Detection of norovirus and rotavirus among inpatients with acute gastroenteritis in a medical center in northern Taiwan, 2013–2018

Background: Norovirus (NoV) and rotavirus (RV) are among the most common causes of acute gastroenteritis (AGE) of all ages worldwide. There have been scanty reports of the epidemiology data of NoV AGE from clinical virologic laboratory. Methods: All stool specimens sent to the virologic laboratory in a medical center in Taiwan for detection of both NoV (by reverse transcription-polymerase chain reaction) and RV (by enzyme immunoassay) from 2013 to 2018 were included for analysis. Results: A total of 15,991 specimens, annually ranging from 2430 in 2017–2915 in 2013, were included. 48.0% and 73.1% of the specimens were obtained from children aged < two years and < five years, respectively. Overall, the positive rate was 13.8% for NoV and 13.2% for RV. Yearly positive rate of NoV ranged from 11.1% to 17.4%. The positive rate in 2018 (17.4%) was significantly higher than that in other study years. NoV positive rate was higher in cold season from January (28.3%), February (23.1%), to March (17.9%) while lower in warm seasons from May to September (less than 10%). By age, NoV positive rate was highest in aged 1–4 years (17.3%) and decreased with age. The yearly positive rate of RV showed a significantly steady decrease from 15.6% in 2013 to 9.1% in 2018 (p < 0.001 by trend analysis). Conclusions: In northern Taiwan, NoV, surpassing RV, accounted for one of seven inpatients with AGE during 2013–2018. NoV activity peaked in cold season and children aged <5 years were more commonly encountered.