Objective: To probe into the effects of neutrophil-lymphocyte ratio on efficacy evaluation and prognosis prediction value of children with influenza B virus infection. Methods: Clinical data of 304 children with influenza B virus infection admitted into our hospital from Oct. 2016 to Apr. 2018 were retrospectively analyzed. The related factors that may lead to poor prognosis were counted

and the differences of the possible influencing factors between the good prognosis group and the poor prognosis group were compared

and the related factors were determined by Logistic regression analysis. NLR before treatment were collected

NLR were compared among two groups of children

the effective group

ineffective group

good prognosis group and poor prognosis group. Receiver operating characteristic (ROC) curve was drawn to analyze the efficacy and prognosis prediction of NLR in children with influenza B virus infection of two age groups. Results: There were no significant difference in the proportion of gender

obesity

course of disease

influenza vaccination history within one year

acute respiratory distress

hepatic insufficiency

cardiac insufficiency

hemoptysis and vomiting between the good prognosis group and the poor prognosis group (P>0.05)

while the proportion of children aged <6 years

with severe hypoxemia

bacterial infection

renal insufficiency

immune system diseases

NLR >3.25 in the good prognosis group were higher than those in the poor prognosis group (P<0.05)

Logistic regression analysis proved that the above indicators were risk factors for poor prognosis. The effective rates of group A and group B were respectively 77.66% and 82.76%

and NLR of the effective group was lower than that of the ineffective group (P<0.05). The incidences of poor prognosis of group A and B were respectively 11.70% and 2.59%

and NLR in the good prognosis group were lower than those in the poor prognosis group (P<0.05). The best cut-off points for NLR to evaluate the efficacy of group A

B and C for children with influenza B virus infection were 1.58 and 2.35

with accuracy of 95.21% and 93.97%

and AUC of 0.896 and 0.902. The best cut-off points of NLR for predicting the prognosis of children with influenza B virus infection in group A and B were 2.85 and 6.35

with accuracy of 91.49% and 96.55%

and AUC of 0.853 and 0.913. Conclusion: NLR >3.25 is a risk factor for poor prognosis of children with influenza B virus infection

and NLR has higher predictive value in efficacy and prognosis prediction of children with influenza B virus infection in different age groups.