Abstract Rational The temporal changes of Myxovirus resistance protein A (MxA), a virus-specific biomarker, remain poorly characterized in patients with naturally acquired respiratory viral infections. Methods This prospective study enrolled outpatients with acute respiratory viral infections and conducted 2 to 3 follow-up visits within 14 days. Peripheral blood samples were collected, and MxA levels were quantitatively measured using a fluorescence immunochromatography assay. Symptom severity, virological data, and antiviral treatment regimens were documented. Generalized estimating equation (GEE) models were used to assess the relationships among the kinetics of MxA levels, viral reads measured by targeted next-generation sequencing (tNGS), and symptom severity, as well as the effects of antiviral treatments on MxA trajectories. Results A total of 201 outpatients with viral respiratory infections were included in this study. MxA levels increased sharply following symptom onset, peaked around day 2, and gradually decreased, failing below 50ng/ml by day10. Multivariable GEE models indicated a significant positive correlation between longitudinal changes in viral reads measured by tNGS and MxA levels (B = 18.6; 95% confidence interval CI, 11.1 to 26.1; P = 0.001). Additionally, MxA levels were positively correlated with the mean respiratory symptom scores (B = 0.002; 95% CI, 0.001 to 0.003; P = 0.001). In influenza B patients, MxA levels declined significantly faster in patients treated with baloxavir compared to those treated with oseltamivir (B = -10.8; 95% CI, -17.1 to -4.5; P 0.001). This trend aligned with the changes observed in viral reads via tNGS and symptom improvement. Conclusions Our findings suggest that temporal changes in MxA levels closely correlated with both viral load and symptom severity, suggesting its potential as a biomarker for monitoring infection resolution and evaluating antiviral response in respiratory viral infections. This abstract is funded by: Chinese Academy of Medical Sciences (2023-I2M-C&T-B-119), Zybio Inc. (grant 2023-HX-111), Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (CIFMS 2021-I2M-1-048), and New Cornerstone Science Foundation
Yan et al. (Fri,) studied this question.