Pandemic vs endemic: the power of a word
How we use terms like pandemic and endemic intersects with global health inequities in our responses to infectious disease threats.
On March 11th 2020, WHO Director-General Tedros Adhanom Ghebreyesus announced:
"We are deeply concerned both by the alarming levels of spread and severity, and by the alarming levels of inaction. We have therefore made the assessment that COVID-19 can be characterized as a pandemic.”
This declaration appears to have been as much a political call as a technical one; a cattle-prod to galvanize a sluggish and disparate response into a global emergency effort.
There are politics not only around when we start using the word pandemic, but also when we stop or transition to endemic disease – one consistently present in locations or populations, with predictable or cyclical patterns of activity.
A pandemic ends when people stop paying attention to it.John M Barry
Consider how we differentiate between a pandemic and an endemic disease with global distribution and sporadic outbreaks, for example tuberculosis.
Defining characteristics of a pandemic include:
- suddenness, speed, and synchronicity of global disease spread
- how far the disease outstrips our ability to understand, predict, and control it
- associated disruption that is acute and widespread
Tuberculosis spreads consistently but slowly, so outbreaks do not follow such a rapid sequential or synchronous pattern between regions. Nonetheless, each year around 10 million people contract tuberculosis, and around 1.5 million die from it. Its epidemiology and clinical implications are predictable and well-understood. Among the things we understand is that it disproportionately affects the poor, children under 5, is increasingly appearing in treatment-resistant forms, and is responsible for 1 in 3 deaths of people with HIV.
In high-resource countries there are well-established and effective measures in place to control and treat it. However in many resource-constrained settings, tuberculosis has demonstrably outstripped the capacity to control it for many decades. In such contexts, where the control of prevalent and life-threatening infectious diseases is so out of reach that they have become part of life, acute disruption associated with major public health crisis responses is indeed absent.
Endemic diseases instead cause chronic, often unmeasured disruption in low-resource settings associated with loss of economic potential, continual strain on already under-resourced health systems, long-term morbidity and disability, ongoing social stigma and discrimination, and other pernicious impacts. Such chronic disruption might be less visible, but it is ultimately more damaging.
These contrasts are starker when it comes to management of neglected zoonotic diseases in domestic animals and livestock. Veterinary care is often entirely inaccessible, and the poorest farming communities bear the costs both in terms of their livelihoods and their own health.
Endemic infectious and zoonotic diseases represent a chronic health burden in many parts of the world that ultimately dwarfs the impact even of COVID-19. These are diseases of poverty and inequity; they are preventable and treatable anywhere that decent healthcare, veterinary care, nutrition, and sanitation is accessible, affordable, and inclusive.
We've seen the power of the word pandemic, and the urgency and scale our global response to it can take on. Considering infectious diseases of poverty as endemic should not mean we accept or normalize their continued prevalence and impact in low-resource settings - just because they are not pandemics, does not mean they are not emergencies.
Dr Anna Barrett is a Senior Technical Advisor in the Nossal Institute’s One Health team. Anna is part of the teaching team delivering our Pandemic Preparedness and Response subject.