Long-term impact of suboptimal rotavirus vaccines on acute gastroenteritis in hospitalized children in Northern Taiwan

Background/Purpose: Rotavirus vaccines were launched in Taiwan since early 2006. Our study was aimed to figure out long-term extended molecular epidemiology in acute gastroenteritis (AGE) in hospitalized young children after rotavirus vaccination in Taiwan. Methods: During the 10-year period from January 2007 to December 2016, fecal samples from children under 5 years old with AGE hospitalized in Chang Gung Children's Hospital (CGCH) were examined for enteric pathogens and they were divided into two time intervals: early post-vaccine (Jan. 2007 to Dec. 2011; EPV) and late post-vaccine (Jan. 2012 to Dec. 2016; LPV). Results: In total, 837 patients with AGE were enrolled with complete study. In the EPV period, 106 (26.7%) rotavirus and 65 (16.4%) norovirus infections were identified as major pathogens. In the LPV period, 79 (17.9%) rotavirus and 98 (22.2%) norovirus infections were diagnosed. Statistical analyses showed a significantly decreased prevalence of rotavirus infection (P = 0.002) and a significantly increased prevalence of norovirus (P = 0.034) and enteric bacterial infections (P < 0.001). A substantial decrease of rotavirus G1 (P = 0.079) in the LPV period and norovirus GII.4 prevailed through the decade. Conclusion: In Taiwan, under a suboptimal rotavirus vaccination policy, there was a marked decrease in the rate of rotavirus AGE of hospitalized young children. Significantly increased norovirus infection has replaced rotavirus as the leading cause. Expansion of rotavirus vaccine coverage, development of a norovirus prevention strategy, and sustained bacterial infection control are important for AGE containment in children in Taiwan.