The Seasonal Changes of Influenza Virus and Rotavirus in Children

Lee, Sang Min; Lee, So Yeon; Kim, Young Ho; Lee, Kyu Man; Kim, Kwang Nam

Abstract

PURPOSE
The seasonality of influenza virus and rotavirus are well recognized in winter and so viral surveillance and laboratory-based diagnostics are important to guide the timing of prophylaxis and other interventions. Yet the seasonality of these two viruses are changing in Korea. We evaluated the prevalence and clinical features of influenza virus and rotavirus.
METHODS
From September 2001 to August 2005, nasopharyngeal aspirates were cultured from the hospitalized patients with lower respiratory infections and the stools from hospitalized patients with gastroenteritis were tested for rotavirus. We retrospectively analysed the medical records.
RESULTS
During the study period, respiratory virus was isolated in 578 (18.5%) out of 3,121 patients. Influenza virus was isolated in 143 cases. The seasonal distribution of influenza infection was from December to June of the next year. The ratio of males to females was 1.3:1 and the median age was 17 months. The most common diagnosis of influenza infection was bronchiolitis. Fever and cough were present in 94.4% and 83.9% of the patients, respectively. During the same period, 3,850 patients were admitted for gastroenteritis and 1,047 (27%) patients were positive for rotavirus. Rotavirus was prevailed from December to June of the next year and it presented in year-round. The ratio of males to females was 1.1:1 and the median age was 16 months. Diarrhea and vomiting were the most common symptoms.
CONCLUSION
The recent peak prevalence of influenza virus and rotavirus in Korea was in winter and the late spring, respectively. So we need to expand surveillance and carefully consider the correct period to vaccinate people.