Clinical and virological characteristics associated with severe acute hepatitis B
Abstract
To identify early predictors of a severe or fulminant course in patients with acute viral hepatitis B (AVH-B). One hundred and thirty-eight patients with symptomatic acute hepatitis B observed from 1999 to 2012 were enrolled. For each patient, the demographics, risk factors for the acquisition of hepatitis B virus (HBV) infection, clinical, biochemical and virological data (HBV DNA, HBV DNA sequences) were recorded and analysed. The HBV mutants in the polymerase region were sought in 110 (87%) patients by direct sequencing, and the rtM204V/I mutations also by an allele-specific PCR. AVH-B was severe in 13 (9.4%) of the 138 patients enrolled, fulminant in 6 (4.3%) and with a normal clinical course in 119. The 19 patients with severe or fulminant AVH-B more frequently than the 119 with a normal course stated intravenous drug use (63.2% versus 36.1%, p 0.04) and were HBV-DNA negative (31.6% versus 11.8%, p 0.03) and anti-hepatitis C virus (HCV) positive (57.9% versus 19.3%, p 0.0008); the prevalences of different HBV genotypes and of the rtM204V/I mutant were similar in these three forms of AVH-B. A multivariate logistic regression analysis identified a pre-existing HCV chronic infection as the only factor independently associated with a severe or fulminant clinical course of AVH-B (OR 4.89, 95% CI 1.5–15.94, p 0.01). A pre-existing HCV chronic infection was identified as the only factor independently associated with a severe clinical presentation of acute hepatitis B, an association most probably due to the combination of the liver lesions caused by acute hepatitis B and the pre-existing histological abnormalities related to HCV chronic infection.
Introduction
The clinical presentation associated with the hepatitis B virus (HBV) acute infection varies according to the grade of reactivity of cell-mediated immunity: low or absent in newborn babies and infants, who frequently present an asymptomatic infection, moderate in children aged under 12 years, who frequently develop an asymptomatic or mild acute hepatitis, normal or high in children aged over 12 years and in adults, most of whom show symptomatic acute viral hepatitis B (AVH-B) 1, 2. An over-reaction of the immune system leads to fulminant hepatitis in nearly 1% of the cases 3, a clinical form of AVH-B with a very high fatality rate that requires liver transplantation in the majority of cases. Progression to chronicity decreases with the increase in age, occurring in nearly 90% of newborn babies, in 10–40% of children, in nearly 5% of young adults and in 2% of the older population 1.
The improvement in socio-economic and hygiene conditions, the implementation of mass immunization programmes and the routine screening of blood donors have led to a reduction in the incidence of AVH-B in the younger population in western countries 4. In these areas AVH-B infection is most frequently acquired by non-vaccinated adults through promiscuous unsafe sexual intercourse or injection drug use 5, associated with a high probability of a symptomatic clinical presentation that is sometimes severe and seldom life threatening 6.
Old studies identified being female or being a young adult as risk factors for a more severe clinical presentation 1, 7. More recent investigations identified some virological factors influencing the clinical presentation and course of AVH-B 8-11: HBV genotype D, described in the USA with a rate in patients with a fulminant course that is double the rate in those with a normal course 8; the subgenotype B1/Bj, frequently identified in the fulminant form in Japan and the G1896A mutation and serum HBV DNA >5.23 log copies/mL, identified as independently associated with a fulminant course 10; and the rtM204V/I variant found to be associated with severe acute hepatitis B in Italy 11. In addition, HBV genotype A was found to be independently associated with a prolonged course of the illness and with progression to chronicity 12, 13. Also certain lifestyle factors (alcohol intake, drug use) and environmental factors (concomitant hepatitis C virus infection) have been associated with a more severe clinical course of AVH-B 14, 15. Nevertheless, factors inducing a severe clinical presentation and an unfavourable outcome are not fully understood and further investigation is needed.
The present study was performed on 138 consecutive patients with AVH-B and the aim was to identify early predictors of a severe or fulminant course.
Patients and Methods
Patients
One hundred and thirty-eight consecutive patients with symptomatic AVH-B were enrolled at one of the two participating Units of Infectious Diseases from September 1999 to December 2012. These two Units, one in Naples and one in Caserta, had been using the same clinical and laboratory approach for years and had cooperated in several clinical investigations 16-18.
