ABSTRACT
Aims and objectives: Multiple studies have suggested that neutrophil-lymphocyte ratio (NLR) derived from differential white cell count might be a useful marker for COVID-related disease severity and mortality. We conducted a systematic review and meta-analysis and investigated if the same can be predicted with on-admission NLR values and also evaluated the prognostic significance of NLR on disease outcomes in patients with COVID-19. Materials and methods: We searched PubMed, EMBASE, MEDLINE, and SCOPUS databases for published articles in peer-reviewed journals from 01 March 2020 and 01 March 2021. Meta-analysis was performed to determine the pooled standardized mean difference (SMD) for the mean values of NLR. A random-effects meta-regression was performed for the following potential confounders: age, gender, and comorbidities. Results: After study screening, systematic review included 68 studies comprising 15,818 patients in total, 2260 with severe disease and 1198 patients with mortality outcomes. The meta-analysis showed significant difference in mean NLR between severe and non-severe patients {SMD was 2.88 (95% CI: 2.32 to 3.44)} and between survivors and non survivors {SMD was 7.89 (95% CI: 3.37 to 12.42)}. Both outcomes were heterogeneous (Q = 1912.85, P < 0.0001, tau2 = 3.14, I2 = 98.35% and Q = 5898.15, p < 0.0001, tau2 = 116.65, I2 = 99.92% for severity and mortality, respectively). Meta-regression analysis showed that the association between NLR values on admission and severity in COVID-19 patients was not influenced by age (p = 0.893), cardiovascular diseases (p = 0.259), diabetes mellitus (p = 0.545), or hypertension (p = 0.104). Conclusion: On admission, NLR predicts both severity and mortality in COVID-19 patients and is not affected by age or comorbidities. Further high-quality studies are needed to confirm these findings. Results2: After study screening, systematic review included 68 studies comprising 15,818 patients in total, 2260 with severe disease and 1198 patients with mortality outcomes. A summary receiver operating characteristic (SROC) curve to determine a pooled estimate of the prognostic accuracy of NLR for severity showed that the pooled sensitivity, specificity and AUC were 80.2% (95% CI: 74.0-85.2%), 75.8% (95% CI: 71.3-79.9%), and 0.833, respectively, with the pooled diagnostic odds ratio of 13.63 (95% CI: 9.71-19.02). According to the Q-test, the true outcomes appeared to be heterogeneous for both severity and mortality (Q = 1912.85, P < 0.0001, tau2 = 3.14, I2 = 98.35% and Q = 5898.15, p < 0.0001, tau2 = 116.65, I2 = 99.92%, respectively). The same was done for NLR and mortality showed the pooled sensitivity, specificity, and diagnostic odds ratio were 78.8% (95% CI: 73.5-83.2%), 73.0% (95% CI: 68.4-77.1%), and 11.483 (95% CI: 7.814-16.875), respectively, with AUC of 0.820. Meta-regression analysis showed that the association between NLR values on admission and severity in COVID-19 patients was not influenced by age (p = 0.893), cardiovascular diseases (p = 0.259), diabetes mellitus (p = 0.545), or hypertension (p = 0.104).
ABSTRACT
OBJECTIVES: India introduced BBV152/Covaxin and AZD1222/Covishield vaccines in January 2021. We estimated the effectiveness of these vaccines against severe COVID-19 among individuals aged ≥45 years. METHODS: We did a multi-centric, hospital-based, case-control study between May and July 2021. Cases were severe COVID-19 patients, and controls were COVID-19 negative individuals from 11 hospitals. Vaccine effectiveness (VE) was estimated for complete (2 doses ≥ 14 days) and partial (1 dose ≥ 21 days) vaccination; interval between two vaccine doses and vaccination against the Delta variant. We used the random effects logistic regression model to calculate the adjusted odds ratios (aOR) with a 95% confidence interval (CI) after adjusting for relevant known confounders. RESULTS: We enrolled 1143 cases and 2541 control patients. The VE of complete vaccination was 85% (95% CI: 79-89%) with AZD1222/Covishield and 71% (95% CI: 57-81%) with BBV152/Covaxin. The VE was highest for 6-8 weeks between two doses of AZD1222/Covishield (94%, 95% CI: 86-97%) and BBV152/Covaxin (93%, 95% CI: 34-99%). The VE estimates were similar against the Delta strain and sub-lineages. CONCLUSION: BBV152/Covaxin and AZD1222/Covishield were effective against severe COVID-19 among the Indian population during the period of dominance of the highly transmissible Delta variant in the second wave of the pandemic. An escalation of two-dose coverage with COVID-19 vaccines is critical to reduce severe COVID-19 and further mitigate the pandemic in the country.