The cause is the bacterium Salmonella typhi, also known as Salmonella enterica serotype typhi, growing in the intestines and blood. China is considered as one of the Asian countries where typhoid fever is endemic. As a gastrointestinal infection that is both waterborne and food-borne, typhoid fever poses a problem in developing countries, such as China, that do not have optimal safe water supply, sanitation conditions, and food hygiene. However, the prevalence of multi-resistant strains of S. typhi has increased in China; "by 1989, 80 percent of S. typhi isolates in Shanghai were multi-resistant". The incidence of typhoid ranged from 15.3 cases per 100 000 person-years among those aged 5–60 years in China.
A typhoid vaccine can prevent about 50% to 70% of cases. The vaccine may be effective for up to seven years. It is recommended for those at high risk or people traveling to areas where the disease is common. Other efforts to prevent the disease include providing clean drinking water, better sanitation, and better handwashing. Researches focusing on Safety and Immunogenicity of a Quadrivalent Meningococcal Conjugate Vaccine and Commonly Administered Vaccines after Co-administration, Molecular subtyping of Salmonella enterica serovar Typhi isolates.