of a known disease or syndrome
• zoonotic or possible zoonotic outbreaks
• new or updated national or international infectious disease guidance
• bioterrorism incidents or potential deliberate release of biological agents
• scientific journal articles and pre-prints about new and/or emerging infectious diseases

The information sources included are regularly reviewed and updated in line with specific incidents being monitored. For example, local media sources may be checked for updates relating to outbreaks occurring in a specific geographical area. Where possible, official sources of information are sought to verify signals.

All relevant information is recorded in a dedicated EI database, which includes details on the date and source of the report, a description of the incident, its geographical location, and an EI confidence rating (which depends on the source of the information). Subsequent reports with any new information are also recorded.

2. Assessment

The public health significance of newly detected incidents is determined using criteria including:

• whether the event is unusual or unexpected?
• are there unexpectedly high rates of illness or death?
• is it likely to have a serious health impact?
• is there a potential for spread beyond national borders?
• is there a potential for interference with international travel or trade?
• is there local or national capacity to contain the outbreak?
• is the incident suspected to be due to deliberate release?

Incidents which do not meet one (or more) of the above criteria may still be monitored for situational awareness.

Reports of undiagnosed morbidity or mortality events are also identified during EI activities. Due to delays in confirmatory laboratory diagnostics, disease outbreaks may initially be reported as undiagnosed morbidity and mortality events where an infectious agent is suspected but the aetiology is unknown at the time of the initial report.

Previous outbreaks of major public health significance (including COVID-19, Ebola virus disease in West Africa, and Zika virus in the Americas) have been reported in the early stages as undiagnosed morbidity or mortality events. This highlights the importance of monitoring and detecting early reports of disease outbreaks. Reports of such events are logged, assessed, and closely monitored. Events that may be of greater concern are escalated appropriately within UKHSA and to UK government.

2.1 Risk assessments

The EIZ team produce assessments to determine the risk an outbreak of a disease poses to the UK public, UK interests overseas, and other populations. Risk assessments are disseminated within UKHSA, across UK government, and to the UK devolved administrations.

Probability and impact assessments, in addition to expert opinion, are used to inform the risk assessments. The probability of introduction of a pathogen into the UK population depends on the availability of routes of introduction into the UK, the likelihood of exposure, population susceptibility, and transmission mechanisms.

The impact of an infection depends on the severity of disease in the population, the number of people affected, and the availability of interventions (for example, available treatments or control measures).

When probability and impact assessments have been completed, these can be combined to determine the overall risk level to the population in question.

3. Communication and outputs

Information gathered through EI informs various routine and reactive outputs. If an incident is deemed to be of public health importance, it is reported to relevant groups and individuals both within UKHSA and across UK government, as required depending on the risk identified. The EIZ team also share and receive EI from their international networks.

Uses of information gathered are outlined below.

3.1 Guidance and incident response

EI gathered by the EIZ team is used to inform relevant public health guidance and maintain up to date disease specific webpages on gov.uk (for example, the Ebola clinical management and guidance collection).

EI is also used for international situational awareness during UKHSA’s responses to outbreaks, for example the multi-country monkeypox outbreak in 2022.

3.2 Reports

The emerging infections monthly summary provides information about significant outbreaks of new and emerging infectious diseases globally, identified through the EIZ team’s EI activities. The report includes a section on new scientific publications of relevance to emerging infections and information about any reports of novel pathogens and diseases identified.

The high consequence infectious diseases (HCID) monthly report summarises information about cases and outbreaks of HCIDs reported globally. The report is publicly available and aims to inform healthcare professionals that may be involved in the identification of HCIDs.

3.3 Informal communications

Information is informally communicated with colleagues within UKHSA and from other UK Government departments on request, and reports on particular international incidents are produced as required.