All patients had detectable serum hepatitis B surface antigen (HBsAg) and IgM to hepatitis B core antigen (anti-HBc IgM), showed increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum values of at least ten times the upper normal level, and lacked antibodies to hepatitis Δ virus (anti-HDV) and to anti-human immunodeficiency virus (HIV). Two patients with AVH-B observed in the same period, one with HBV/HDV co-infection and one with HBV/HIV co-infection, were not included in the present study. No patient had been vaccinated against HBV. Ninety-two (66.7%) patients had tested HBsAg negative in a screening performed 3–12 months before the onset of symptoms.
A questionnaire recording information on the demographics and risk factors for acquiring HBV infection was completed by each patient. A daily alcohol intake exceeding 30 g/day for women and 40 g/day for men in the last 6 months or more was defined as alcohol abuse; the patient's statements regarding intravenous drug addiction and alcohol abuse were corroborated by the patient's family and by serum/urine tests in uncertain cases.
No patient received nucleos(t)ide analogue treatment because at the time the study was performed these drugs were licensed only for chronic hepatitis B in Italy.
Six patients with porto-systemic encephalopathy associated with a rapid progressive reduction in prothrombin activity to below 35% were considered to have developed fulminant hepatitis 11, 15. Thirteen patients showed a severe clinical presentation (severe hepatitis) characterized by the development of ascites or by a progressive reduction in prothrombin activity to below 35%, in the absence of porto-systemic encephalopathy.
All procedures used were in accordance with the international guidelines and with the Helsinki Declaration of 1975 and revised in 1983. The study was approved by the Ethics Committee of the Azienda Ospedaliera Universitaria of the Second University of Naples, which oversees both participating clinical centres. In addition, at the time of the first observation all patients signed an informed consent for the collection and storage of biological samples and for the anonymous use of their data in clinical research.
For each patient a sample of plasma was obtained at the first observation, stored at −40°C and never thawed until used for this investigation.
A follow up of at least 6 months was planned and 120 (87%) of the 138 patients enrolled in this study were followed up, whereas 18 (13%) dropped out because of lack of compliance. Patients were considered to have recovered from AVH-B if a steady normalization of AST/ALT serum levels and HBsAg serum clearance were achieved within 6 months from the onset of symptoms; the persistence of HBsAg in serum for more than 6 months was considered a sign of progression to chronicity.
Clearance of HBsAg after the acute phase of the illness confirmed the diagnosis of AVH-B in 118 patients, as this serological event is unusual in patients with a reactivation of HBV chronic infection. In addition, of the remaining 20 patients enrolled in this study, 16 had tested HBsAg negative 3–12 months before the onset of symptoms and were found to be HBsAg positive at hospitalization. Overall, the diagnosis of acute hepatitis B was confirmed by changes in the HBsAg serology in 134 (97.1%) of the 138 patients enrolled.
Routine methods
Hepatitis A virus (HAV), HBV, hepatitis C virus (HCV), HDV and HIV serum markers were sought using commercial immunoenzymatic assays (Abbott Laboratories, North Chicago, IL, USA, for HBsAg, anti-HBs, anti-HBc (total and IgM), anti-HAV (total and IgM) and anti-HIV 1 and 2; DiaSorin, Saluggia, VC, Italy, for anti-HDV IgG and anti-HDV IgM; Ortho Diagnostic Systems, Neckargemund, Germany, for anti-HCV). Liver function tests were performed applying routine methods.
HBV molecular methods
Plasma samples of all patients were tested for HBV DNA, HBV genotype and mutants in the polymerase region.
Plasma HBV DNA was sought by real-time PCR, as previously described 19; by this method, the detection limit in plasma samples is estimated at around 40 IU/mL. Hepatitis B virus genotypes were determined by phylogenetic analysis of sequences of 400 nucleotides of the S region, as previously described 20. The identification of mutants in the polymerase region was performed by direct sequencing of the region and by an allele-specific PCR identifying the lamivudine-resistant strains 204V and 204I, as previously described 11, which allowed the detection of primary and compensatory mutations at a level of frequency <5% of the viral population.
Hepatitis C virus genotyping was performed by a Line-Probe-Assay (INNO-LIPA HCV II, Innogenetics, Zwigndrecht, Belgium), which allows the identification of the six major genotypes and their subtypes (1a, 1b, 2a/2c, 2b, 3a, 3b, 3c, 4a, 4b, 4c/4d, 4f, 4h, 5a and 6a), according to the classification based on the amplification of the NS5 region of the HCV genome. HCV RNA was quantified by performing a real-time PCR in a Light cycler 1.5 (Roche Diagnostics, Branchburg, NJ, USA); by this method, the detection limit in plasma samples is estimated at around 40 IU/mL.
