Assessing for Long COVID
If your patient has symptoms persisting more than 12 weeks after confirmed COVID-19 infection without an alternative explanation, this meets the diagnostic criteria for long COVID. 1
Diagnostic Criteria
Long COVID is defined as one or more symptoms persisting or relapsing/remitting for more than 12 weeks since acute COVID-19 diagnosis, without an alternative explanation. 1 This is a diagnosis of exclusion—you must first rule out other serious conditions before attributing symptoms to long COVID. 1
Time-Based Classification:
- Post-acute COVID: Symptoms from 4-12 weeks after confirmed infection 1
- Long COVID: Symptoms persisting beyond 12 weeks 1
Most Common Symptom Patterns
The most frequently reported symptoms that should raise suspicion for long COVID include: 1
- Fatigue (31-58% of cases) 1
- Dyspnea/shortness of breath (24-40% of cases) 1
- Cognitive impairment/"brain fog" (12-35% of cases) 1
- Sleep disturbances/insomnia (11-44% of cases) 1, 2
- Musculoskeletal pain (9-19% of cases) 1
- Anosmia/dysgeusia (10-22% of cases) 1
- Cough (7-29% of cases) 1
- Chest pain (6-17% of cases) 1
Symptom Clusters to Recognize
Long COVID symptoms tend to cluster into five distinct patterns: 3
- Gastrointestinal cluster: Nausea, abdominal pain, loss of appetite, heartburn, constipation 1, 3
- Musculoskeletal cluster: Joint pain, myalgia, body aches (more common in older patients and mixed race individuals) 3
- Neurocognitive cluster: Brain fog, memory issues, confusion, depression, anxiety (strongly associated with mental health screening positivity) 3
- Airway cluster: Cough, throat pain 3
- Cardiopulmonary cluster: Dyspnea, chest pain, palpitations 3
Critical Risk Factors
Two consistent risk factors emerge across all studies: 1
- Female sex: Women have 1.5-2 fold increased odds (OR 1.3-5) of developing long COVID 1, 4
- Severe acute COVID-19: Hospitalization increases odds 4.5-fold (OR 4.51) 1, 3
Additional risk factors include: 3
- Poorer pre-COVID self-rated health (OR 0.75) 3
- More than five early symptoms during acute infection 5
- Early dyspnea during acute phase 5
Important caveat: Long COVID can affect all individuals regardless of acute disease severity—even those with mild-to-moderate initial illness can develop persistent symptoms. 1, 4
Conditions You Must Rule Out First
Before diagnosing long COVID, systematically exclude: 1
- Thromboembolic events (pulmonary embolism, deep vein thrombosis) 1
- Myocarditis 1
- Encephalitis 1
- Previously overlooked malignancy 1
- Thyroiditis 1
- Iatrogenic causes or complications from acute COVID-19 treatment 1
When to Refer for Medical Assessment
Refer any patient with symptoms lasting more than 12 weeks after acute COVID-19 for formal medical evaluation. 1
For patients with symptoms between 4-12 weeks, assess on a case-by-case basis according to: 1
- Severity of symptoms 1
- Trajectory of symptoms (worsening vs. stable vs. improving) 1
- Impact on daily functioning and work capacity 1
Temporal Patterns to Recognize
Symptom onset and progression vary by type: 1
- Neurological symptoms often have delayed onset of weeks to months (43% report cognitive symptoms starting ≥1 month post-infection) 1
- Gastrointestinal and respiratory symptoms are more likely to resolve over time 1
- Neurocognitive symptoms tend to worsen over time and persist longer 1
- Musculoskeletal pain, paresthesia, hair loss, and blurry vision are more common at 1 year than at 2 months 1
- Parosmia has average onset of 3 months post-infection but often decreases over time 1
Quality of Life Impact
57% of patients with symptoms persisting beyond 12 weeks report decreased quality of life. 1 Long COVID significantly affects: 1, 3
- Return to work (45.2% require reduced work schedule) 6
- Daily activities and functioning 1
- Mental health (>20% screen positive for depression and/or anxiety) 3
Special Populations
Children
Long COVID affects children of all ages with similar symptom patterns to adults, including fatigue, cognitive dysfunction, headaches, and orthostatic intolerance. 1 Children may also develop rare complications including myocarditis, pulmonary embolism, and type 1 diabetes. 1
Post-ICU Patients
For critically ill patients, distinguish between long COVID and post-intensive care syndrome, which encompasses physical, cognitive, and psychiatric abnormalities after critical illness. 1 This distinction is often difficult but clinically important. 1
Prognosis
85% of patients with symptoms at 2 months still report symptoms at 1 year. 1 Few patients demonstrate full recovery, and future prognosis remains uncertain. 1 Conditions like ME/CFS and dysautonomia, which share features with long COVID, are generally lifelong. 1