Insufficient vaccine coverage and dominance of the more transmissible SARS-Cov-2 variants are the leading causes of the continued spread of COVID-19 worldwide. To curb the surge in infections, COVID-19 vaccination has been advocated as a prioritizing measure especially for frail populations and people at high risk of exposure. Patients on in-center maintenance hemodialysis embody both conditions. They are at high risk of severe COVID-19 consequences due to their advanced age and weakened immune system and carry an increased risk of SARS-CoV-2 transmission within shared dialysis rooms and public vehicles. Vaccination of the entire hemodialysis population is therefore the most effective strategy to protect patients from the dire consequences of COVID-19. Unfortunately, a minority of patients still express COVID-19 vaccine hesitancy. The management of this group of patients, who have the full right to hemodialysis treatment, poses demanding problems from a patient safety perspective. The placement of unvaccinated patients within the dialysis room and the protection of all vaccinated patients are some of the most urgent problems the nephrologist faces during the COVID-19 pandemic. In light of these COVID-19-driven changes, an ethical reflection on the management of unvaccinated patients appears crucial to act responsibly and contribute to the health promotion of dialysis patients.

Clinical application of continuous flow peritoneal dialysis (CFPD) has been explored since the 1960s, but despite anticipated clinical benefits, CFPD has failed to gain a foothold in clinical practice, among others due to the typical use of two catheters (or a dual‐lumen catheter) and large dialysate volumes required per treatment. Novel systems applying CFPD via the existing single‐lumen catheter using rapid dialysate cycling may solve one of these hurdles. Novel on‐demand peritoneal dialysate generation systems and sorbent‐based peritoneal dialysate regeneration systems may considerably reduce the storage space for peritoneal dialysate and/or the required dialysate volume. This review provides an overview of current evidence on CFPD in vivo. The available (pre)clinical evidence on CFPD is limited to case reports/series with inherently nonuniform study procedures, or studies with a small sample size, short follow‐up, and no hard endpoints. Small solute clearance appears to be higher in CFPD compared to conventional PD, in particular at dialysate flows ≥100 mL/min using two single‐lumen catheters or a double‐lumen catheter. Results of CFPD using rapid cycling via a single‐lumen catheter are too preliminary to draw any conclusions. Continuous addition of glucose to dialysate with CFPD appears to be effective in reducing the maximum intraperitoneal glucose concentration while increasing ultrafiltration efficiency (mL/g absorbed glucose). Patient tolerance may be an issue since abdominal discomfort and sterile peritonitis were reported with continuous circulation of the peritoneal dialysate. Thus, well‐designed clinical trials of longer duration and larger sample size, in particular applying CFPD via the existing catheter, are urgently required.

Introduction. Patients receiving in-center hemodialysis are extremely vulnerable to COVID-19. It is unclear if routine screening of asymptomatic hemodialysis patients is an effective strategy to prevent COVID-19 outbreaks within the dialysis unit. Methods. We conducted a retrospective analysis of in-center hemodialysis patients who underwent bimonthly COVID-19 rapid antigen test screening from February 15th to December 26th, 2021. Nasal rapid antigen testing was performed in all asymptomatic patients. All rapid antigen-positive tests were confirmed by RT-PCR nasopharyngeal swab. Besides universal rapid antigen screening, RT-PCR testing was conducted in all symptomatic patients and contacts of COVID-19 subjects. Results. Overall, 4079 rapid antigen tests were performed in 277 hemodialysis patients on chronic hemodialysis with a mean age of 68.4 ± 14.6 years. Thirty-eight (0.9%) rapid antigen tests resulted positive. Only five (13.8%) positive-rapid antigen tests were also positive by RT-PCR testing. During the same period, 219 patients regularly screened by rapid antigen tests bimonthly underwent 442 RT-PCR nasopharyngeal swabs for clinical reasons. RT-PCR testing yielded a positive result in 13 (5.9%) patients. The time elapsed between PCR and the negative-rapid antigen test was 7.7 ± 4.6 days (range 1.8–13.9 days). At the end of the follow-up, 6.4% of the population on in-center hemodialysis contracted COVID-19, and routine rapid antigen tests detected only 5 out of 18 (27.7%) COVID-19 cases. No outbreaks of COVID-19 were identified within the dialysis unit. Conclusion. Bimonthly rapid antigen screening led to the early diagnosis of COVID-19 in less than one-third of cases. The short incubation period of the new SARS-CoV-2 variants makes bimonthly test screening inadequate for an early diagnosis of COVID-19. More frequent tests are probably necessary to improve the utility of COVID-19 nasal rapid antigen test in patients on hemodialysis.

