Dynamics of spreading of SARS-CoV-2 in a Belgian hemodialysis facility: The importance of the analysis of viral strains

In‐center maintenance hemodialysis (HD) patients are at high risk of acquiring coronavirus disease 2019 (COVID‐19) by cross‐contamination inside the unit. The aim of this study was to assess retrospectively the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) transmission during the very first pandemic phase (March–July 2020) in a cohort of in‐center maintenance HD patients and in nurses the same HD facility, using a phylogenetic approach. All SARS‐CoV‐2 quantitative reverse‐transcription polymerase chain reaction positive patients and nurses from our HD unit‐respectively 10 out of 98, and 8 out of 58‐ and two other positive patients dialyzed in our self‐care unit were included. Whole‐genome viral sequencing and phylogenetic analysis supported the cluster investigation. Five positive patients were usually dialyzed in the same room and same shift before their COVID‐19 diagnosis was made. Viral sequencing performed on 4/5 patients' swabs showed no phylogenetic link between their viruses. The fifth patient (whose virus could not be sequenced) was dialyzed at the end of the dialysis room and was treated by a different nurse than the one in charge of the other patients. Three nurses shared the same virus detected in both self‐care patients (one of them had been transferred to our in‐center facility). The epidemiologically strongly suspected intra‐unit cluster could be ruled out by viral genome sequencing. The infection control policy did not allow inter‐patient contamination within the HD facility, in contrast to evidence of moderate dissemination within the nursing staff and in the satellite unit. Epidemiologic data without phylogenetic confirmation might mislead the interpretation of the dynamics of viral spreading within congregate settings.

In‐center maintenance hemodialysis (HD) patients are at high risk of acquiring coronavirus disease 2019 by cross‐contamination inside the unit. In this study we assessed the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) transmission in a cohort of in‐center maintenance hemodialysis patients and in nurses the same HD facility in Brussels, Belgium, using whole‐genome viral sequencing and phylogenetic analysis.

All SARS‐CoV‐2 quantitative reverse‐transcription polymerase chain reaction (RT‐qPCR) positive patients (10 out 98) and nurses from our HD unit (8 out 58) and two other positive patients dialyzed in our self‐care unit were included. An intra‐unit cluster was suspected because five SARS‐CoV‐2 RT‐qPCR positive patients were dialyzed in the same room at the same time three times weekly.

The epidemiologically strongly suspected intra‐unit cluster could be ruled out by viral genome sequencing. In contrast, three nurses shared the same virus detected in both self‐care patients (one of them had been transferred to our in‐center facility).

Epidemiologic data without phylogenetic confirmation might mislead the interpretation of the dynamics of viral spreading within congregate settings.

Adjuvanted recombinant HBV vaccine (HBV-AS04) is effective over extended follow-up in dialysis population. An open-label non randomized trial

BACKGROUND

Patients on regular dialysis show a poor response to hepatitis B vaccine due to uremia. A recombinant HB vaccine (containing an improved adjuvant system AS04, HBV-AS04) has been licensed but the evidence on its efficacy and safety in dialysis population over the long term is extremely limited.

AIM

We have measured antibody (anti-HBs) persistence for up to 72 months in a large cohort of patients on long-term dialysis (with susceptibility to HBV infection) who underwent vaccination with HBV-AS04 vaccine.

METHODS

Patients were prospectively recruited to receive four 20-mcg doses of HBV-AS04 by intramuscular route (deltoid muscle). Two vaccine schedules were adopted: 0,1,2, and 3 month (n=217 patients) and 0,1,2, and 6 month (n=31 patients). Anti-HBs antibody concentrations were tested at 1,2,3, 4, 7 and 12 months and then every year up to 72 months. Multivariate analysis was made to find the baseline parameters that were associated with the immune response to HBV-AS04 vaccine.

RESULTS

Two hundred and seventy-two patients were included and 248 completed the study. At completion of vaccine schedule, the frequency of responders (anti-HBs titers≥10mIU/mL) was 81.5% (202/248) (mean anti-HBs antibody titers, 384.9±391.9mIU/mL), according to per-protocol analysis. On the grounds of univariate analysis, age was lower in responder than non- responder patients to HBV AS04 even if no statistical significance was achieved (P=0.09). The sero-protection rate at month 72 was 77% (7/9) (anti-HBs antibody titers, 184.9±360.1mIU/mL, P=0.001). Multivariate analysis found a relationship between sero-response rate and age (P=0.04). No major side effects and no de novo HBV episodes were observed.

CONCLUSIONS

Our open-label nonrandomized trial performed in a 'real-world' practice showed the persistence of anti-HBs antibody among responder patients over a very long follow-up. Studies with longer observation periods are under way.