Statistical analysis
Continuous variables were summarized as mean and standard deviation, and categorical variables as absolute and relative frequencies. Differences in the mean were evaluated by an unpaired Student's t test, and the chi-squared test was applied to categorical variables. Odds ratios, with 95% CI, were estimated by a logistic regression model to evaluate the relationship between severe acute hepatitis B and age, sex, active intravenous drug use, alcohol intake, negativity for HBV DNA at baseline and presence of HCV infection. A p value <0.05 was considered to be statistically significant.
Results
The demographics and initial clinical, biochemical and virological characteristics of the 138 patients with AVH-B are shown in Table 1. The median age was 32 years (interquartile range 27–40) and males predominated (77.5%). A major risk factor for the acquisition of HBV infection was identified in 87.7% of the 138 patients investigated. Unsafe sexual activity and intravenous drug use were the most frequent (40.6% and 39%, respectively) risk factors. Thirty-eight (27.5%) patients had a history of alcohol abuse. The majority (74.6%) of patients were infected by HBV genotype D (Table 1).
| No. of cases | 138 |
|---|---|
| Age, years, Median (interquartile range) | 32 (27–40) |
| Males, n (%) | 107 (77.5) |
| Reporting a history of, n (%) | |
| Unsafe homosexual contact | 9 (6.5) |
| Unsafe heterosexual contact | 47 (34.06) |
| IVDUa | 55 (39) |
| Surgery | 10 (7.2) |
| Declaring no risk factor | 17 (12.3) |
| With alcohol abuse, n (%) | 38 (27.5) |
| Days after the onset of symptoms, mean ± SD | 8.35 ± 5.35 |
| AST, IU/L, n.v. 15–35, mean ± SD | 1874.6 ± 1059.7 |
| ALT, IU/L, n.v. 15–35, mean ± SD | 2668.7 ± 1226.85 |
| Total bilirubin, mg/dL, mean ± SD | 15.6 ± 8.8 |
| Prothrombin activity, %, mean ± SD | 63.15 ± 21.3 |
| With severeb or fulminantc hepatitis, n (%) | 19 (13.8) |
| HBV-DNA-negative patients, n (%) | 20 (14.5) |
| HBV DNA, copies/mL, mean ± SD | 171 335 790 ± 575 617 588 |
| HBV genotype, n (%): | |
| A | 13 (9.4) |
| D | 103 (74.6) |
| E | 11 (8) |
| F | 7 (5.1) |
| G | 4 (2.9) |
| HBeAg, n (%): | |
| Positive | 62 (44.9) |
| Negative | 76 (55.1) |
| rtM204V/I, n (%): | |
| Positive | 24 (17.4) |
| Negative | 96 (69.7) |
| Data not available | 18 (13.04) |
| HCV-Ab, n (%) | |
| Positive | 34 (24.6) |
| Negative | 103 (74.6) |
- a IVDU, intravenous drug use.
- b Severe hepatitis: development of ascites or of a progressive reduction in prothrombin activity to below 35% in the absence of porto-systemic encephalopathy;
- c Fulminant hepatitis: porto-systemic encephalopathy associated with a rapid progressive reduction in prothrombin activity to below 35%.
Thirty-four (24.6%) patients had been found to be anti-HCV/HCV-RNA positive 12 months or more before the onset of AVH-B, none of whom had undergone percutaneous liver biopsy or a non-invasive evaluation of liver fibrosis, and all of whom had become HCV-RNA negative by the onset of AVH-B and remained so throughout the 6-month observation period (Table 1).
The HBV polymerase region was explored in 110 (87%) patients, as a plasma sample was no longer available for the remaining 28. No nucleos(t)ide analogue-associated mutation was identified by sequencing the polymerase region, but HBV strains carrying the rtM204 substitution were detected in 24 (21.8%) patients by the allele-specific PCR assay (Table 1). More precisely, 18 patients showed the rtM204V mutation, five showed the rtM204I and one showed both the rtM204I and rtM204V.
