"Hepatitis E virus seroprevalence in immunosuppressed patients in Belgium : a prospective study."

Philippart, Marie [UCL] Peeters, Michaël [UCL] Piessevaux, Hubert [UCL] Badii, Maria Chiara [UCL] Bailly Sarah [UCL] Poire, Xavier [UCL] Kanaan, Nada [UCL] Devresse, Arnaud [UCL] Kabamba-Mukadi, Benoît [UCL] Dahlqvist, Géraldine [UCL]

Background and aims: Hepatitis E virus (HEV) is the commonest cause of acute viral hepatitis in Western countries. In immunocom- promised patients, chronic HEV have been described, leading in certain cases to cirrhosis, decompensation and death or liver transplantation. The aim of the study is to determine the prevalence of HEV infections in the immunosuppressed population followed in a single tertiary center in Belgium. Method: From May 2022 to April 2023, we are prospectively screening for HEV (IgG, IgM and PCR) all patients transplanted from a solid organ (SOT) as well as patients suffering from a lymphoma or followed in the hematology department for a bone marrow transplantation under immunosuppression from at least three months. We compared the data from our immunosuppressed patients to the data collected from national serum banks in Belgium in 2014 by Ho et al., representing the general seroprevalence in Belgian population. Chi2 test or Fisher exact test were performed to compare the groups. Results: We present here an intermediate analysis after 8 months of screening. Among 570 patients, 240 were followed for a kidney transplantation (KT), 139 for a heart transplantation (HT), 163 for a liver transplantation (LT), and 55 for haematological disease (HD). The median age was 61. The sex ratio F/M was 1/2. The mean IgG HEV seroprevalence was 9.29% in our population, 8.1% in KT, 13% in HT, 14.8% in LT and 0% in HD. A positive HEV PCR was found in 6 patients, 5 in the KT group and one followed for HD and genotype 3c was identified in all of them. There is a significative difference between the HEV IgG seroprevalence in Belgian population in 2014 (5,8%) and our population ( p = 0.001). In subgroup analysis, there is a significa- tive difference between the Belgian population and the patients followed for LT (p=0.0006) and HT (p=0.0114). There is also a significative difference between the different SOT groups and the patients followed for hematological diseases (LT vs HD: p = 0.0026; HT vs HD: p=0.0068; KT vs HD: p=0.03). Conclusion: The seroprevalence between our group of immunosup- pressed patients and the Belgian population is significantly higher. Subgroup analysis showed a significantly higher seroprevalence in HT and LT patients but does not translate into an actual chronic infection rate. KT is a risk factor for the occurrence of chronic HEV compared to other SOT groups. The seroprevalence is however not significantly different in this group compared to the general population. More data are awaiting to draw conclusions on the importance of systematic screening in these immunosuppressed populations.