Clinical Features of Asymptomatic SARS-CoV-2 Infection in Hemodialysis Patients

Prevalence of Asymptomatic COVID-19 Infection in Hemodialysis Patients and the Risk of Hypercoagulability: Should we Consider Routine Screening?

Introduction

Coronavirus disease 2019 (COVID-19) has become a pandemic in late 2019. Its clinical presentation varies from asymptomatic infection to severe respiratory failure. Infection control strategies to minimize the risk of transmission of COVID-19 in end-stage renal disease (ESRD) patients receiving in-center hemodialysis (HD) have been implemented. Development of humoral response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adult patients with ESRD receiving HD has not been sufficiently reported.

Methods

A total of 179 asymptomatic HD patients undergoing regular HD were screened for COVID-19 infection. Infection with SARS-CoV-2 was confirmed through a real-time reverse transcription polymerase chain reaction assay of nasopharyngeal swab specimens. They were classified into positive and negative groups according to the results of PCR.

Results

Of the 179 asymptomatic patients, we found that 23 patients (12.8%) were positive for COVID-19. Their mean age was 45.61 ± 13.38 years. There was a significant difference between both groups regarding C-reactive protein, lymphocytes, and platelet counts (P < 0.001). Also, TAT (thrombin-antithrombin complex) and D-dimer levels were significantly increased among the positive group (11.47 ± 1.51 vs. 7.53 ± 1.64 mcq/L, P < 0.001; 1171.52 ± 267.6 vs. 542.76 ± 107.06 ng/mL, P < 0.001, respectively).

Conclusion

Asymptomatic SARS-CoV-2 infection is detected in HD patients. They carry the risk of hypercoagulability complications. We need more strict infection control measures and proactive diagnosis to limit the spread of the infection and lethal thromboembolic complications.

Immune Response to Third and Fourth COVID-19 Vaccination in Hemodialysis Patients and Kidney Transplant Recipients

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a serious hazard for hemodialysis (HD) patients and kidney transplant (KTX) recipients as they suffer from an impaired immune response to SARS-CoV-2 vaccination. In addition, a definition of SARS-CoV-2 IgG titer that indicates a sufficient immune response, especially against new omicron variants, is urgently needed. In the present study, the immune response to either a third or a fourth dose of a mRNA vaccine was investigated in 309 dialysis and 36 KTX patients. SARS-CoV-2 IgG titer thresholds indicating neutralizing activity against wild type (WT) and the omicron variant BA.1 were quantified. After four vaccine doses, a high-neutralizing activity against WT was evidenced in HD patients, whereas the neutralizing rate against BA.1 was significant lower. Concerning KTX recipients, humoral and cellular immune responses after a third vaccination were still highly impaired. This calls for modified omicron-targeting vaccines.

Impact of different COVID-19 waves on kidney replacement therapy epidemiology and mortality: REMER 2020

BACKGROUND

Kidney replacement therapy (KRT) confers the highest risk of death from coronavirus disease 2019 (COVID-19). However, most data refer to the early pandemic waves. Whole-year analysis compared with prior secular trends are scarce.

METHODS

We present the 2020 REMER Madrid KRT registry, corresponding to the Spanish Region hardest hit by COVID-19.

RESULTS

In 2020, KRT incidence decreased 12% versus 2019, while KRT prevalence decreased by 1.75% for the first time since records began and the number of kidney transplants (KTs) decreased by 16%. Mortality on KRT was 10.2% (34% higher than the mean for 2008-2019). The 2019-2020 increase in mortality was larger for KTs (+68%) than for haemodialysis (+24%) or peritoneal dialysis (+38%). The most common cause of death was infection [n = 419 (48% of deaths)], followed by cardiovascular [n = 200 (23%)]. Deaths from infection increased by 167% year over year and accounted for 95% of excess deaths in 2020 over 2019. COVID-19 was the most common cause of death (68% of infection deaths, 33% of total deaths). The bulk of COVID-19 deaths [209/285 (73%)] occurred during the first COVID-19 wave, which roughly accounted for the increased mortality in 2020. Being a KT recipient was an independent risk factor for COVID-19 death.

