Epidemiological Study of Influenza A, Influenza B, Enterovirus 71, and Coxsackievirus A16 Among Children in the Central Region of Zhejiang Province, China.

Influenza A virus (IAV), influenza B virus (IBV), enterovirus 71 (EV71), and coxsackievirus A16 (CVA16) are common pathogens for viral infection in children. In order to investigate the epidemiology of these four viral infections in the central region of Zhejiang province, China, 10,638 respiratory secretion samples previously tested for IAV and IBV, and 6427 whole blood samples previously tested for EV71 and CVA16 detection were analyzed retrospectively. The present data shows that viral infections with these four viruses featured with distinct seasonal patterns. Both IAV and IBV infections more frequently occurred in winter, while infections with the two enteroviruses peaked in summer with high positive rates in other months. The most susceptible ages for IAV, IBV, EV71, and CVA16 were 2-7 years old, 4-6 years old, 1-3 years old, and 1-2 years old, respectively. It was recommended that children in the central region of Zhejiang Province should be vaccinated for influenza by the end of October every year, especially between the ages of 2 and 7 years old and children in age from 1 to 3 years old should be paid more attention all year round for EV71 and CVA16 infection. Moreover, the female gender appeared to be a risk factor only for IBV infection, while CVA16 inflicted more infection in young children. This study revealed that season, age, and gender should be taken into consideration when devising vaccination schedules for children in the central region of Zhejiang.