Surveillance and control of blood-borne virus infections in haemodialysis units

Elimination of HDV: Epidemiologic implications and public health perspectives

Hepatitis delta virus (HDV) infection causes the severest form of viral hepatitis in humans. Discovered in 1977, it was considered an infection prevalent in the eastern Mediterranean region. Today it is recognized as a global infection of public health importance, however accurate prevalence remains uncertain because of lack of good epidemiological studies. Under-screening for HDV is the single most important factor in under-estimating the true burden of infection. Urgent efforts are therefore needed to apply reliable screening tools and robust surveillance methodologies to study HDV. There is now a move by major hepatology societies to recommend HDV antibody testing in all persons with HBV infection. Important differences also need to be recognized between countries considered endemic or non-endemic countries. While the endemic infections likely spread horizontally in the general population, and is quite often nosocomial, in non-endemic countries special populations may carry the greater burden, such as persons with injection drug use and various sexual exposures. Even in endemic countries, HDV often exists in significant pockets of the general population. HDV has been categorized as an orphan infection due to lack of approved therapies. Recently there have significant advances in therapy and further clinical trials continue. However, as new therapies are approved, equitable access to the medications will become a major public health issue, particularly because most HDV patients live in low or low middle income countries.

A Large Nosocomial Outbreak of Hepatitis C Virus Infections at a Hemodialysis Center

Objective:

To identify modes of HCV transmission during an outbreak of HCV infection in a hemodialysis unit.

Design:

An epidemiologic study, virologie analysis, assessment of infection control practices and procedures, and technical examination of products and dialysis machines.

Setting:

A private hemodialysis unit treating approximately 70 patients.

Patients:

Detection of HCV RNA by PCR was performed among patients receiving dialysis in 2001. Case-patients were patients who had a first positive result for HCV RNA between January 2001 and January 2002 and either acute hepatitis, a seroconversion for HCV antibodies, or a previous negative result. Three control-patients were randomly selected per case-patient.

Results:

Of the 61 patients treated in the unit in 2001 and not infected with HCV, 22 (36.1%) became case-patients with onset from May 2001 to January 2002 for an incidence density rate of 70 per 100 patient-years. Phylogenic analysis identified four distinct HCV groups and an index case-patient for each with a similar virus among patients already known to be infected. No multidose medication vials or material was shared between patients. Connection to a dialysis machine by a nurse who had connected an HCV-infected patient “just before” or “one patient before” increased the risk of HCV infection, whereas using the same dialysis machine after a patient infected with HCV did not. Understating, lack of training, and breaches in infection control were documented. Direct observation of practices revealed frequent flooding of blood into the double filter on the arterial pressure tubing set.

Conclusions:

During this outbreak, HCV transmission was mainly patient to patient via healthcare workers' hands. However, transmission via dialysis machines because of possible contamination of internal components could not be excluded.

Problems associated with hemodialysis and travel

BACKGROUND

While there is a recognized risk of hepatitis C acquisition associated with dialysis away from the "home" center, there is little documented data on the effect that dialysis while traveling has on the dialysis patient's health. This study was designed to examine the incidence of travel within a hemodialysis population and to ascertain whether travel was associated with morbidity for patients on hemodialysis.

METHODS

Travel data were collected prospectively over a 6-month period, from April 2009, for all patients receiving maintenance hemodialysis across our dialysis centers. Biochemical, microbiological, and hematological parameters as well as hepatitis serology and antibiotic starts were recorded for 12 weeks prior to and following dialysis away from center.

RESULTS

A total of 172 individuals traveled on 200 occasions. The blood stream infection rate for travelers with a central venous catheter was 0.25 versus 0.83/1,000 access days (p = 0.038) in the 12 weeks pre-travel versus post-travel. Parenteral and oral antibiotic starts were both significantly elevated post-travel and were mainly instituted for either chest or urinary sepsis. There was evidence of raised inflammatory markers and anemia on return to center but no evidence of hepatitis B or hepatitis C seroconversion.

CONCLUSIONS

Travel and dialysis away from a patient's usual hemodialysis unit is a common occurrence but is associated with an increased risk of bacterial infection, anemia, and inflammatory response. This study provides evidence for the concern that hemodialysis away from center is associated with increased morbidity.

Frequency and Genotype of Hepatitis D Virus Infection in Patients Infected with HIV and Those Undergoing Hemodialysis

BACKGROUND

Hepatitis D virus (HDV) is a defective virus dependent on hepatitis B virus (HBV) for its replication. Due to HDV transmission routes, patients undergoing hemodialysis and those with HIV infection are at risk of acquiring HDV.

OBJECTIVES

This study was aimed to determine the frequency and genotype of HDV infection among patients with HIV infection and those undergoing hemodialysis.

PATIENTS AND METHODS

720 cases including 120 patients undergoing hemodialysis, and 600 patients with HIV infection were studied. All cases with positive results for HBsAg were evaluated for the presence of anti-HDV antibodies. Samples with Anti-HDV positive results were subjected to nested PCR for HDV-RNA confirmation, and sequenced for HDV genotype determination.

RESULTS

HBsAg was found in 9 (7.5%) of 120 patients undergoing hemodialysis, and 9 (1.5%) of 600 patients with HIV infection. 3 (33.3%) of patients undergoing hemodialysis with positive results for HBsAg, and 5 (55.5%) of cases with HIV infection and positive results for HBsAg, had positive findings for anti-HDV which were then subjected to nested PCR. The amplification results confirmed that in 3 (37.5%) samples HDV-RNA was detected. Overall 2.5% of patients undergoing hemodialysis, and 0.8% of cases infected with HIV had positive results for anti-HDV and 1.7% and 0.2% of cases undergoing hemodialysis and patients infected with HIV had positive findings for HDV-RNA respectively. All of the HDV isolates were clustered in clade 1.