AVH-B was severe in 13 (9.4%) of the 138 patients enrolled, and fulminant in six (4.3%) (Table 1). Of the 13 patients with severe AVH-B, three developed ascites and ten developed a progressive reduction in prothrombin activity to below 35%. All of these 13 patients recovered and cleared HBV infection during the follow up. Six patients developed porto-systemic encephalopathy and showed a rapid reduction in prothrombin activity to below 35%, indicating a fulminant course of the illness. Of these six patients, three recovered, two underwent successful liver transplantation and one died because no liver was available for transplantation. Of the 119 patients with a normal clinical course, 101 were followed up for at least 6 months and 34 were lost to follow up for lack of compliance. Of the 101 patients, 99 (98%) recovered and cleared HBV infection and two (2%) progressed to chronicity. Seroconversion to anti-HBs was observed in 64 (64.6%) of the 99 patients who recovered.
The differences in the initial characteristics between the 19 patients with severe or fulminant AVH-B and the 119 patients with a normal clinical course are shown in Table 2. These two groups were similar for age, prevalence of males and prevalence of patients with alcohol abuse. Compared with patients with a normal clinical course, those with severe or fulminant AVH-B were more frequently intravenous drug users (63.2% versus 36.1%, p 0.04), showed significantly higher serum levels of aminotransferases (AST, mean ± SD: 3549 ± 1786 IU/mL versus 1667 ± 862, p 0.001; ALT, mean ± SD: 4306 ± 2889 versus 2424 ± 952, p 0.001) and of total bilirubin (19.5 ± 9.6 mg/dL versus 15 ± 8.6, p 0.03) and were more frequently HBV-DNA negative (p <0.05) (Table 2).
| Acute hepatitis B | ||||
|---|---|---|---|---|
| Severea | Fulminantb | Severe and fulminant | With a normal clinical course | |
| Number of patients | 13 | 6 | 19 | 119 |
| Age, years, Median (interquartile range) | 31 (27–39) | 26 (25.5–33.5) | 29 (25.5–39) | 32 (27–40) |
| Males n (%) | 12 (92.3) | 4 (66.7) | 16 (84) | |
| Reporting a history of, n (%) | ||||
| Unsafe homosexual contact | 0 | 0 | 0 | 9 (7.6) |
| Unsafe heterosexual contact | 2 (15.4) | 3 (50) | 5 (26.3) | 42 (35.3) |
| IVDUc | 9 (69.2) | 3 (50) | 12 (63.2) a | 43 (36.1) b |
| Surgery | 1 (7.8) | 0 | 1 (5.3) | 9 (7.6) |
| Declaring no risk factors | 1 (7.8) | 0 | 1 (5.3) | 16 (13.4) |
| With alcohol abuse, n (%) | 5 (38.4) | 3 (50) | 8 (42) | 30 (25.2) |
| Days after onset of symptoms, mean ± SD | 7.5 ± 5.2 | 9.3 ± 3.7 | 7.8 ± 4.8 | 8.4 ± 5.4 |
| AST, IU/L, n.v. 15–35, mean ± SD | 2938.6 ± 1678.7 | 3963.2 ± 164.6 | 3549 ± 1786 c | 1667.2 ± 862.2 d |
| ALT, IU/L, n.v. 15–35, mean ± SD | 3684.1 ± 2041.2 | 5332 ± 4335.6 | 4306 ± 2889 e | 2423.6 ± 951.9 f |
| Total bilirubin, mg/dL, mean ± SD | 18.9 ± 10.4 | 21.8 ± 7.2 | 19.5 ± 9.6 | 15 ± 8.,6 |
| Prothrombin activity,%, mean ± SD | 37.1 ± 15.9 | 23.8 ± 12,6 | 35.7 ± 15.9 | 68 ± 18.4 |
| HBV-DNA-negative patients, n (%) | 2 (15.4) g | 4 (66.7) h | 6 (31.6) | 14 (11.8) |
| HBV DNA, copies/mL, mean ± SD | 5.1E8 ± 1.1E9 | 3E4 ± 3E4 | 1.4E6 ± 3.6E6 | 1.3E8 ± 4E8 |
| HBV genotype, n (%) | ||||
| A | 0 | 0 | 0 | 13 (10.9) |
| D | 9 (69.2) | 5 (83.3) | 14 (73.7) | 89 (74.8) |
| E | 2 (15.4) | 0 | 2 (10.5) | 9 (7.6) |
| F | 2 (15.4) | 0 | 2 (10.5) | 5 (4.2) |
| G | 0 | 1 (16.7) | 1 (5.3) | 3 (2.5) |
| HBeAg, n (%) | ||||
| Positive | 4 (30.8) | 2 (33.3) | 6 (31.6) | 56 (49.5) |
| Negative | 9 (69.2) | 4 (66.7) | 13 (68.4) | 63 (52.9) |
| rtM204V/I, n (%) | ||||
| Positive | 3 (23.1) | 0 | 3 (15.8) | 21 (17.6) |
| Negative | 8 (61.5) | 4 (66.7) | 11 (57.9) | 84 (70.6) |
| Datum not available | 2 (15.4) | 2 (33.3) | 5 (26.3) | 14 (11.8) |
| HCV-Ab, n (%) | ||||
| Positive | 7 (53.8) | 4 (66.7) | 11 (57.9) i | 23 (19.3) l |
| Negative | 6 (46.1) | 2 (33.3) | 8 (42.1) | 96 (80.7) |
- a Severe hepatitis: development of ascites or a progressive reduction in prothrombin activity to below 35% in the absence of porto-systemic encephalopathy;
- b Fulminant hepatitis: porto-systemic encephalopathy associated with a rapid progressive reduction in prothrombin activity to below 35%,
- c IVDU, intravenous drug use.
