The Burden of Influenza Virus Infection among Children under 12 Years Old in Tropical Countries

Every year influenza epidemic causes about 3 – 5 million severe respiratory infections and 250,000 to 500,000 deaths worldwide. Among them about 28,000 – 111,500 (11 – 22%) children under 5 years old die because of influenza-related acute lower respiratory tract infections. This review aims to explore the burden, risk factors and seasonality related to influenza virus infection among children under 5 years old in tropical countries. From 1st to 31st December 2020 literature search was done on PubMed and ScienceDirect databases using ‘influenza’ and other keywords such as paediatric, children, neurology complication and breastfeeding for articles published in the English language. About 10% of hospitalization with respiratory infections in children <18 years old are related to influenza. It is reported that about 11% – 26% of febrile illnesses among outpatients and 6 –14% of hospitalized patients with pneumonia were due to influenza virus. Global paediatric mortality estimates that death caused by influenza is highest among 1 – 12 months old children which is about 2.8% of all deaths. In Malaysia, there are no seasonal variations of influenza and the prevalence is higher during the middle of the year. Risk factors include male, age <12 months old and presented with seizure. Breastfeeding and vaccination for pregnant mothers can be beneficial for infants up to 6 months old. Influenza among the paediatric group is a significant health burden even in healthy children and are likely to be underdiagnosed. Vaccination can also be focused on pregnant mothers and children less than 12 years old.