Updated on 05/01/2024

Long Covid: What is Long Covid and How Common is It? What are the Symptoms? Who is at Risk? What are the Neurological Effects?

Photo: Dilek Necioğlu Örken

The disease caused by SARS-CoV-2 manifests clinically in various ways. It can range from being asymptomatic or causing mild upper and lower respiratory tract disease to a life-threatening condition with multisystem involvement. Most cases resolve within 2-4 weeks. Evidence regarding the long-term effects of the disease is increasing day by day.

How Common is Long Covid?

Approximately 65 million people worldwide suffer from Long Covid. The incidence is around 10-30% in individuals with outpatient disease, 50-70% in hospitalized patients, and around 10-12% in vaccinated individuals.

What is Long Covid?

Long Covid is defined as the presence of symptoms that persist or develop after 4 weeks of the initial diagnosis of Covid-19 and cannot be explained by any other diagnosis.

What are the Symptoms of Long Covid?

Long Covid can present with a wide range of symptoms, including shortness of breath, cough, chest pain, palpitations, fatigue, muscle pain (myalgia), loss of taste or smell, cognitive impairments (memory loss), and sleep disturbances. Long Covid can lead to multiple diseases, including cardiovascular and cerebrovascular diseases, thrombotic events, type 2 diabetes, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and dysautonomia, particularly causing postural orthostatic tachycardia syndrome (POTS). Symptoms can persist for years, and newly developed POTS and ME/CFS can be lifelong in some cases.

Who is at Risk?

Risk factors for Long Covid include:

1. Advanced age
2. Female gender
3. Chronic conditions such as cardiovascular disease, chronic lung diseases, kidney diseases, hypertension, and diabetes
4. Obesity
5. Severity of the initial illness

What are the Neurological Effects of Long Covid?

Long Covid can have neurological effects such as sensory-motor symptoms, memory loss and cognitive impairment, paresthesias, dizziness and balance disturbances, sensitivity to sound and light, loss of taste and smell, autonomic dysfunction, tinnitus, and hearing loss. A meta-analysis found that fatigue was present in 32% and cognitive impairment in 22% of individuals even after 12 weeks. Mental disorders (brain fog) have been identified in 1.3 million individuals to date. Anxiety and depression tend to return to normal over time, but there is an increased risk of persistence of neurocognitive conditions like brain fog.

Unfortunately, there is currently no definitive treatment for Long Covid. However, treatments targeting the symptoms it causes are possible.

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2. Hannah E. Davis ve ark. Long COVID: major findings, mechanisms and recommendations. Nature Reviews Microbiology 2023; (21): 133–146.
3. Laura McWhirter What is brain fog? J Neurol Neurosurg Psychiatry 2023;94:321–325.

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