Physical and cognitive impact following SARS-CoV-2 infection in a large population-based case-control study

Area of Science:

• Infectious Diseases
• Post-Acute Sequelae of COVID-19
• Public Health

Background:

• Persistent symptoms following SARS-CoV-2 infection are frequently reported.
• The correlation between subjective symptoms and objective clinical measures post-infection remains unclear.
• Understanding long COVID requires evaluating both self-reported symptoms and objective health parameters.

Purpose of the Study:

• To investigate the association between prior SARS-CoV-2 infection and a wide range of symptoms.
• To compare objective physical and cognitive measures between individuals with confirmed SARS-CoV-2 infection and control groups.
• To estimate the prevalence of long COVID symptoms months after initial infection.

Main Methods:

• A cohort study involving 1706 individuals with confirmed SARS-CoV-2 infection (cases) and 619 contemporary/13,779 historical controls.
• Cases were assessed 5-18 months post-infection, comparing 88 symptoms and various physical/cognitive measures.
• Objective measures included smell/taste tests, grip strength, memory recall, heart rate, blood pressure, and blood biomarkers.

Main Results:

• Forty-one of 88 assessed symptoms were significantly associated with prior SARS-CoV-2 infection, notably disturbed smell/taste, memory issues, and dyspnea.
• Objective assessments revealed poorer smell/taste, reduced grip strength, and impaired memory recall in cases, though differences were small.
• No significant differences were found in other objective measures, including cardiovascular, respiratory, inflammatory, cardiac, liver, or kidney function markers, nor in anxiety or depression levels.
• The estimated prevalence of long COVID was 7% at a median of 8 months post-infection.

Conclusions:

• Diverse symptoms persist months after SARS-CoV-2 infection, but objective findings often do not align with self-reported issues.
• The discrepancy suggests complex post-infection pathophysiology not fully captured by conventional objective tests.
• Standard clinical assessments may have limited utility in definitively linking symptoms to past SARS-CoV-2 infection.