Migratory flow and hepatitis delta infection in Italy: A new challenge at the beginning of the third millennium

Abstract

In Italy, HDV infection endemicity has greatly decreased overtime. Migratory flow may change this scenario as migrants often come from high HDV endemicity areas. Here, we studied characteristics of HDV infection in Italy, particularly addressed to the birth area of subjects. Chronic HBsAg carriers consecutively referring to 9 units in Italy prospectively enrolled for a six‐month period in 2019 were tested for anti‐HDV by ELISA. Multiple logistic regression analysis was performed to identify anti‐HDV positivity independent predictors. A total of 894 HBsAg‐positive subjects were enrolled. Of them, 786 (87.9%) were tested for anti‐HDV. Anti‐HDV overall prevalence was 9.9% (6.4% in Italian natives and 26.4% in non‐natives; P < .001). HDV‐RNA was checked in 63 (80.8%) of the 78 anti–HDV+ subjects, and 49 (77.8%) tested positive. Compared to non‐natives, Italians were more likely males (male/female 1.6 vs 0.6; P < .05) and older (median age 57 years vs 46 years; P < .05). Multivariate analysis showed that non‐natives (OR = 6.02; CI 95% = 3.06‐11.84) and cirrhosis (OR 9.6; CI 95% = 5.39‐17.30) were independently associated with anti‐HDV positivity. A remarkable changing pattern in some characteristics of anti–HDV‐positive subjects was observed over 1987‐2019: a decreasing male/female ratio, an increasing mean age and proportion of cirrhotic subjects. Anti‐HDV prevalence decreased from 7.4% to 6.4% among Italians, increasing from 12.2% to 26.4% among non‐natives during 2001‐2019. Hence, HDV infection in Italians is further decreasing and mostly affects old people and subjects with advanced disease reflecting a survival effect. Conversely, non‐natives are sixfold more likely anti–HDV‐positive with an increasing trend. Migratory flow may be a new challenge for HDV infection at the beginning of the third millennium.

The changing context of hepatitis D

“…28 In Europe, the demise of HDV in domestic populations has been offset by new infections introduced by immigrants from areas where HDV remains endemic. 29 The relative proportion of HDV-infected migrants is increasing compared to HDV-infected native populations 30 ; migratory flows have interrupted the decline in infections, whose prevalence in HBsAg carriers stabilised in the last decade at 8-10% in Germany, Italy, Spain and France. 31 The pattern of decreasing domestic and increasing migrant HDV infections is being observed in all high-income countries.…”

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

“…In Italy, several studies have shown a decreasing prevalence of Delta infection among chronic HBsAg carriers from 23.4% in 1987 8 to 8.3% in 1997 9 ; thereafter it remained stable around 10.0% during the first two decades of the third millennium 10–13 . In the last survey, 13 HDV prevalence among Italians further decreased to 6.4%; instead it was 26.4% among foreigners, outlining that migration flow counterbalances the residual cohort of long‐term native infections acquired during the 1970s and 1980s.…”

Hepatitis D virus infection in a large cohort of immigrants in southern Italy: a multicenter, prospective study

“…In the same year, another study conducted on 488 HBsAg-positive subjects [ 37 ] including 107 immigrants, found no difference in the HDV prevalence between Italian and immigrant subjects (7% and 7.3%, respectively). Instead, more recently, evaluating HDV prevalence in 786 HBsAg-positive subjects in 9 liver units prospectively enrolled for a 6-month period in 2019, the anti-HDV overall prevalence was 9.9%, 6.4% in Italian natives and 26.4% in non-natives [ 38 ].…”