Occult hepatitis B virus infection in a North American adult hemodialysis patient population

Abstract

Hepatitis B virus (HBV) infections continue to occur in adult hemodialysis units. A possible contributing factor is the presence of occult HBV (serum hepatitis B surface antigen [HBsAg] negative but HBV DNA positive). Two hundred forty-one adult hemodialysis patients were screened for occult HBV. HBV DNA testing was performed by real-time polymerase chain reaction (PCR) with 2 independent primer sets (core promoter and surface). Two (0.8%) of the 241 patients were HBsAg positive. Of the remaining 239 HBsAgnegative patients, 9 (3.8%) were HBV DNA positive. Viral loads in these individuals were low (10 2 -10 4 viral copies/mL). Seven of the 9 (78%) were nt 587 mutation (sG145R mutant) positive. Demographic, biochemical, and HBV serological testing did not help to identify those with occult HBV. In conclusion, the prevalence of occult HBV in adult hemodialysis patients in this North American urban center is approximately 4 to 5 times higher than standard HBsAg testing would suggest. The majority of these infections are associated with low viral loads and a high prevalence of the sG145R mutant. Finally, the demographic, biochemical, and/or serological features of HBV DNA-positive subjects do not distinguish these individuals from the remainder of the dialysis patient population. (HEPATOLOGY 2004; 40:1072-1077.) D espite the development of an effective hepatitis B virus (HBV) vaccine and extensive infection control guidelines, HBV infections continue to occur in dialysis units throughout North America and Europe. 1-3 Based on the results of hepatitis B surface antigen (HBsAg) testing, the incidence of such infections is thought to be 0.05%-1% per year. 4 However, this likely represents an underestimate of the true incidence, as the use of more sensitive monoclonal-based assays for HBsAg detection increase positive findings in dialysis patients by 120%. 5 The relatively low acceptance and response rates to the HBV vaccine among dialysis patients likely contributes to ongoing transmission, as does the need for vaccine boosts to maintain antibody to HBsAg (anti-HBs) at protective levels. 4,6 -8 Additional contributing factors include "breakdowns" in the application of universal and/or dialysis-specific infection control measures. 4,7,9 With the development of specific and sensitive polymerase chain reaction (PCR)-based testing for HBV DNA, the presence of occult HBV infection (HBV DNA positivity in the setting of negative serum HBsAg) represents yet another possible explanation for ongoing transmission.To date, few studies have documented the prevalence of occult HBV infection in renal dialysis patients. In 3 small studies of 33, 5, and 67 HBsAg-negative dialysis patients, 50%, 40%, and 0%, respectively, were HBV DNA positive. 10 -12 Of note, the majority of HBV DNApositive individuals in these studies had serological evidence of previous HBV infection (HBV seropositive), but as many as 39% were HBV seronegative.The present study documents the prevalence of HBV DNA positivity in a large, North American renal dialys...

Occult HBV infection status among chronic hepatitis C and hemodialysis patients in Northeastern Egypt: regional and national overview

“…Marked variation was found by comparing these rates with OBI prevalence rates reported in other related national or international studies (23) (24) (35) (36) (37) (38) (39) .This variation may be attributed to differences in the sample size of the study populations, demographics, immunologic status of the studied patients, endemicity of HBV infection, levels of viral DNA in the blood, sampling conditions and the types of diagnostic tool(s) used for diagnosis (40) . This comparison also revealed that the prevalence of OBI in our target HD patients was relatively low, possibly due to the application of safety precautions during the dialysis process in these units and the implementation of the routine vaccination program.…”

“…This result is in accordance with the fi nding that OBI is more prevalent in seropositive patients who are positive for anti-HBc and/or anti-HBs (23) (29) (37) (42) (43) . The occurrence of occult infection despite the presence of neutralizing an ti-HBs can result from mutations affecting the S region of the HBV genome (39) . However, the absence of all HBV serological markers (even anti-HBc) in some HBV DNApositive patients strengthens the proposal that the detection of viral DNA is the gold standard for the diagnosis of OBI.…”

Occult hepatitis B virus infection in Egyptian hemodialysis patients with or without hepatitis C virus infection

“…Although the incidence of occult HBV in our hemodialysis patient population is not high compared with that in the general population, it is considerably high compared with other studies. In a study by Minuk et al 16 including 239 hemodialysis patients who were hepatitis B surface antigen-negative, 9 (3.8%) patients were HBV DNA-positive by real-time PCR. In another study by Yakaryilmaz et al 17 of 188 patients with end-stage renal disease on maintenance hemodialysis (mean duration 98 ± 66 months), occult HBV was identified in only five (2.7%) patients.…”

Hepatitis B Virus (HBV) Variants in Hemodialysis Patients

“…Parenteral exposure also favors contamination by HCV (Dai et al, 2001). The studies performed up to now on hemodialysis patients provide widely divergent results, reporting a prevalence of occult HBV that ranges from 0% to 36% (Besisik et al, 2003;Fabrizi et al, 2005;Goral et al, 2006;Kanbay et al, 2006;Minuk et al, 2004;Motta et al, 2010;Siagris et al, 2006). These apparent discrepancies may be explained by significant differences in the prevalence of HBV infection in different geographic regions and/or by the detection limits of different HBV-DNA assays.…”

“…These apparent discrepancies may be explained by significant differences in the prevalence of HBV infection in different geographic regions and/or by the detection limits of different HBV-DNA assays. In this context, it is of note that several authors consider occult HBV as a possible source of virus spread in hemodialysis units, thus representing a risk of infection for both patients and staff, and suggest some precautions including HBV DNA screening for all hemodialysis patients (Minuk et al, 2004).…”