CONCLUSIONS

The survey showed that overall HDV frequency was not high in our high risk cases. Therefore, practitioners and health care managers should become aware of the risk of dual infection with HBV and HDV especially in high risk patients.

Human Herpesvirus 6 Infection in Hemodialysis and Peritoneal Dialysis Patients

Background

Human herpesvirus 6 (HHV-6) infection occurs worldwide and can be reactivated from latency during periods of immunosuppression, especially after organ transplantation. No previous study has evaluated the influence of dialysis type on HHV-6 infection. The aim of the present study was to determine the prevalence of HHV-6 antibodies in hemodialysis (HD) and peritoneal dialysis (PD) patients.

Methods

W e studied 36 PD patients, 35 HD patients, and 20 healthy subjects, all with no history of organ transplantation. After systematic inquiries and a physical examination, blood was drawn for determination of biochemical parameters, cytomegalovirus immunoglobulin M (IgM) and immunoglobulin G (IgG), hepatitis B surface antigen, and the hepatitis C and human immunodeficiency virus antibodies. Titers of HHV-6 IgM and IgG antibodies were determined by ELISA.

Results

Titers for HHV-6 IgM antibody were positive in 9 HD patients (25.7%), 8 PD patients (22.2%), and 2 control subjects (10.0%, p > 0.05). More HD patients (20.0%) than PD patients (5.6%, p = 0.07) or control subjects (0.0%, p =0.03) were positive for HHV-6 IgG antibody. In HD patients, HHV-6 IgG seropositivity and duration of dialysis were positively correlated (R = 0.33, p = 0.05).

Conclusions

Infection with HHV-6 is not rare in PD and HD patients. In addition, HHV-6 IgG seropositivity was significantly higher in H D patients than in control subjects and approached significance when compared with seropositivity in PD patients. Moreover, in HD patients, HHV-6 IgG seropositivity correlated with duration on HD. These preliminary findings provide insight into the pre-transplantation period for patients and may aid our understanding of how to best protect patients against HHV-6 after transplantation.

Variability of hepatitis B testing in British Columbian ESRD patients: the case to focus on implementation of guidelines

BACKGROUND

Hepatitis B virus (HBV) immunization protocols are routinely followed in dialysis units. Recommendations for retesting and booster dose administration are variable and less well known.

DESIGN

Quality improvement report.

SETTING & PARTICIPANTS

Provincial dialysis cohort in all 5 regional centers in British Columbia (n = 1,055).

QUALITY IMPROVEMENT PLAN

(1) Describe the variations in HBV testing practice patterns between centers and modalities of dialysis, (2) propose an evidence-based protocol for HBV follow-up testing, and (3) compare the current practice for HBV follow-up testing with the protocol.

MEASURES

(1) Number of HBV tests performed based on geographic center and dialysis modality; (2) tabulation of local, national, and international guidelines to determine concordance and develop British Columbian protocol, and (3) percentage of patients who received recommended HBV testing based on protocol.

RESULTS

(1) Significant variation noted in HBV testing frequency among the 5 regional centers and between hemodialysis and peritoneal dialysis patients (P < 0.001); (2) current available guidelines generally are concordant, but vary in regard to frequency of follow-up testing; and (3) comparing recommended testing frequency with actual testing, 50% of patients were tested as recommended; 13%, less than recommended; and 37%, more than recommended. Hemodialysis patients often were tested more than recommended (hemodialysis, 47% versus peritoneal dialysis, 16%; P < 0.01). Patients with current or past HBV infection were tested more than recommended (P < 0.01). All variability remained significant when adjusted for age, sex, and dialysis therapy duration in a multivariate model.

LIMITATIONS

The cohort was ascertained from laboratory data; therefore, information for vaccination and booster dose administration was not available.

CONCLUSION

In a cohort of dialysis patients initially screened for hepatitis B, 50% of patients are being appropriately monitored with retesting compared with an evidence-based protocol. Patients with known HBV infection and hemodialysis patients are being tested more than recommended. Adherence to a protocol for retesting would ensure appropriate follow-up and reduce unnecessary retesting, potentially leading to significant cost savings.

Passage from India: an outbreak of hepatitis B linked to a patient who acquired infection from health care overseas

OBJECTIVES

To investigate a nosocomial and community outbreak of hepatitis B to establish how the infections might have occurred.

STUDY DESIGN

Descriptive study.

METHODS

Four cases of hepatitis B who had stayed in hospital during their incubation periods, a case in one of their household contacts, and three further cases in the community were all linked to a patient who had been infected during a renal transplant in India. Medical records from cases were reviewed to extract information about risk factors for infection. Working practices were reviewed to determine how nosocomial transmissions might have occurred. 'Look-back' exercises were conducted to identify and follow-up other patients and staff who might also be at-risk of infection. Hepatitis B viral sequences from all cases were examined to determine whether they were related.

RESULTS

Viral DNA sequences from all nine cases were identical. The primary case had an extremely high viral load due to underlying immunosuppression. Three of the nosocomial transmissions occurred whilst the primary and secondary cases shared general medical wards; two whilst the primary case was in standard isolation. No clear routes of infection were identified. The fourth was associated with a failure of infection control in operating theatres.

CONCLUSIONS

Invasive medical procedures in high-prevalence countries carry a clear risk of blood borne viral infections. There is a need for much better awareness of this risk, both among patients who are considering travelling for treatment, and the health professionals who will be caring for them on their return. Infections may be preventable through hepatitis B vaccination. Patients admitted to hospital following invasive medical procedures in high-prevalence countries should be nursed with stringent infection control measures until blood borne viral infections can be excluded. However, patients with hepatitis B who are highly infectious may transmit the virus despite high standards of infection control.