When compared to other age groups, influenza is associated with a higher risk of serious disease and hospitalisation among children under the age of five. Influenza vaccine minimises the chance of infection and may lessen the severity of the condition. Recent European research suggests that employing an unique criterion to define influenza sickness as mild versus moderate-to-severe (M-S) may be clinically significant. The study looked back to see if our M-S categorization accurately described the severity of influenza in a group of youngsters in the United States. They included children aged 18 at Kaiser Permanente Northern California who had PCR-confirmed influenza.

Children were classified as M-S if they experienced at least one of the following symptoms: fever >39°C, acute otitis media, lower respiratory tract infection (LRTI), or extrapulmonary consequences; otherwise, they were classed as moderate. Almost half of the 1,105 youngsters who tested positive for influenza were classed as M-S. Children aged 6–35 months had the largest proportion of M-S illness, primarily due to LRTI and fever. Children with M-S illness who were 6 months old had a 1.6 to 2.8 times higher likelihood of visiting the emergency room or having any follow-up outpatient visits. An influenza classification system may help identify between youngsters who have clinically serious sickness.

Reference: https://www.tandfonline.com/doi/full/10.1080/21645515.2019.1706412