- Differences significant to the statistical analysis: a vs. b: p 0.04; c vs d: p 0.001; e vs. f: p 0.001; g vs. h p 0.04; i vs. l: p 0.0008.
All six patients with fulminant hepatitis had an HBV DNA load lower than 1 × 10E5 and were more frequently HBV-DNA negative (66.7%) than the 119 patients with a normal clinical course (11.8%, p <0.01) and the 13 with severe AVH-B (15.4%, p 0.04) (Table 3).
| Acute hepatitis B | ||||
|---|---|---|---|---|
| Severea | Fulminantb | Severe and fulminant | With a normal course | |
| Number of patients | 13 | 6 | 19 | 119 |
| HBV-DNA-positive patients, n (%) | ||||
| >10E7 copies/mL | 5 (38.5) | 0 | 5 (26.3) | 35 (29.4) |
| 1 × 10E6-1 × 10E7 copies/mL | 4 (30.8) | 0 | 4 (21.05) | 22 (18.5) |
| 1 × 10E5-1 × 10E6 copies/mL | 0 | 0 | 0 | 16 (13.4) |
| 1 × 10E4-1 × 10E5 copies/mL | 2 (15.4) | 1 (16.7) | 3 (15.8) | 21 (17.6) |
| <1 × 10E4 | 0 | 1 (16.7) | 1 (5.3) | 11 (9.2) |
| Negative | 2 (15.4) a | 4 (66.7) b | 6 (31.6) c | 14 (11.8) d |
- a Severe hepatitis: development of ascites or a progressive reduction in prothrombin activity to below 35% in the absence of porto-systemic encephalopathy;
- b Fulminant hepatitis: porto-systemic encephalopathy associated with a rapid progressive reduction in prothrombin activity to <35%,
- Differences significant to the statistical analysis: a vs. b: p 0.01; c vs. d: p 0.03.
The prevalence of patients with the rtM204V/I mutant was similar in patients with severe or fulminant AVH-B and in those with a normal clinical course (Table 2). Chronic HCV infection was more frequent in the 19 patients with severe or fulminant AVH-B (57.9%) than in those with a normal course (19.3%, p 0.0008) (Table 2). Conversely, severe or fulminant AVH-B occurred in one-third of the anti-HCV-positive patients and in less than 8% of the anti-HCV-negative patients. The multivariate logistic regression analysis identified a pre-existing HCV chronic infection as the only factor independently associated with a severe or fulminant clinical course of AVH-B (OR 4.89, 95% CI 1.5–15.9, p 0.01) (Table 4).
| Parameter | Odds ratio | 95% CI lower upper | p |
|---|---|---|---|
| Gender | |||
| Male vs. Female | 1.63 | 0.31–8.60 | 0.56 |
| Age | |||
| 1.01 | 0.97–1.06 | 0.60 | |
| Risk factor | |||
| IVDA vs. non IVDA | 1.69 | 0.36–8.01 | 0.51 |
| History of alcohol use | |||
| Yes vs. No | 1.82 | 0.59–5.60 | 0.30 |
| HBV DNA | |||
| Negative vs. Positive | 2.87 | 0.83–9.90 | 0.10 |
| Anti-HCV | |||
| Positive vs. negative | 4.89 | 1.50–15.94 | 0.01 |
- a HBV, hepatitis B virus; HCV, hepatitis C virus; IVDA, intravenous drug abuse.
