Long COVID

Overview

Long COVID, also known as post-acute sequelae of SARS-CoV-2 infection (PASC), is a condition in which individuals experience ongoing or new health problems for weeks or months after the initial COVID-19 infection has resolved. While most people recover from COVID-19 within a few weeks, some continue to suffer from a range of symptoms that can affect multiple organ systems. Long COVID can occur regardless of the severity of the initial infection and affects both previously healthy individuals and those with pre-existing conditions.

Causes

The exact cause of Long COVID is not fully understood, but several mechanisms are believed to contribute to its development:

• Persistent inflammation – ongoing immune system activation may damage tissues and organs

• Viral persistence – lingering viral particles in certain tissues may trigger symptoms

• Autoimmune response – the virus may cause the immune system to attack the body’s own tissues

• Nervous system dysfunction – including dysautonomia, which can affect heart rate, blood pressure, and digestion

• Organ damage – caused by the initial infection, particularly in the lungs, heart, or brain

Long COVID is not limited to hospitalized or severely ill patients—it can also occur in those with mild or asymptomatic initial infections.

Symptoms

Symptoms of Long COVID vary widely and can affect multiple body systems. They may fluctuate over time and range from mild to debilitating. Common symptoms include:

• Fatigue – persistent exhaustion that is not relieved by rest

• Shortness of breath – even with minimal exertion

• Brain fog – problems with memory, concentration, and mental clarity

• Chest pain or palpitations

• Joint and muscle pain

• Sleep disturbances

• Loss of taste or smell – persisting after acute illness

• Anxiety and depression

• Digestive issues – such as nausea, diarrhea, or abdominal pain

• Post-exertional malaise (PEM) – worsening of symptoms after physical or mental activity

Some individuals also develop new conditions such as diabetes, cardiovascular issues, or autoimmune diseases after COVID-19.

Diagnosis

There is no single test to diagnose Long COVID. Diagnosis is made based on medical history, symptom duration, and the exclusion of other conditions. Diagnostic steps may include:

• Detailed symptom assessment – including timelines and severity

• Physical examination – to check for signs of organ involvement

• Blood tests – to rule out other causes such as anemia, thyroid issues, or inflammation

• Imaging – such as chest X-rays, CT scans, or echocardiograms for respiratory or cardiac symptoms

• Neurocognitive evaluation – for patients with brain fog or mental health symptoms

Clinicians may use validated tools like the Post-COVID Functional Status (PCFS) scale to assess impact on daily life.

Treatment

There is no universal treatment for Long COVID; care is supportive and based on the individual's symptoms and needs. A multidisciplinary approach is often required. Treatment strategies include:

• Symptom-specific medications – such as pain relievers, antidepressants, or inhalers

• Pulmonary rehabilitation – for breathing difficulties

• Cognitive rehabilitation – for brain fog and memory issues

• Physical therapy – to address muscle weakness and mobility

• Pacing and energy management – especially for those with post-exertional malaise

• Mental health support – including counseling and psychiatric care when needed

Long COVID clinics, often affiliated with hospitals or academic centers, provide coordinated care from multiple specialists.

Prognosis

The prognosis of Long COVID is highly variable. Many people experience gradual improvement over time, but recovery can take months or longer. Some individuals make a full recovery, while others may have persistent or relapsing symptoms. Early intervention, supportive care, and regular follow-up can improve outcomes. Ongoing research aims to better understand the condition and develop targeted treatments.