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Only some post-acute conditions often attributed to long COVID truly occur more often after SARS-CoV-2 infection than after other viral respiratory diseases, according to a non–peer-reviewed meta-analysis published this week on the preprint server medRxiv.
From June 2024 to April 2025, an international roster of researchers conducted a systematic review and meta-analysis of 14 multicenter cohort studies comparing 24 lingering conditions or symptoms in adults after SARS-CoV-2 infection with those occurring after other acute respiratory viral infections.
Heart rate abnormalities of borderline significance
The included studies were conducted in North America, Asia, Europe, or on multiple continents, and comparator groups most often involved influenza-like illness (ILI), influenza, and respiratory syncytial virus (RSV) in both hospitalized and non-hospitalized patients.
Distinguishing pathogen-specific sequelae from common post-viral syndromes has important implications for patient counselling, risk stratification, health-care planning, and the design of post-infectious surveillance and rehabilitation strategies.
Increased post-COVID risk was noted for pulmonary embolism (relative risk [RR], 1.77), abnormal breathing (RR, 1.59), fatigue or malaise (RR, 1.39), hemorrhagic stroke (RR, 1.23), memory loss/brain fog (RR, 1.34), and palpitations (RR, 1.23); heart rate abnormalities were of borderline significance (RR, 1.24). Pooled estimates of most other outcomes were inconclusive.
No increased risk was seen for anxiety or depression, acute coronary syndrome, cerebrovascular disorders, headache, loss of smell or taste, or sleep problems, which the authors said suggests substantial overlap between long COVID symptom and conditions and those occurring after other respiratory virus infections.
“These findings suggest that post-acute infection syndromes may occur after non-COVID respiratory infections and share many clinical features with post-COVID condition (PCC), whereas SARS-CoV-2 infection may increase the risk of specific thrombotic, autonomic, and neurocognitive outcomes,” the researchers concluded.
“Distinguishing pathogen-specific sequelae from common post-viral syndromes has important implications for patient counselling, risk stratification, health-care planning, and the design of post-infectious surveillance and rehabilitation strategies,” they added.
The study’s limitations were inclusion of mostly retrospective studies, limiting causal inference and introducing potential misclassification and residual confounding, especially for subjective symptoms evaluated long after infection. Also, the lack of stratified data by viral variant, vaccination status, timing of post-acute outcome, and clinical setting limited the findings’ generalizability, the authors noted.