CONCLUSIONS

COVID-19 negatively impacted the incidence and prevalence of KRT, but the increase in KRT deaths was localized to the first wave of the pandemic. The increased annual mortality argues against COVID-19 accelerating the death of patients with short life expectancy and the temporal pattern of COVID-19 mortality suggests that appropriate healthcare may improve outcomes.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: Update of a living systematic review and meta-analysis

BACKGROUND

Debate about the level of asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection continues. The amount of evidence is increasing and study designs have changed over time. We updated a living systematic review to address 3 questions: (1) Among people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) What is the infectiousness of asymptomatic and presymptomatic, compared with symptomatic, SARS-CoV-2 infection? (3) What proportion of SARS-CoV-2 transmission in a population is accounted for by people who are asymptomatic or presymptomatic?

METHODS AND FINDINGS

The protocol was first published on 1 April 2020 and last updated on 18 June 2021. We searched PubMed, Embase, bioRxiv, and medRxiv, aggregated in a database of SARS-CoV-2 literature, most recently on 6 July 2021. Studies of people with PCR-diagnosed SARS-CoV-2, which documented symptom status at the beginning and end of follow-up, or mathematical modelling studies were included. Studies restricted to people already diagnosed, of single individuals or families, or without sufficient follow-up were excluded. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with a bespoke checklist and modelling studies with a published checklist. All data syntheses were done using random effects models. Review question (1): We included 130 studies. Heterogeneity was high so we did not estimate a mean proportion of asymptomatic infections overall (interquartile range (IQR) 14% to 50%, prediction interval 2% to 90%), or in 84 studies based on screening of defined populations (IQR 20% to 65%, prediction interval 4% to 94%). In 46 studies based on contact or outbreak investigations, the summary proportion asymptomatic was 19% (95% confidence interval (CI) 15% to 25%, prediction interval 2% to 70%). (2) The secondary attack rate in contacts of people with asymptomatic infection compared with symptomatic infection was 0.32 (95% CI 0.16 to 0.64, prediction interval 0.11 to 0.95, 8 studies). (3) In 13 modelling studies fit to data, the proportion of all SARS-CoV-2 transmission from presymptomatic individuals was higher than from asymptomatic individuals. Limitations of the evidence include high heterogeneity and high risks of selection and information bias in studies that were not designed to measure persistently asymptomatic infection, and limited information about variants of concern or in people who have been vaccinated.

CONCLUSIONS

Based on studies published up to July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. Summary estimates from meta-analysis may be misleading when variability between studies is extreme and prediction intervals should be presented. Future studies should determine the asymptomatic proportion of SARS-CoV-2 infections caused by variants of concern and in people with immunity following vaccination or previous infection. Without prospective longitudinal studies with methods that minimise selection and measurement biases, further updates with the study types included in this living systematic review are unlikely to be able to provide a reliable summary estimate of the proportion of asymptomatic infections caused by SARS-CoV-2.

REVIEW PROTOCOL

Open Science Framework (https://osf.io/9ewys/).

OUP accepted manuscript

Background

Kidney replacement therapy (KRT) conferred a high risk for coronavirus disease 2019 (COVID-19) related mortality early in the pandemic. We evaluate the presentation, treatment and outcomes of COVID-19 in patients on KRT over time during the pandemic.

Methods

This registry-based study involved 6080 dialysis and kidney transplant (KT) patients with COVID-19, representing roughly 10% of total Spanish KRT patients. Epidemiology, comorbidity, infection, vaccine status and treatment data were recorded, and predictors of hospital admission, intensive care unit (ICU) admission and mortality were evaluated.

Results

Vaccine introduction decreased the number of COVID-19 cases from 1747 to 280 per wave. Of 3856 (64%) COVID-19 KRT patients admitted to the hospital, 1481/3856 (38%) were admitted during the first of six waves. Independent predictors for admission included KT and the first wave. During follow-up, 1207 patients (21%) died, 500/1207 (41%) during the first wave. Among vaccinated patients, mortality was 19%, mostly affecting KT recipients. Overall, independent predictors for mortality were older age, disease severity (lymphopaenia, pneumonia) and ICU rejection. Among patient factors, older age, male sex, diabetes, KT and no angiotensin receptor blockers (ARB) were independent predictors of death. In KT recipients, individual immunosuppressants were independent predictors of death. Over time, patient characteristics evolved and in later pandemic waves, COVID-19 was mainly diagnosed in vaccinated KT recipients; in the few unvaccinated dialysis patients, ICU admissions increased and mortality decreased (28% for the first wave and 16–22% thereafter).

Conclusions

The clinical presentation and outcomes of COVID-19 during the first wave no longer represent COVID-19 in KRT patients, as the pandemic has become centred around vaccinated KT recipients. Vaccines lowered the incidence of diagnosed COVID-19 and mortality. However, mortality remains high despite increased access to ICU care.

