Low serum selenium combined with SELENOP-autoantibodies are associated with persistent fatigue after SARS-CoV-2 infection.

BACKGROUND

Cytokines found during post-acute sequelae after COVID-19 are known to reduce selenoprotein biosynthesis, raising the question whether low selenium, impaired selenoprotein P (SELENOP) production, and autoantibodies to SELENOP (SELENOP-aAb) are associated with persistent fatigue after SARS-CoV-2 infection.

METHODS

Persistent symptoms and selenium determinants were assessed on average 21.9 months after a PCR-verified SARS-CoV-2 infection in a cross-sectional population-based study (n = 750 adults, 54.1% female). Study participants were categorized based on the presence of low selenium levels (<70 μg/L), low SELENOP levels (<4.1 mg/L), and SELENOP-aAb positivity (≥3.0 BI). Regression models were fitted to assess associations between selenium determinants and persistent fatigue, adjusted for potential confounders.

FINDINGS: Persistent fatigue was self-reported by 23.1% (n = 173) of participants. Low serum selenium was measured in 63.7% (n = 478), low SELENOP in 89.6% (n = 672), and elevated SELENOP-aAb in 3.9% (n = 29). A combination of low selenium and elevated SELENOP-aAb was found in 1.9% (n = 14) participants, a combination of low SELENOP and SELENOP-aAb in 3.2% (n = 24). Individually, all three selenium-related determinants showed no strong indication for an association with persistent fatigue. However, the combination of selenium deficiency and SELENOP-aAb positivity showed a prevalence ratio of 2.16 (95%-CI: 1.13-4.11), and the combination of SELENOP deficiency and SELENOP-aAb positivity a prevalence ratio of 2.15 (95% Cl: 1.01; 4.60) compared to the reference group.

INTERPRETATION: The study indicates that in a fraction of COVID-19 affected participants low selenium/SELENOP levels in combination with SELENOP-specific autoantibodies are associated with a two times higher prevalence of persistent fatigue after SARS-CoV-2 infection.