Influenza ; Age difference ; Children ; Clinical features ; Vaccination
Abstract
Purpose: Influenza vaccination is mandatorily recommended for children from 6 months old to 59 months old. I did this study to know the clinical differences of childhood influenza before and after 5 years old. Methods: I collected clinical informations of influenza patients who had been diagnosed and admitted at the Department of Pediatrics, Yogin Severance Hospital from January 2014 to April 2016. Influenza infection was decided by rapid antigen test from nasopharyngeal swab. They were divided for group A (60 months old and over) and group B (younger than 60 months old). Their epidemiological and clinical features were investigated and compared with each other. Results: There were 51 cases for group A and 59 cases for group B. Both groups showed peak incidence on February. Their male to female ratio were not significantly different between them (22:29 for group A vs. 29:30 for group B). Their clinical manifestations such as frequency of fever, cough, rhinorrhea, sputum, abdominal pain, vomiting , diarrhea and fever duration for pre- and after admission did not showed any significant difference. Nausea were found on 8 cases (15.7%) in group A and none in group B ( P =0.002). Headache was shown on 6 cases (11.8%) in group A and none in group B ( P =0.008). Lower respiratory tract involvements were noticed on 29 cases (56.9%) in group A and 39 cases (66.1%) in group B. Their admission durations were comparable with each other (3.2±1.1 days for group A and 3.3±1.3 days for group B). Regarding to laboratory findings, leukopenia (35.3% for group A vs. 15.3% for group B; P =0.015) and lymphocytopenia (66.7% for group A vs. 25.4% for group B; P <0.001) were more frequent in group A than in group B. But group B had more cases with decreased total CO2 content (76.5% for group A vs. 93.2% for group B; P =0.016) and elevated serum aspartate aminotransferase(41.2% for group A vs. 72.9% for group B; P <0.001). Conclusion: The cases of 5 years old and over were almost half of all admitted childhood influenza children, and the overall clinical features and prognosis are comparable between the two groups. These findings offer support for new guideline to expand the age limitation of mandatory vaccination.