High Consequence Infectious Diseases: Understanding HCIDs in the UK

In the dimly lit corridors of the Royal Free London Hospital, a virus silently wreaked havoc, claiming lives and straining healthcare resources. Just a few years ago, during an Ebola outbreak in West Africa, the specter of High Consequence Infectious Diseases (HCIDs) loomed ever larger, revealing the delicate balance between global travel and the spread of deadly pathogens. As the UK grappled with the impact of diseases that could insidiously infiltrate its borders, the definition and classification of HCIDs became critical in protecting public health.

Definition of HCID

HCID in the UK is defined by a stringent set of criteria that underscores the potential danger these diseases pose:

• Acute infectious disease with a high case-fatality rate
• Limited effective prophylaxis or treatment
• Challenges in rapid recognition and detection
• Community and healthcare settings can serve as transmission hubs
• Mandated enhanced responses from healthcare systems and the population

Dr. Caroline Westwood, an epidemiologist at the London School of Hygiene & Tropical Medicine, emphasizes the importance of these criteria. “HCIDs require an urgent, coordinated response, as they often evolve rapidly and can overwhelm healthcare systems if not managed properly,” she says. The combination of high severity and the urgent need for public health interventions makes these diseases particularly menacing.

Classification of HCIDs

To further dissect these threats, HCIDs are classified into two primary categories based on their transmission methods:

• Contact HCIDs: Spread through direct contact with infected individuals or contaminated materials.

• Airborne HCIDs: Transmitted via respiratory droplets, often accompanied by contact pathways.

List of High Consequence Infectious Diseases

Among the diseases classified as HCIDs, the following have been identified by the UK’s public health agencies:

Contact HCIDs

• Argentine haemorrhagic fever (Junin virus)
• Bolivian haemorrhagic fever (Machupo virus)
• Crimean Congo haemorrhagic fever (CCHF)
• Ebola virus disease (EBOD)
• Lassa fever
• Lujo virus disease
• Marburg virus disease (MVD)
• Severe fever with thrombocytopaenia syndrome (SFTS)

Airborne HCIDs

• Andes virus infection (hantavirus)
• Avian influenza (H7N9 and H5N1)
• Middle East respiratory syndrome (MERS)
• Nipah virus infection
• Pneumonic plague (Yersinia pestis)

According to a recent article in the Journal of Infectious Disease Research, the prevalence of airborne HCIDs poses unique challenges for at-risk populations. “Even in well-resourced countries like the UK, the threat of airborne pathogens remains a significant concern,” says Dr. Samuel Liu, a virologist. “Effective surveillance and rapid response are imperative to contain outbreaks.”

Status of COVID-19

As of March 19, 2020, COVID-19 transitioned from an HCID classification to a more manageable infectious disease status. Initial assessments, based on early mortality rates and the inadequate understanding of the virus, led to its temporary designation as an HCID. However, as epidemiological data gradually revealed lower overall mortality rates and enhanced clinical awareness, the Advisory Committee on Dangerous Pathogens (ACDP) revised its classification.

Dr. Isabelle Mendez, a consultant in infectious diseases, explains: “The data we have now reflects a complex picture. While COVID-19 can be lethal, many of the affected individuals recover, fundamentally altering its risk profile compared to diseases like Ebola or MERS.”

Status of Mpox

In June 2022, the MPXV virus linked to community transmission was no longer considered an HCID, reflecting a significant drop in cases. Still, the strain responsible for severe cases remained classified as potentially high consequence. “We need to stay vigilant,” states Dr. Aamina Roy, a public health analyst. “The reassessment of mpox illustrates how context and transmission dynamics are paramount in defining HCID risk.”

HCIDs in the UK

Instances of HCIDs in the UK are infrequent and primarily associated with international travel. Healthcare practitioners remain vigilant as sporadic cases emerge, emphasizing the importance of rapid identification and control measures. The UK has successfully managed cases of several HCIDs, including Lassa fever, EBOD, and MERS, with secondary transmission of MERS notable despite its rarity.

HCID Risks by Country

For healthcare professionals, understanding the HCID risk varies greatly by country. Resources detailing these risks can inform travel health advice and help prepare practitioners for potential cases upon return to the UK.

Infection Prevention and Control in Healthcare Settings

Infection prevention and control are paramount for managing suspected HCID cases across both specialist and non-specialist facilities. Guidance on safety measures and protocols is critical in protecting healthcare providers and the community at large.

Specialist Advice for Healthcare Professionals

The Imported Fever Service (IFS) remains an invaluable resource, providing 24/7 support for clinicians managing suspected HCID cases. “Even a single case can have broader implications for public health,” emphasizes Dr. Mark Roberts, the IFS director. “Prompt communication is essential for effective management.”

Hospital Management of Confirmed HCID Cases

Once confirmed, HCID cases are rapidly transferred to designated treatment centres, such as the Royal Free London High Level Isolation Unit. These centres serve both adult and pediatric populations, ensuring specialized care tailored to the needs of each patient.

Despite the infrequency of HCIDs within the UK, the risk of their emergence and potential for outbreaks demands an unwavering commitment to public health vigilance. As global travel continues and new infectious diseases are identified, understanding and managing HCIDs will be critical in safeguarding health at both national and global levels. In this ever-evolving landscape, the collaboration among public health agencies, healthcare providers, and researchers remains a lifeline in the face of infectious threats.

Source: www.gov.uk