Brain, behavior, & immunity - healthOct 10, 2025

Inflammation linked to fatigue after COVID-19

Long Covid Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 27, 2026

Abstract

Essence

Stronger acute inflammatory signals in hospitalized COVID-19 patients were linked to more physical and total fatigue 6-9 months later.

Evidence

A longitudinal observational biomarker analysis of 54 hospitalized patients related acute serum immune markers to chronic fatigue dimensions after infection.

Caveat

The small hospitalized cohort and associative models do not establish causality or generalize to milder non-hospitalized COVID-19.

Simplified

The biological mechanisms underlying objective and subjective fatigue in post-COVID syndrome remain unclear. This study investigates whether immune responses during the acute phase of SARS-CoV-2 infection predict fatigue dimensions 6-9 months post-infection. We analyzed serum immune markers from 54 hospitalized patients (mean age: 58.69 ± 10.90 yrs; female: 31 %) and assessed their association with chronic fatigue using general linear mixed models. Elevated levels of IL-1RA, IFNγ, TNFα, and monocyte percentage during acute infection predicted increased physical and total fatigue. Additionally, higher TNFα levels (r = -0.40, = .019) correlated with reduced awareness of cognitive fatigue. These findings highlight the role of acute inflammation in the persistence of post-COVID fatigue. p

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