COVID-19 en el paciente en diálisis. Una revisión sistemática

Introducción: La pandemia por COVID-19 acaecida en 2019 afectó con mayor gravedad a la población de mayor edad y con enfermedades subyacentes, siendo estos factores de riesgo de mortalidad. Estas características son propias del paciente renal en diálisis, por lo que es importante conocer cuál fue el impacto del COVID-19 en este grupo poblacional.Objetivo: El objetivo principal fue conocer y sintetizar la evidencia científica existente sobre las características clínicas de la enfermedad COVID-19 en el paciente con enfermedad renal crónica en diálisis.Metodología: Se realizó una revisión sistemática basada en la declaración PRISMA, en la que se analizaron 23 artículos procedentes de las bases de datos PubMed y Scopus. Se incluyeron artículos originales en inglés y español que excluyeran la población pediátrica.Resultados: Se incluyeron 23 artículos de diseño observacional. Principalmente los resultados se centraron en incidencia, características clínicas, como sintomatología o evolución, mortalidad y medidas preventivas en las unidades de diálisis.Conclusiones: La incidencia de la COVID-19 fue mayor en unidades de diálisis que en los pacientes que recibían diálisis domiciliaria. La sintomatología más leve fue la común a la población general. En los casos más graves, cerca del 50% de los pacientes necesitaron hospitalización y/o ingreso en una Unidad de Cuidados Intensivos. La mortalidad fue bastante elevada y se relacionó con la edad avanzada, comorbilidad, sexo masculino o fragilidad clínica. Además, en las unidades de diálisis se implementaron medidas de prevención de la enfermedad, al ser espacios físicos cerrados donde se concentra un gran número de pacientes.

Study on Ultrasonic Imaging of Nursing Care for Preventing and Treating Clinical Infection of Hemodialysis Patients Based on Smart Medical Big Data

The ultrasonic imaging research of nursing care for preventing and treating clinical infection of hemodialysis patients based on smart medical big data is studied. 100 hemodialysis patients were selected from May 2019 to May 2020. The patients were randomly divided into the observation group and routine group with 50 cases in each group. The PWV of common carotid artery was measured by ultrasonic rapid imaging technology, including BS value at the beginning of systole and ES value at the end of systole. According to the effect of preventive nursing intervention of intelligent medical treatment, the MHD group adopted preventive nursing intervention, while the routine group adopted traditional nursing service. The infection rate and quality of life score of patients in both groups were evaluated. The results showed that there were significant differences in BS and ES values between the MHD group and PWV in the normal group (P < 0.05). There was no significant difference in BS value and ES value between MHD patients with plaque and those without plaque (P > 0.05). It is proved that the ultrafast ultrasound imaging technology is safe, simple, noninvasive, nonradioactive, and fast and can automatically and accurately detect carotid PWV. It is expected to become a new imaging method for quantitative evaluation of arteriosclerosis degree in MHD patients. Preventive nursing intervention can reduce the incidence of infection in hemodialysis patients and improve their quality of life. Smart medical treatment has brought us a lot of convenience. As patients, we should change our concept, actively participate in it, and contribute to the development of smart medical treatment.

Immune Responses to SARS-CoV-2 Infection and Vaccination in Dialysis Patients and Kidney Transplant Recipients

Dialysis patients and kidney transplant (KTX) recipients suffer from an impaired immune system and show a decreased response to the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) vaccination. We performed a retrospective analysis of 1505 serological SARS-CoV-2 measurements obtained from 887 dialysis patients and 86 KTX recipients. The results were separated by patient subgroups (dialysis/KTX) as well as SARS-CoV-2 status. The latter criterion included SARS-CoV-2-naïve patients with or without COVID-19 vaccination and convalescent patients receiving a booster shot. Serologies of 27 vaccinated healthy individuals served as the reference group. Vaccine-induced cellular immune response was quantified by an interferon-γ release assay in 32 KTX recipients. We determined seroconversion rates of 92.6%, 93.4%, and 71.4% in dialysis patients vaccinated with either BNT162b2, mRNA-1273, or AZD1222, respectively. Vaccination-induced anti-SARS-CoV-2 antibody titers were lower in dialysis patients compared to healthy individuals, and vaccination with mRNA-1273 induced higher titers than BNT162b2. The initial seroconversion rate was 39.5% in KTX recipients vaccinated with BNT162b2. A linear regression model identified medication with mycophenolate-mofetil/mycophenolic acid as an independent risk factor for missing seroconversion. Within a cohort of 32 KTX recipients, cellular and humoral immune reactivity to SARS-CoV-2 was detectable in three patients only. Conclusively, vaccine-induced seroconversion rates were similar in dialysis patients compared to healthy individuals but were strongly impaired in KTX recipients. Anti-SARS-CoV-2 IgG titers elicited by double active immunization were significantly lower in both cohorts compared to healthy individuals, and immune responses to vaccination vanished quickly.

