This study monitored viral load in asymptomatic blood donors, unveiling insights into the progression of HEV infections, vital for public health strategies.
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In Germany, a study examined samples from 32 asymptomatic blood donors who tested positive for HEV RNA. Through close monitoring of viral load and seroconversion at approximately 4-day intervals, researchers gained insights into the dynamics of asymptomatic HEV infections.
Findings revealed a typical HEV infection initiated with PCR-detectable viremia around day 36, reaching a maximum viral load of 2.0 × 104 IU/mL. Viremia doubled every 2.4 days and exhibited a half-life of 1.6 days. HEV IgM levels began rising around day 33, peaking on day 36, while IgG levels commenced rising around day 32 and peaked on day 53. Notably, HEV IgG titers remained stable, but IgM titers became undetectable in 40% of donors.
“Because our studied data represent asymptomatic infected persons retrospectively identified from retained samples stored over years, closely meshed follow-up samples are available for viral load, and those data provide a unique opportunity to gain understanding of kinetics in asymptomatic blood donors,” according to the investigators. “Blood donations from asymptomatic donors pose a risk for development of transfusion-transmitted severe and chronic HEV in immunosuppressed patients and recipients of solid organ transplants.”
Understanding the dynamics of HEV viremia holds significance for assessing the risk of transfusion-transmitted HEV. This study sheds light on the temporal aspects of HEV infection progression in asymptomatic individuals, providing valuable insights for public health management strategies.
“A comparison of data from asymptomatic persons with viremia characteristics of patients after solid organ transplantation published by Pas et al. resulted in a striking discrepancy,” according to the investigators. “First, the discrepancy is reflected in the fact that the median time between detection of HEV RNA and detection of HEV IgG was 124 days, whereas in our study that period was only 33 days. Second, chronic HEV developed in 11 of 12 organ recipients with a median duration of 16 months chronic HEV developed in none (>3 months viremia) with a median infection period of 36 days.”
The study acknowledges limitations, highlighting the absence of comparative data, particularly data from symptomatic patients, which limits the ability to fully contextualize the findings regarding the doubling time and half-life of HEV viral load during viremia. While the study compares HEV kinetics with those of other viral infections like HAV, HCV, and HBV, it recognizes that HEV kinetics may differ from these viruses, suggesting that the comparison may not entirely capture the nuances of HEV infection dynamics. The study notes variability in the maximum HEV viral load among donors and indicates that the detected maximum viral load may be lower like other viral infections like HBV. This variability could affect the generalizability of the findings and the interpretation of HEV infection kinetics.
These limitations underscore the need for further research to understand the dynamics of HEV infection and its implications for public health management. Comparison with other viral liver infections highlights differences, emphasizing the typically less severe nature of HEV infection in healthy individuals and the impact of factors like immunosuppression.
Reference
Plumers R, Dreier J, Knabbe C, et. al. Kinetics of Hepatitis E Virus Infections in Asymptomatic Persons. Emerg Infect Dis. 2024;30(5):934-940. doi:10.3201/eid3005.231764
