Duration of viraemia in Chinese acute sporadic hepatitis E.

Acute sporadic hepatitis E (ASHE) cases induced by hepatitis E virus genotype 4 (HEV-4) are increasing in China. Our study aimed to estimate the duration of HEV-4 viraemia in Chinese ASHE. A total of 619 serum specimens from 499 ASHE patients were examined for the presence of HEV RNA. The association between viraemia detection and serum sampling time was compared between subtypes. The cumulative probability of HEV viraemia detection was determined using Kaplan-Meier survival analysis, and the viraemia duration was estimated. A total of 42.7 % of serum specimens were positive for HEV RNA and all the isolated strains were identified as genotype 4 and subsequently assigned to five subtypes. Among the patients infected with subtypes 4d and 4i, the time interval from the initiation of clinical symptoms to serum specimen sampling was shorter than that among the patients with subtypes 4a, 4b and 4h. Kaplan-Meier analysis was conducted with 101 sequential specimens as well as with both 101 sequential specimens and 236 single negative specimens. The cumulative probability of HEV-4 viraemia detection was estimated to decline quickly to approximately 10 % within 32 days after the initiation of clinical symptoms and then to decline very slowly to 5 % by the 41st day and to zero by the 131st day. The majority of ASHE cases maintain detectable HEV-4 viraemia within one month after onset, whereas a small portion of cases maintain long-term viraemia and may act as a reservoir for further transmission.