Post-COVID-19 syndrome and low-grade inflammation: exploring gender and occupational inequalities in a retrospective cohort study.

Background: To investigate the association between post-coronavirus disease 2019 (COVID-19) syndrome (PCS) and chronic low-grade inflammation (LGI) in blood cells in 4108 mild COVID-19 patients.

Methods: The data were collected within 12-24 weeks before and 24 weeks after COVID-19 infection. The χ2 test was utilized to analyse the differences between two groups. The relationship between PCS symptoms and inflammatory cells was analysed by logistic regression analysis.

Results: The most common PCS symptom was cough, reported as 'occasionally' by 33.47% and 'frequently' by 5.92%. Women exhibited more severe symptoms than men. Among healthcare workers, palpitations were more pronounced (0.76% versus 0.35%), while the prevalence of other PCS symptoms was lower compared with non-healthcare workers. After adjusting for confounding factors, women showed a higher risk of five types of PCS, and healthcare workers had a greater risk of fatigue and dizziness compared with the non-healthcare worker. Fatigue was associated with lymphocytes, monocytes and the neutrophil:lymphocyte ratio (NLR). Cough correlated with high-sensitivity C-reactive protein (hs-CRP), NLR and the platelet:lymphocyte ratio (PLR). Dizziness was linked to hs-CRP, NLR and PLR. Palpitations correlated with hs-CRP.

Conclusions: Our findings suggest that PCS symptoms may be associated with LGI in peripheral blood cells, gender and occupational inequalities, warranting further investigation.