Abstract

Background: The complex immunopathological events and immune residues induced by the coronavirus disease 2019 (COVID-19), lymphocyte damage and immune retention play central roles in the long novel coronavirus.

Objective: To elucidate the immune mechanism underlying the occurrence and persistence of COVID-19 symptoms, it is urgent to explore easy-to-detect biomarkers, diagnostic biomarkers and potential therapeutic targets, the mechanism of lymphocyte damage, the manifestation of immune retention and how their interactions lead to prolonged duration of COVID-19 symptoms.

Methods: The preepidemic group from 2015--2017, the epidemic group from 2021--2024, the relaxed public health intervention group from 2023--2024, and the other nonradiological workers’ occupational group composed the control group. The white blood cell count, lymphocyte count, neutrophil-to-lymphocyte ratio (NLR), lymphocyte ratio (LYM%) and detection rate of lymphocyte ratios >40 were also analysed.

Results: From 2021--2024, the NLR value continues to decrease, and the LYM percentage average continues to increase. The detection rate of a lymphocyte ratio >40 was greater from 2022--2024, and the difference was statistically significant compared with that in 2021 (P<0.01). Neutrophil counts continued to decrease, and lymphocyte counts continued to increase.

Conclusion: Globally, long COVID-19 patients show significant clinical and immunological heterogeneity. The average LYM percentage and LYM percentage >40% were associated with immune status. Repairing the immune system damaged by the novel coronavirus can stop the continuation of the outbreak and can also serve as an immunotherapy target to control long-term COVID-19.