A Model to Improve the Screening and Linkage to Care of HDV Infection in Migrant Living in Southern Italy Taking Advantage of HDV Reflex Testing: MIGrant Reflex Test HDV (MIGRED) Project

Hepatitis D virus (HDV) infection, which occurs only in subjects with hepatitis B infection, increases the risk of hepatocellular carcinoma (HCC), decompensated cirrhosis, and mortality compared to hepatitis B virus (HBV) mono-infection. Therefore, estimates the prevalence of HDV infection and disease burden are essential to investigate models to find coinfected individuals more effectively and in an efficient way. Diagnosis of HDV allows to reduce the risk of disease progression and prevent HDV transmission, allows to intervene with antiviral treatment and allows to follow-up HDV positive subjects with ultrasound for HCC surveillance [1-4]. The data on the prevalence of HDV worldwide is unclear, with an estimated prevalence of anti-Delta-positivity in HBsAg positive patients of 4.5%-13% and an estimated number of anti-Delta-subjects of 8,2-60 million [5-6]. These variable estimates may be due in part to the fact that not all HBsAg-positive subjects were screened for anti-Delta. All the strategies for the improvement of the rate of screening of HBsAg-positive-subjects may improve the knowledge on the prevalence of HDV worldwide, especially in the high endemic populations. Recently, one of the strategies that has shown good results in the identification of HDV infection is the use of anti HDV reflex testing [4]. However, HDV is highly endemic in several African countries and in some countries in South America, the Middle East, central and northern Asia, and Eastern Europe [7]. A systematic review of the prevalence of HDV infection in HBsAgpositive populations in sub Saharan Africa showed a pooled seroprevalence in HBsAg-positive general populations and in patients with liver disease of 7.33% and 9.57%, respectively in western Africa, of 25.6% and 37.8% in central Africa, and of 0.05% in the general populations of eastern and southern Africa [8]. In Italy the prevalence of HDV infection in HBsAg-positive subjects ranges from 9.7 to 12%, with evidence of an increasing prevalence of HDV infection in the immigrant population in recent years [9-15]. Probably, this happened because for its geographical position in the center of the Mediterranean Sea, Italy has been greatly involved in immigration from Africa, in particular from sub-Saharan Africa, and also from Asia and Eastern Europe; for example from January 2023 until September 2023 in Italy are arrived about 128,000 migrants and most of them coming from Sub-Saharan Africa and East Europe, prevalence (Situation Mediterranean Situation (unhcr.org), all areas with high HDV prevalence, The majority of these migrants arrived, as first site, in Southern Italy, Sicily, Apulia, Calabria and Campania. However, few data have been published so far on the prevalence of HDV infection in immigrant populations in Western countries and in Italy and even poorer is the information on the virological and clinical aspects of HDV infection in this population.

Our research group performed a valid strategy to improve the detection for viral hepatitis and the link to care in migrants, contributing to the improvement of knowledge on clinical and virological futures of viral hepatitis in this population difficult to reach and to manage [1-3]. Our hypothesis is that the extension of our model in other three large university clinical centers operating in southern Italy and the use of the HDV reflex testing for HBsAg-positive individuals will allow to implement the knowledge on the HDV prevalence in migrants living in southern Italy and coming from endemic areas for HDV. Precisely, the investigators will involve the Department of Infectious Diseases of the University of Bari, that of the University of Catanzaro and that of the University of Palermo with expertise in the management of infectious diseases in migrant and with which the investigators previously collaborated in other setting.The investigators performed a retrospective and prospective multicenter project lasting 18 months involving the 4 largest University clinical Centers for Infectious Diseases (ID) in southern Italy:

Departments of ID of the University of Napoli L.Vanvitelli (project coordinator), of the University of Bari, of the University of Catanzaro and of the University Palermo.

At this time they are not involved in any other projects involving screening and linkage to care of HDV infection.

Each of these tertiary center is associated to 1st level clinical centers, that are centers of general practice clinics attended mainly by migrants for low back pain, headache, itching, cough, hypertension and allergy symptoms. These first-level centers are linked with the Italian humanitarian organizations which welcome needy migrants. The organization of these clinics involves the presence of a physhycian expert in the management of infectious diseases in migrants, a nurse and a cultural mediator. This last figure is fundamental in explaining the epidemiological, clinical and collective health reasons that make it necessary to screen for hepatitis viruses which are endemic in their areas of origin.