Explaining the unexpected COVID-19 trends and potential impact across Africa

Official COVID-19 case counts and mortality rates across Africa are lower than had been anticipated. Research reports, however, indicate far higher exposure rates than the official counts in some countries. Particularly in Western and Central Africa, where mortality rates are disproportionately lower than the rest of the continent, this occurrence may be due to immune response adaptations resulting from (1) frequent exposure to certain pro-inflammatory pathogens, and (2) a prevalence of low-grade inflammation coupled with peculiar modifications to the immune response based on one's immunobiography. We suggest that the two factors lead to a situation where post infection, there is a rapid ramp-up of innate immune responses, enough to induce effective defense and protection against plethora pathogens. Alongside current efforts at procuring and distributing vaccines, we draw attention to the need for work towards appreciating the impact of the apparently widespread, asymptomatic SARS-CoV-2 infections on Africa's populations vis a vis systemic inflammation status and long-term consequences for public health.

Explaining the unexpected COVID-19 trends and potential impact across Africa

Official COVID-19 case counts and mortality rates across Africa are lower than had been anticipated. Research reports, however, indicate far higher exposure rates than the official counts in some countries. Particularly in Western and Central Africa, where mortality rates are disproportionately lower than the rest of the continent, this occurrence may be due to immune response adaptations resulting from (1) frequent exposure to certain pro-inflammatory pathogens, and (2) a prevalence of low-grade inflammation coupled with peculiar modifications to the immune response based on one's immunobiography. We suggest that the two factors lead to a situation where post infection, there is a rapid ramp-up of innate immune responses, enough to induce effective defense and protection against plethora pathogens. Alongside current efforts at procuring and distributing vaccines, we draw attention to the need for work towards appreciating the impact of the apparently widespread, asymptomatic SARS-CoV-2 infections on Africa's populations vis a vis systemic inflammation status and long-term consequences for public health.

The frail world of haemodialysis patients in the COVID-19 pandemic era: a systematic scoping review

BACKGROUND

Patients undergoing in-centre haemodialysis (HD) are particularly exposed to the dire consequences of COVID-19. The present systematic scoping review aims to identify the extent, range, and nature of articles related to COVID-19 and maintenance HD: it reports specifically the prevalence of the COVID-19 pandemic in the HD population, implementation of strategies for the prevention, mitigation and containment of the COVID-19 pandemic in HD centres, demographic and clinical characteristics, and outcomes of the pediatric and adult HD patients.

METHODS

A multi-step systematic search of the literature in Pubmed, Scopus, Ovid Medline, Embase and Web of Science, published between December 1, 2019, and January 30, 2021 was performed. Two authors separately screened the titles and abstracts of the documents and ruled out irrelevant articles. A report of the papers that met inclusion criteria was performed; then, a descriptive analysis of the characteristics of the included articles and a narrative synthesis of the results were performed.

RESULTS

The review process ended with the inclusion of 145 articles. Most of them were based on single-centre experiences, which spontaneously developed best practices. Most studies were conducted in high-income countries (69.7%) and a part of them (9.6%) were not in English. Prevalence of COVID-19 among dialysis patients accounted for 0%-37.6%. Preventive measures were reported in 54% of the included articles, with particular emphasis on education, triage, hygiene, and containment measures. Patients experienced a heterogeneous spectrum of symptoms that led 35%-88.2% of them to hospital admission. Median and mean hospital length of stay ranged from 8 to 28.5 and 16.2 to 22 days, respectively. Admission to intensive care units varied widely across studies (from 2.6% to 70.5%) and was associated with high mortality (42.8%-100%). Overall, prognosis was poor in 0%-47% of the hospitalized patients.

CONCLUSIONS

This systematic scoping review provides an overview of the current knowledge on the impact of COVID-19 on the frail world of HD patients. Furthermore, it may help to implement the existing strategies of COVID-19 prevention and provide a list of unmet needs (safe transport, testing, shelter). Finally, it may be a stimulus for performing systematic reviews and meta-analyses which will form the basis for evidence-based guidelines.