Infection with hepatitis C virus in hemodialysis patients: An overview of the diagnosis and prevention rules within a hemodialysis center (Review)

Increase in the number of patients with chronic kidney disease (CKD) calls for improved management of these patients. In stage 5 CKD, when the initiation of renal replacement therapy (RRT) becomes necessary, there is an increase in the infection risk of the patients and immunological tests for hepatitis C virus (HCV) detection turn positive at an alarmingly higher rate compared to general population. With the introduction into clinical practice of diagnostic tests, the increased prevalence of HCV among CKD patients has been known since the 1990s. Also, the negative impacts of HCV infection on CKD evolution as well as the unfavorable evolution of grafts received by HCV infected patients are known. Chronic hemodialysis patients are a category of patients whose risk of HCV infection is substantial. Currently, in the hemodialysis centers, at the base of the transmission of HCV infection there are a multitude of factors. Infection with HCV has a different impact on patient with end-stage renal disease (ESRD). Comorbidities in this case have significant sources of mortality and morbidity. It was proven that the post transplantations problems were prevented and mortality was reduced for patients who were diagnosed with HCV and in whom the infection was treated before the kidney transplant (KT). Consequently, early detection of the infection and the application of specific treatment has a considerable impact on the outcome of the patients. Another important component of the management of HCV infection in the chronic hemodialysis patients is the prevention of the infection transmission by applying specific methods.

The prevention of hepatitis C virus transmission to hemodialysis patients and staff members

In this review article, we cover 4 topics very relevant to those involved in the care of hemodialysis (HD) patients and in the management of a HD unit. We start with an overview of the progress made over the last 25 years to reduce hepatitis C virus (HCV) transmission in HD. Next, we discuss the potential strategies to prevent the residual ongoing transmission of HCV to HD patients. Third, we discuss the actions to be taken if a seroconversion for HCV is nevertheless detected in a HD patient. Finally, we briefly discuss how best to protect HD staff members from occupationally acquired HCV infection.

Immunogenicity, antibody persistence, and safety of the 60 μg hepatitis B vaccine in hemodialysis patients: a multicenter, randomized, double-blind, parallel-controlled trial

BACKGROUND

To evaluate the immunogenicity, antibody persistence, and safety of the 60 µg hepatitis B vaccine in hemodialysis patients in China.

METHODS

We conducted a multicenter, randomized, double-blind, parallel-controlled trial including 352 hemodialysis patients who were centrally randomized in a ratio of 1:1 to receive a 20 µg (IM20 group) or 60 µg (IM60 group) recombinant hepatitis B vaccine at months 0, 1, and 6.

RESULTS

The vaccine-elicited antibody responses peaked at month 7, and declined at month 12. At month 7, the IM60 group had stronger GMC of anti-HBs, and a higher proportion of seroconversion and high-level response than the IM20 group did (P < 0.05). Better immune responses were observed in the IM60 group, especially for those aged or in the high-frequency hemodialysis population.

CONCLUSION

The high dose 60 µg recombinant hepatitis B vaccines elicited stronger immune responses than the 20 µg hepatitis B vaccine did among hemodialysis patients.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, number NCT02963714.

Meta-analysis: the impact of nutritional status on the immune response to hepatitis B virus vaccine in chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) typically show a diminished immune response to hepatitis B virus (HBV) vaccine compared with individuals with intact kidney function. A number of inherited or acquired factors have been implicated in this suboptimal response. Patients with chronic kidney disease frequently have a compromised nutritional status; however, the impact of malnutrition on the immune response to hepatitis B virus vaccine in chronic kidney disease patients remains unclear.

AIM

To evaluate the influence of nutrition status on the immune response to HBV vaccine in CKD population by performing a systematic review of the literature with a meta-analysis of clinical studies.

METHODS

Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effects pooled estimates of impaired vaccine response across the published studies. The risk of poor serological response to HBV vaccine in chronic kidney disease population according to nutritional parameters was regarded as the most reliable outcome end-point. Only studies performing multivariate analysis in order to make adjustments for potential confounders were included.

RESULTS

We identified seven studies (15,172 unique patients with CKD). The serum protection rate after a full course of recombinant or plasma-derived vaccine towards HBV ranged between 40 and 86%. Aggregation of study results showed an independent and adverse effect of poor nutrition status, as mostly detected by serum albumin levels, on the protection rate after HBV vaccine course; the summary estimate for adjusted RR was 1.50 with a 95% confidence interval (CI) of 1.02, 2.21; R( i ) = 0.01 (random-effects model). The P value for study heterogeneity was significant (Q = 0.0001). In the subgroup of patients who received HBV recombinant vaccine, the relative risk of impaired serological response after HBV vaccination was 1.63 (95% CI, 1.08, 2.45), R( i ) = 0.90, Q = 0.00001, with poor nutritional parameters at baseline.

