Health Application Lightweight Protocol (HALO): The Immune System of Digital Health

Welcome back to Canada Health Infoway’s Anatomy of a Standard series, where we explore the essential digital health standards that power Canada’s healthcare system.

Just as the body’s vital systems rely on well-coordinated systems to function properly, digital health standards work together to ensure health information flows securely and efficiently. A digital health data exchange standard is a set of agreed-upon rules and specifications that ensure different healthcare systems can share and understand patient information in a secure and consistent way to support seamless, Connected Care across Canada.

So far, we’ve explored:

• The Pan-Canadian Patient Summary (PS-CA) as the circulatory system, delivering essential health information where and when it’s needed.

• CA:eReC (eReferral/eConsult) as the nervous system, enabling coordinated, real-time communication between providers.

If you’ve missed any of the previous articles, click the links above to catch up!

The ‘Immune System’ within Canada’s Digital Healthcare System

The immune system serves as the body’s first line of defense — detecting, responding to, and adapting to threats to maintain health and balance. Without it, even minor exposure to bacteria, viruses, or toxins can compromise overall function.

Canada’s digital healthcare system faces similar obstacles. Clinicians rely on their clinical systems, like electronic medical records (EMRs), to ensure they have access to relevant patient health information at the point-of-care. Access to accurate and timely patient data help clinicians to make more informed decisions for improved patient outcomes.

Just as the immune system filters out harmful agents while promoting healing and coordination among biological systems, clinicians rely on their clinical systems to connect seamlessly with one another for efficient, seamless, and coordinated care delivery.

This is where the Health Application Lightweight Protocol (HALO) comes in.

What is HALO?

HALO is a national framework designed to enable seamless integration of digital health applications within EMRs and other point-of-care (POC) solutions.

Once an EMR adopts the HALO standard, HALO-compliant web applications can launch directly within the EMR through a single interface. This allows secure, two-way data exchange between systems and enables apps to 'communicate' with each other. As a result, clinicians gain streamlined access to a range of digital tools for services like sharing a Patient Summary, submitting eReferrals, or initiating eConsults.

As Canada advances toward a more connected healthcare system, HALO can play a critical role in unlocking the full potential of health data to enable truly Connected Care.

Built on existing standards, HALO helps to advance Connected Care by:

• Enabling secure, real-time data exchange across platforms and systems

• Reducing duplication and administrative burden for healthcare providers

• Embedding digital tools into clinical workflows to streamline care delivery

• Improving access to patient information at the point of care

Through consistent and secure information flow, HALO ensures clinicians have the right information at the right time, placing patients at the center of a more connected, efficient healthcare system.

HALO as the Immune System of Digital Health Infrastructure

Much like how the immune system supports long-term health and prevents illness, HALO provides a secure, flexible foundation that enables digital health innovation while maintaining system stability and security.

For clinicians, HALO manages data exchange, ensuring only approved, standards-compliant applications can integrate into a clinician’s EMR, safeguarding system integrity — just as the immune system identifies, filters, and adapts to threats to protect and support healing.

Thanks to its adaptive memory, the immune system learns from past exposures, allowing it to respond more swiftly and effectively to repeat threats, enhancing its resilience over time. Similarly, as digital health adoption grows, HALO evolves to ensure new solutions can integrate seamlessly into clinical workflows without disruption — supporting long-term system resilience while maintaining interoperability, security, and compliance with national standards.

The Challenge: Siloed Health Information

In the fast-paced environment of clinical care, providers depend on a wide range of digital solutions to complete essential tasks, like accessing patient information, initiating referrals, and updating medications.

Digital health systems should support this work by enabling more efficient and seamless care delivery. However, a lack of interoperability between systems means that critical patient information is not always readily accessible when and where it’s needed. In fact, recent data found that 35% of physicians spend two or more extra hours each day searching for patient information they feel should already be at their fingertips, with 44% reporting some level of burnout as a result.

Without integrated, interoperable digital health data, patient information remains siloed across different clinical systems, leading to unnecessary administrative burden, disrupted workflows, and gaps in access to the data clinicians need to deliver timely, high-quality care.

The Solution: HALO Transforming Digital Health Infrastructure

With HALO, clinicians can complete essential tasks, like accessing patient records, updating medications, or sending eReferrals, within a single interface, more quickly and with fewer clicks, all without disrupting their workflow.

Just as a strong immune system protects the body and keeps it functioning smoothly, HALO empowers EMRs to operate efficiently, supporting clinicians with interoperable digital tools that coordinate care and respond to evolving needs.

The impact at the point of care is significant. HALO streamlines clinical workflows, reduces administrative burden, and improves access to real-time patient information. As a result, clinicians can spend less time navigating fragmented systems and more time delivering care. This also strengthens collaboration between clinicians by making it easier for them to exchange, share, and receive data across health information systems.

While the short-term benefits for clinicians are clear, HALO also plays a vital long-term role by accelerating the adoption of digital health solutions. It helps turn the vision of interoperability into a practical, day-to-day reality across clinical settings.

Importantly, the benefits of HALO extend beyond clinicians. For patients, it can mean more coordinated, efficient care and potentially shorter wait times. For provincial and territorial health systems, it can enable faster rollout of digital tools, reduce duplicate testing, and break down data silos. And for vendors and developers, HALO can simplify EMR integrations, lower development costs, and create a more level playing field for innovators of all sizes.

Looking Ahead

Canada is continuing to advance HALO through collaborative pilot projects and national innovation events. With leadership from Canada Health Infoway and support from jurisdictional and vendor partners across the country, HALO is being piloted to integrate digital health solutions, like eReferrals, directly into EMRs, enhancing interoperability and streamlining clinical workflows.

HALO was also a focal point at Plugathon 2025, a national event dedicated to exploring emerging interoperability technologies. Within the Canadian Interoperability track, HALO was showcased alongside other pan-Canadian specifications, providing a platform for developers, standards experts, and health system leaders to collaborate on refining HALO's framework and aligning it with real-world clinical needs.

These coordinated efforts highlight HALO’s potential to transform digital health integration across clinical settings, positioning it as a foundational element of a more resilient, connected, and efficient digital health ecosystem in Canada.

Stay tuned for the next article in our Anatomy of a Standard series, where we’ll explore another critical digital health standard and its role in Canada’s healthcare ecosystem.