Objectives: Studies reported associations of inflammatory markers with the severity of COVID-19, but conclusions were inconsistent. We aimed to provide an overview of the association of inflammatory markers with the severity of COVID-19. Methods: We searched PubMed, Embase, Cochrane Library, Wanfang and China National Knowledge Infrastructure (CNKI) database until March 20, 2020. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were pooled using random or fixed-effects models. Results: A total of 16 studies comprising 3962 patients with COVID-19 were included in our analysis. Random-effect results demonstrated that patients with COVID-19 in the nonsevere group had lower levels for CRP (WMD = À41.78 mg/l, 95% CI = [À52.43, À31.13], P < 0.001), PCT (WMD = À0.13 ng/ml, 95% CI = [À0.20, À0.05], P < 0.001), IL-6 (WMD = À21.32 ng/l, 95% CI = [À28.34, À14.31], P < 0.001), ESR (WMD = À8 mm/h, 95% CI = [À14, À2], P = 0.005), SAA (WMD = À43.35 mg/ml, 95% CI = [À80.85, À5.85], P = 0.020) and serum ferritin (WMD = À398.80 mg/l, 95% CI = [À625.89, À171.71], P < 0.001), compared with those in the severe group. Moreover, survivors had a lower level of IL-6 than non-survivors (WMD = À4.80 ng/ml, 95% CI = [À5.87, À3.73], P < 0.001). These results were consistent through sensitivity analysis and publication bias assessment. Conclusions: The meta-analysis highlights the association of inflammatory markers with the severity of COVID-19. Measurement of inflammatory markers might assist clinicians to monitor and evaluate the severity and prognosis of COVID-19.

Absolute state-selected cross sections for the reactions O+(4S,2D,2P)+N2→N2++O, NO++N, and N++NO (and/or N++N+O) have been measured in the center-of-mass collision energy (Ec.m.) range of 0.06–40 eV employing the differential retarding potential method and the O+(2D) and O+(2P) ion state-selection schemes we developed recently. Charge transfer is the overwhelming product channel for the O+(2D)+N2 and O+(2P)+N2 reactions. Contrary to the results of previous experiments, the charge transfer cross sections for O+(2P)+N2 are found to be 30%–100% greater than those for O+(2D)+N2. This observation suggests that N2 is an excellent quenching gas for O+(2D,2P). While the Ec.m. dependencies for the cross sections of NO+ from O+(4S)+N2 and O+(2D)+N2 are similar, exhibiting a broad maximum in the Ec.m. range of 1.5–8 eV, the cross section for NO+ from O+(2P)+N2 is found to decrease as Ec.m. is decreased. The N+ signal observed in the O+(4S)+N2 reaction is attributed to the formation of N++N+O. The pathway of O++N2→N++NO to generate N+ is strongly suggested as the major channel in the reactions of O+(2D,2P)+N2, as evidenced by the observation of N+ well below the thermochemical thresholds of O+(2D,2P)+N2→N++N+O.