CONCLUSIONS

An increased risk exists of impaired serologic response to HBV vaccine response among chronic kidney disease patients having poor nutrition status. Additional studies are needed to understand better the mechanisms underlying the relationship between nutritional status and serological response to HBV vaccine among patients with CKD.

Meta-analysis: the impact of diabetes mellitus on the immunological response to hepatitis B virus vaccine in dialysis patients

BACKGROUND

Patients on maintenance dialysis typically show a suboptimal immune response to hepatitis B virus vaccine compared with the non-uraemic population. A variety of inherited or acquired factors have been implicated in this diminished response. It is well known that patients with diabetes mellitus have a compromised immune system, and diabetic nephropathy is an important cause of chronic kidney disease. However, the impact of diabetes mellitus on the immune response to HBV vaccine in patients receiving long-term dialysis remains unclear.

AIM

To evaluate the influence of diabetes mellitus on the immune response to HBV vaccine in dialysis population by performing a systematic review of the literature with a meta-analysis of clinical studies.

METHODS

We used the random effects model of DerSimonian and Laird with heterogeneity and sensitivity analyses. The end-point of interest was the rate of patients showing seroprotective antibody against hepatitis B surface antigen at completion of vaccine schedule in the diabetic vs. the nondiabetic dialysis individuals.

RESULTS

We identified 12 studies involving 1002 unique patients on long-term dialysis. Aggregation of study results showed a significant decrease in response rates among the diabetic vs. the nondiabetic patients [pooled odds ratio=0.52 (95% CI 0.38-0.71)]. The P-value was 0.29 for our test of study heterogeneity. Stratified analysis in various subgroups of interest did not meaningfully change our results.

CONCLUSIONS

Our meta-analysis showed a clear association between diabetes mellitus and impaired response to hepatitis B virus vaccine in individuals on long-term dialysis. Such a relationship is biologically plausible. Vaccination schedules with adapted vaccine doses and frequent serum testing for loss of immunity against hepatitis B virus should be considered in patients on maintenance dialysis with diabetes mellitus.

Immunogenicity of an adjuvanted 2009 pandemic influenza A (H1N1) vaccine in haemodialysed patients

BACKGROUND

The 2009 pandemic of influenza A (H1N1) prompted an urgent worldwide vaccination campaign, especially of high-risk subjects, such as maintenance haemodialysis (HD) patients. Still the immunogenicity of the pandemic A (H1N1) vaccine in HD patients is unknown.

METHODS

We prospectively studied the immunogenicity of a monovalent adjuvanted influenza A/California/2009 (H1N1) vaccine (Pandemrix, GSK Biologicals, Rixensart, Belgium) in HD patients and controls. Antibody level was measured using a seroneutralization assay before (D(0)) and 30 days after (D(30)) a single 3.75 μg vaccine dose. Specimens were tested in quadruplicates. Geometric mean (GM) antibody titers were determined in each subject at D(0) and D(30). Seroconversion was defined as an increase in GM titers by a factor 4 or more.

RESULTS

Fifty-three adult HD patients [aged 71 ± 10, 58.5% males, on HD for a median of 38 (3 - 146) months] and 32 control subjects (aged 47.3 ± 14, 31.3% males) were analyzed. Baseline GM titers were similar in HD patients and controls [7.9 (6.6 - 9.6) vs 10 (6 - 17); p = 0.69]. Seroconversion was observed in 30 (93.8%) controls and 34 (64.2%) HD patients (p = 0.002). In addition, GM titers at D(30) were significantly higher in controls than in HD patients [373 (217 - 640) vs 75.5 (42.5 - 134); p = 0.001]. HD patients were significantly older than controls (p < 0.001) and more likely to be males (p = 0.02). However, by multivariate analysis, HD status [OR 0.13 (0.02-0.78), p = 0.03], but neither age [OR 0.99 (0.96 - 1.03); p = 0.7] nor male gender [OR 1.31 (0.45 - 3.85); p = 0.63] was independently associated with seroconversion. The vaccine was generally well tolerated by HD patients.

CONCLUSIONS

Only 64% of chronic HD patients developed seroconversion after a single dose of adjuvanted influenza A (H1N1) vaccine, a much lower rate than in controls (94%). These results underscore the substantial immunodeficiency associated with End-Stage Renal Disease. The persistence of protective antibodies as well as the effect of a booster dose remain to be investigated in HD patients.