Aims To examine whether there is link between influenza strains in children and length of hospital stay (LOS), transfer to ICU, mortality, secondary bacterial infection (SBI) or peripheral blood tests.

Methods We studied 141 patients attended our hospital between November 2017 and March 2018.

Results Influenza A was reported in 80 (56.7%), influenza B in 60 (42.6%) and both strains in one. Mean (SD) age was 5.12 (4.30) years. Statistically, patients were divided into two groups (influenza A and influenza B). Admission to paediatric ward was required in 91 patients (64.54%), of whom two required transfer to ICU, with no mortality. Mean (SD) LOS was 2.33 (1.92) days, with no link between LOS and influenza viral strains (p value 0.35).

Of 141 patients, 111 underwent blood tests. The majority had normal total WBC [72 patients (64.9%)] and neutrophil values [80 (72.1%)], normal lymphocyte [61 patients (55.0%)] and monocyte values [64 (57.7%)]. However, total WBC, neutrophil, lymphocyte and monocyte values were elevated in 9 (8.1%), 19 (17.1%), two (1.8%) and 47 (42.3%) patients, respectively. Total WBC, neutrophil, lymphocyte or monocyte values did not differ between the groups (p value 0.48, 0.52, 0.71 and 0.38, respectively).

In terms of predicting influenza strains, neutrophil lymphocyte ratio (NLR) and monocyte lymphocyte ratio (MLR) have low sensitivity, with area under the ROC curve 0.42 and 0.53, respectively. Mean (SD) C-reactive protein (CRP) value was 14.45 (10.12) mg/L, with no difference between the groups (p value 0.52). No organisms were detected in 79 patients who underwent peripheral blood culture.

Conclusion Influenza can occur with normal WBC and CRP values. NLR or MLR has no role in predicting influenza serotypes. In this group of patients, the vast majority did not require transfer to ICU. Moreover, there is no link between influenza viral strains and LOS, mortality or SBI.