Introduction There are limited data on the effects of COVID-19 on peritoneal dialysis (PD) patients. This study aimed to describe the impact of COVID-19 on the PD population. Methods A monocentric retrospective observational study was conducted on 146 consecutive PD patients followed from January 2020 to March 2022 at the University Hospital of Modena, Italy. Results Twenty-seven (18.4%) PD patients experienced 29 episodes of SARS-CoV-2 infection, corresponding to an incidence rate of 0.16 episodes/patient-year. Median age of COVID-19 patients was 60.4 (interquartile range [IQR] 50.2–66.5) years. In unvaccinated patients (n. 9), COVID-19 was always symptomatic and manifested with fever (100%) and cough (77.7%). COVID-19 caused hospital admission of three (33.3%) patients and two (22.2%) died of septic shock. COVID-19 was symptomatic in 83.3% of vaccinated subjects (n.18) and manifested with fever (61.1%) and cough (55.6%). Hospital admission occurred in 27.8% of the subjects but all were discharged home. Median SARS-CoV-2 shedding was 32 and 26 days in the unvaccinated and vaccinated groups, respectively. At the end of the follow-up, COVID-19 triggered the shift from PD to HD in two subjects without affecting the residual renal function of the remaining patients. Overall, COVID-19 caused an excess death of 22.2%. COVID-19 vaccination refusal accounted for only 1.6% in this cohort of patients. Conclusion COVID-19 incident rate was 0.16 episodes/patient-year in the PD population. About one-third of the patients were hospitalized for severe infection. Fatal outcome occurred in two (7.4%) unvaccinated patients. A low vaccination refusal rate was observed in this population. Supplementary Information The online version contains supplementary material available at 10.1007/s10157-022-02283-0.

Safe and timely discontinuation of quarantine of in-center hemodialysis (HD) patients with a previous SARS-CoV-2 infection is a challenging issue for the nephrological community because current guidelines for ending isolation do not mention dialysis patients. To prevent potentially fatal outbreaks of COVID-19, a cautionary approach has been adopted by most dialysis units. The criteria for ending the isolation in the HD population generally coincide with those recommended for immunocompromised people. Thus, a test-based strategy relying on two consecutive negative reverse transcriptase-polymerase chain reaction (RT-PCR) nasopharyngeal swabs has been adopted to terminate quarantine. This strategy has the disadvantage to prolong isolation as RT-PCR positivity does not equate to SARS-CoV-2 infectivity. Consequentially, prolonged positivity of SARS-CoV-2 results in excessive workload for the HD staff who must face an increasing number of COVID-19 patients requiring isolation. This condition leads also to serious implications for the patients and their households including work productivity loss, postponement of health care appointments and an increased risk of COVID-19 reinfection. To counteract this problem other diagnostic tests should be used to provide the best care to HD patients. Recent results seem to encourage the use of RT-PCR cycle threshold (Ct) values and antigenic tests given their better correlation with cell culture for SARS-CoV-2 than RT-PCR testing. Here, we provide an overview of the current scientific evidence on the tests used to verify the infectiousness of the virus in order to stimulate the nephrological community to adopt a streamlined and pragmatic procedure to end isolation in COVID-19 patients on HD.