As 2023 faded into 2024, the world passed a somber milestone – the 3-year mark since COVID-19 was declared a global pandemic. While much of society has sought a “return to normal,” for a rapidly growing group of Canadians, COVID-19 continues to inflict daily, disabling symptoms with no clear end in sight. Yet for many COVID survivors, the battle does not necessarily end once they recover from the initial infection. A complex array of lingering symptoms is now recognized as a post-viral syndrome named “long COVID” – and we have only begun scraping the surface of understanding this chronic condition.
This cluster of post-viral effects lasting months to years after initial infection has come to be widely known as “long COVID.” First acknowledged in mid-2020 with early waves of patients, the number of people in Canada living with lingering symptoms has now swollen well into the hundreds of thousands just shy of 2025.
Yet for many COVID survivors, the battle does not necessarily end once they recover from the initial infection. A complex array of lingering symptoms is now recognized as a post-viral syndrome named “long COVID” – and we have only begun scraping the surface of understanding this chronic condition.
In this blog, I explore what experts have uncovered so far about the perplexing phenomenon of long COVID based on early research and patient reporting. We have much left to discover with this “novel” virus and the mysterious aftermath trailing in its wake.
What is Long COVID?
While most people recover fully from COVID-19 within two to six weeks, it became clear early in the pandemic that a significant portion of patients experience symptoms persisting for months or indefinitely after the initial infection resolves. The umbrella term for symptoms lingering over 3-4 weeks after onset is post-acute sequelae of COVID (PASC) more conversationally known as “long COVID.”
These ongoing health issues are diverse, fluctuating, and often disabling for those afflicted. They include fatigue, shortness of breath, brain fog, headaches, heart issues, pain, sensory abnormalities, sleep disruption, fevers, digestive problems, rashes, anxiety, and depression among others. Study criteria and definitions remain variable, though it’s conservatively estimated that 10-30% of COVID survivors deal with long-term symptoms.
Piecemeal Theories on Causes
The underlying biological causes of long COVID have researchers puzzled. Leading theories attempt to connect the dots between disparate symptoms, impacted organs, timescales of onset, waves of relapse and remission, and severity of initial COVID presentation.
A popular hypothesis centers on reservoirs of the virus persisting in tissues like intestinal cells, enabling sustained triggering of inflammatory responses. Autoantibodies or autoimmune reactions trained to attack not just SARS-CoV-2 but the patient’s tissue are another consideration. Microclots that compromise oxygen flow could play a role. Mitochondrial cell damage, activation of dormant viruses like Epstein-Barr, and gut microbe disruption – all remain speculative contributors.
Research reveals some risk factors associated with developing long COVID – hospitalization, older individuals, and the number and severity of early symptoms topping the list. Yet plenty of young, previously healthy people still end up dealing with lingering effects. Ultimately the heterogeneity between patients makes teasing apart singular attributable factors enormously complex.
Long COVID Presents In Different Phases
In studying patients, distinct time frames and categories of lingering symptoms have emerged across what’s likely a spectrum encompassing multiple phenomena rather than one uniform syndrome:
Acute COVID-19: Initial infection lasting beyond 2-4 weeks
Post-acute/Subacute COVID-19: 4 to 12 weeks from onset
Chronic/Long COVID: Persisting after 12+ weeks
Long COVID symptoms also appear to present in phases, fluctuating and even recurring over unpredictable periods:
- Relapsing/remitting symptoms continuing from the acute viral phase
- Waxing/waning symptoms and “waves” of new-onset issues
- Persistent symptoms remaining steady without relief
- Possible eventual recovery or lasting organ damage and disability
Studies slowly but surely adding more clarity are critical. They enable the development of diagnostic criteria, pinpointing biological pathways of disease, finding optimal treatments, identifying those most at risk, determining prognosis, and appropriately allocating healthcare resources for this patient population.
Long COVID symptoms
Long COVID refers to long-term symptoms that can persist for months or years after initially contracting COVID-19, the disease caused by the SARS-CoV-2 virus. Some common long COVID symptoms include:
- Fatigue: This appears to be the most common long COVID symptom. Many people report debilitating fatigue that interferes with daily activities and quality of life.
- Shortness of breath: Difficulty breathing, getting winded easily, or labored breathing during basic physical activities may occur.
- Cognitive dysfunction (“brain fog”): Issues with memory, concentration, mental clarity and processing speed have been reported.
- Persistent cough: A lingering cough after the typical COVID recovery period can happen after even a mild initial infection.
- Heart palpitations and chest pain: Some survivors experience increased heart rate, irregular heart rhythms, or pain lasting for months.
- Headaches: Frequent headaches are a commonly reported neurological symptom. Migraine characteristics have been noted for some.
- Loss of smell and taste: Though these senses usually return within weeks for mild COVID cases, some proportion of survivors report an ongoing partial or complete loss.
- Muscle aches and joint pain: Nonspecific muscle and joint pain can persist long after an initial infection.
The variety and combinations of long COVID symptoms vary significantly among patients. The disease is still being actively studied to understand the full scope and diversity of long-term effects.
Never before have researchers and healthcare providers been challenged to understand such a new ubiquitous post-viral entity Larger studies like the NIH’s $470 million RECOVER initiative focused specifically on long COVID will hopefully provide accelerated insight. High-profile acknowledgment may also help validate patient experiences and hasten assistance.
For now, providers emphasize that long COVID patients are neither anomalies nor hypochondriacs. Extensive validation, specialist referrals, rehabilitation support, and anti-inflammatory lifestyle adjustment form the crux of recommended care while we await scientific revelation on causation.
As researchers chip away, long COVID stands as a sobering reminder that medicine does not yet have all the answers – especially for multi-systemic neuroimmune diseases. Chronic illnesses impacting as many as 50 million Americans are subject to similar doubt when standard labs and imaging fail to match patients’ suffering.
The COVID-19 pandemic brought this discord into mainstream focus by burdening even formerly healthy, young professionals – rather than just the historically neglected chronically ill patient demographic. The urgency and publicity of long-term COVID impacts will meaningfully direct scientific attention toward a better understanding of post-viral syndromes and complex, chronic conditions at large after decades of inadequate investment.
For the time being, long COVID remains a polarizing clinical mystery and public health crisis. Causation theories abound across biology, virology, immunology, and more as patients develop their symptom management strategies. Until science catches up with living inside this emerging landscape of long-term disability, management focuses on validating patient realities, slowing spread to limit new cases, and supporting those already irrevocably affected by a virus that for many has yet to stop inflicting damage long after the initial infection faded.