Discussion
In the present study a pre-existing HCV chronic infection was identified as the only factor independently associated with a severe clinical presentation of AVH-B, an association most probably due to the combined effect of the liver lesions caused by AVH-B infection and the pre-existing histological abnormalities related to HCV chronic infection. Indeed, severe or fulminant AVH-B was significantly more frequent in anti-HCV-positive patients than in the anti-HCV-negative patients, in full agreement with the data of our previous study 15, which, however, did not investigate factors associated with the severity of the clinical course of AVH-B.
All other presumed risk factors investigated in the present study, that is, age, sex, history of intravenous drug use, negative versus positive HBV DNA and a history of alcohol abuse were not found to be independently associated with a more severe clinical course, even though patients with severe or fulminant AVH-B more frequently than those with a normal clinical course had a history of intravenous drug use, alcohol intake and an undetectable or low HBV load at baseline. In other studies, the patients who died of fulminant hepatitis B compared with those with less severe disease had had a significantly more frequent exposure to alcohol, cocaine and amphetamine 14, 21, 22, factors, however, not identified as independently associated with a severe or fulminant course of the disease.
Hepatitis B virus acute infection exerted a strong inhibition of HCV chronic replication in patients who had been anti-HCV/HCV-RNA positive 1 year or more before the onset of AVH-B, as all of them were found to be HCV-RNA negative/anti-HCV positive, both at their first observation after the onset of symptoms of AVH-B and during the 6-month follow up. These data are similar to those reported in our previous study on a similar setting of patients, two-thirds of whom became HCV-RNA positive during a 4- to 6-year follow up and one-third of whom eradicated HCV chronic infection 15, HCV clearance being significantly more frequent in patients with severe AVH-B.
Several other models of superinfection or co-infection of the human hepatitis viruses have been described: HCV superinfection inhibits HBV replication in patients with HBV chronic infection 23, 24; HAV superinfection impairs both HBV and HCV replication in patients with a pre-existing HBV or HCV chronic infection, respectively 25; HDV superinfection exerts a strong suppression of HBV chronic replication 26, and a reciprocal viral inhibition has been described in HBV/HCV concurrent acute infection, a model of co-infection frequently characterized by the clearance of HBV and the progression to chronicity of HCV infection 27.
Also HBV/HCV or HBV/HDV/HCV chronic co-infections are characterized by a reciprocal inhibition of viral replication and by a more severe clinical presentation compared with HBV or HCV chronic mono-infection 28. A similar difference in the clinical presentation has been confirmed in a more recent study on 1257 patients with chronic HCV infection from New York City, which showed that liver fibrosis stage 3 or 4 was significantly more common in the 26 patients with HBV-HCV dual infection than in 658 HCV-mono-infected patients 29.
AVH-B patients with an undetectable or low HBV DNA serum level at the first observation should be closely monitored for possible nucles(t)ide treatment as this virological finding occurred more frequently in patients with fulminant hepatitis than in those with a severe form of the disease, in analogy with a previous observation showing a lower initial HBV load in patients with fulminant hepatitis than in those with a normal clinical course 30.
No patient in the present study was treated with nucleos(t)ide analogues, as these drugs were not licensed for AVH-B in Italy at the time severe or fulminant hepatitis occurred. Current clinical practice advises the use of Tenofovir or Entecavir, drugs of high potency and high genetic barriers, to treat the more severe forms of AVH-B 31, a practice that may reduce the mortality rate and/or the need for liver transplantation 6, 9, 12.
The frequent occurrence of severe or fulminant AVH-B in patients with HCV chronic infection should strongly urge the physicians in care and the health authorities to extend HBV vaccination to patients with HCV chronic infection. This practice remains poorly applied worldwide, particularly in developing countries where HCV chronic carriers are at a high risk of HBV superinfection, despite being recommended by several international and national guidelines and healthcare institutions 31.
Transparency Declaration
All the authors of the manuscript declare that they have no conflict of interest in connection with this paper.
Funding
This study was supported in part by a grant from Regione Campania “Progetti per il miglioramento della qualità dell'assistenza, diagnosi e terapia del paziente affetto da AIDS nei settori: immunologia, coinfezioni, informazione e prevenzione”, 2008.
