Influenza Virus Infection in Children and Adults – What’s New?

Introduction: Seasonal Influenza is a significant cause of respiratory illness among children and adults, but predominant clinical manifestations of Influenza vary among different age groups. Although the main route of Influenza virus infection is respiratory, gastrointestinal (GI) involvement has been reported, although the potential to cause direct intestinal injury remains unclear. Many studies attempted to establish risk factors for severe Influenza illness. Nonetheless, the results are controversial and this topic remains widely debated.

Aims of the Study: (a)To compare the epidemiological patterns and clinical presentation and course of the disease among children and adults; (b) To assess risk factors for a severe clinical course in each group.

Methods: This retrospective cohort study included all children (187) and adults (229) hospitalized with Influenza virus at Schneider & Beilinson Hospitals during November 2015 - April 2016.

Results: Difference in the prevalence of presenting symptoms was found between pediatric and adult populations. 21% of the children suffered from a severe clinical course compared to 29% of the adults. Children with O₂ desaturation on admission and higher CRP levels and adults with O₂ desaturation on admission and lymphopenia had a more severe clinical course.

Conclusions: Influenza is considered to be a respiratory illness, however, GI symptoms at presentation were common within both age groups. Pediatric patients showed a higher prevalence of GI symptoms at presentation, whereas the adult population had a stronger tendency to present with respiratory symptoms and myalgia.