Abstract
Abstract Hepatitis A is caused by hepatitis A virus and occurs worldwide. Estimating the transmissibility, which is usually characterized by the so-called basic reproductive number R0, the mean number of secondary infectious cases generated by one primary infectious case introduced into a totally susceptible population, provides crucial information for the effort required to eliminate infection. Hepatitis A virus is usually transmitted indirectly through contaminated food and environment. An outbreak from March to June 2011 was reported to occur at an elementary school in China and it was evidenced that the outbreak is due to direct transmission between school children. Based on the data of symptom onset date and social contact network, in this study we estimate the serial interval (the gap in symptom onset between an infectors and its infector) and use different statistical methods to estimate R0.To take into account the fact that many HAV infections in children are asymptomatic, a transmission dynamics model is proposed to estimate R0. Our results suggest a serial interval of mean =23.9 days and standard deviation =20.9 days. The different statistical methods suggest that R0 in the 2011 outbreak at the elementary school in China ranges from 1.9 to 2.5, which overlap with the results from the epidemic model. Our estimates are in agreement with the estimate in England but higher than that in the United States.