Discussion
fever
VIRUS, RECURRENCE, RECURRENCE, INFLUENZA A(H3N2), COMPLICATIONS, INFLUENZA
Anti-influenza treatment is important for children, particularly those < 5 years or those with at risk conditions who are at a higher risk of developing complications than older healthy children and adults [In this study, median TTIA was similar among the age groups (< 6 years: 43.2 hours; ≥6 to < 12 years: 45.4 hours) even though a temporary virus titer increase was observed mainly in younger children. Because our studies did not contain a control group, to estimate baloxavir effectiveness we compared our findings with previous NAI studies in children. Most patients in our studies were infected with influenza A(H3N2), and a comparison of patients aged < 6 years with influenza A(H3N2) with those aged 3–9 years treated with laninamivir or oseltamivir suggests baloxavir’s effectiveness in reducing TTIA (median: 38.9 hours with baloxavir vs 88.6 hours with laninamivir and 44.3 hours with oseltamivir) [Recurrence of fever is observed in > 25% of children aged < 12 years in the natural course of influenza [Treatment-emergent PA/I38X-substituted influenza viruses appear to be more common in baloxavir-treated pediatric patients aged < 12 years, occurring at rates of 19.2–23.4%, compared with adult and adolescent influenza patients (2.2–9.7%) [The pooling of two study populations enabled us to analyze safety, clinical, and virologic outcomes by age group and influenza virus type/subtype in baloxavir-treated pediatric patients. The study was also enhanced by the range of parameters that were assessed (e.g., TTIA, TTRF, recurrence of symptoms and fever, virus titer, and emergence of PA/I38X-substituted virus), allowing for some association between the clinical and virologic outcomes to be made.Limitations of this study include the post hoc nature of this analysis, the lack of a control group, and the imbalance in patients with influenza A(H1N1)pdm09 and B across the age groups. This is likely due to the fact that the two studies were conducted in different influenza seasons and the granule study contributed most of the younger patients.Another limitation is the detection of co-infection. We conducted a reverse transcription PCR against 20 respiratory microorganisms from nasal/throat swab samples to detect co-infection (Additional file 