Kinetics of Anti-SARS-CoV-2 IgG Antibodies in Hemodialysis Patients Six Months after Infection

The Mathematical Modeling of the Host-Virus Interaction in Dengue Virus Infection: A Quantitative Study

Infectious diseases, such as Dengue fever, pose a significant public health threat. Developing a reliable mathematical model plays a crucial role in quantitatively elucidating the kinetic characteristics of antibody-virus interactions. By integrating previous models and incorporating the antibody dynamic theory, we have constructed a novel and robust model that can accurately simulate the dynamics of antibodies and viruses based on a comprehensive understanding of immunology principles. It explicitly formulates the viral clearance effect of antibodies, along with the positive feedback stimulation of virus-antibody complexes on antibody regeneration. In addition to providing quantitative insights into the dynamics of antibodies and viruses, the model exhibits a high degree of accuracy in capturing the kinetics of viruses and antibodies in Dengue fever patients. This model offers a valuable solution to modeling the differences between primary and secondary Dengue infections concerning IgM/IgG antibodies. Furthermore, it demonstrates that a faster removal rate of antibody-virus complexes might lead to a higher peak viral loading and worse clinical symptom. Moreover, it provides a reasonable explanation for the antibody-dependent enhancement of heterogeneous Dengue infections. Ultimately, this model serves as a foundation for constructing an optimal mathematical model to combat various infectious diseases in the future.

COVID-19 vaccine in hemodialysis patients: Time for a boost

OBJECTIVES

To evaluate anti-spike immunoglobulin G (IgG) antibody levels of hemodialysis patients and correlate them with the patients' demographic data and to evaluate these patients' need for a coronavirus disease-19 (COVID-19) vaccine booster.

METHODS

A cross-sectional multi-center study carried out at King Abdulaziz Kidney Center, Hasan Tahir Hemodialysis Center, and Hayat Organization Hemodialysis Center in Al-Madinah Al-Munawarah, Saudi Arabia. Patients (n=167) who received a minimum single dose of COVID-19 vaccine were recruited. The samples were collected between March 2022 and January 2023. Anti-spike IgG antibody levels were measured using enzyme-linked immunosorbent assays.

RESULTS

A significantly higher proportion of patients who received 3 doses of COVID-19 vaccine had positive serostatus compared with patients who received one or 2 doses (3 doses: 87.2%, one dose: 0.0%, 2 doses: 77.3%; p=0.000). Compared with patients who received one dose, significantly higher IgG antibody levels were detected in patients who received 2 (p=0.013) and 3 doses (p=0.025; n=35). In contrast, there was no significant difference in IgG antibody levels between patients who received 2 or 3 doses (p=0.45). Significant IgG antibody levels were detected in patients who received 2 and 3 doses (p=0.0125) compared with those received one vaccine dose (p=0.0004). Furthermore, patients who received 3 doses had significantly higher IgG antibody levels than patients who received 2 doses (p=0.000).

CONCLUSION

The results show a dose-dependent association between IgG antibody levels and the number COVID-19 vaccines received. The study highlights the need for booster COVID-19 vaccination for patients on hemodialysis.

COVID-19 Vaccine Antibody Response in a Single-Center Urban Hemodialysis Unit

BACKGROUND

The longitudinal response to the COVID-19 vaccines among patients on hemodialysis with and without prior SARS-CoV-2 infection has not been well characterized.

METHODS

To guide vaccination strategies in patients on hemodialysis, it is critical to characterize the longevity and efficacy of the vaccine; therefore, we conducted a prospective single-center monthly antibody surveillance study between March 2021 and March 2022 to investigate the dynamic humoral response to a series of COVID-19 mRNA vaccines in patients on hemodialysis with and without prior SARS-CoV-2 infection. Monthly quantitative antibody testing was performed using the Beckman Coulter Access SARS-CoV-2 IgG Antibody Test©, which detects IgG antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 spike protein.

RESULTS

This cohort of 30 participants (mean age: 61 ± 3 years) predominantly self-identified as African American (97%) and male (53%). Eight participants (27%) had recovered from COVID-19 (recovered) before the vaccine initiation. All participants received two vaccine doses, and 86.6% received a 6-month booster dose. Among patients naïve to COVID-19, the antibody positivity rate (APR) was 55% post-first-dose, 91% post-second-dose, 50% pre-booster at 6 months, 100% post-booster, and 89% at 6 months post-booster. Recovered patients sustained a consistent 100% APR throughout the year. The naïve patients demonstrated lower peak antibody levels post-second-dose than the recovered patients (17.9 ± 3.2 vs. 44.7 ± 5.6, p < 0.001). The peak antibody levels post-booster showed no significant difference between both groups (27.1 ± 3.9 vs. 37.9 ± 8.2, p = 0.20). Two naïve patients contracted COVID-19 during the follow-up period.

CONCLUSIONS

The patients naïve to COVID-19 exhibited an attenuated and foreshortened antibody response following two doses of the mRNA vaccines compared with the recovered patients, who maintained 100% APR before the booster dose. The 6-month booster dose counteracted declining immunity and stimulated antibody responses in the naïve patients, even in previously non-responsive patients. This observation implies that different booster vaccination strategies might be required for COVID-19-naïve and -recovered patients. Post-vaccination antibody testing may serve as a valuable tool for guiding vaccination strategies.

Long-term evaluation of the seroprevalence of SARS-CoV-2 IgG and IgM antibodies in recovered patients: a meta-analysis

Estimating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) -specific immunoglobulin G (IgG) immunoglobulin M (IgM) antibodies are increasingly important for tracking the spread of infection and defining herd immunity barrier and individual immunization levels in the ongoing coronavirus disease 2019 (COVID-19) pandemic. Therefore, we conducted the present systematic review and meta-analysis to evaluate the seroprevalence of SARS-CoV-2 IgM and IgG antibodies of recovered COVID-19 patients in long-term follow-up studies. A systematic search of the MEDLINE, Embase, COVID-19 Primer, PubMed, CNKI, and the Public Health England library databases was conducted. Twenty-fourth eligible studies were included. Meta-analysis showed that 27% (95%CI: 0.04-0.49) and 66% (95%CI:0.47-0.85) were seropositive for SARS-CoV-2 IgM and IgG, respectively, while in long-term 12 months following up studies, the seroprevalences of IgM antibody (17%) decreased and IgG antibody (75%) was higher than 6 months follow-up patients. However, due to the limited number of relevant studies, the high level of heterogeneity, and the large gap in studies conducted, the findings of our study may not accurately reflect the true seroprevalence status of SARS-CoV-2 infection. Nevertheless, sequential vaccination or booster immunization is considered to be a necessary long-term strategy to sustain the fight against the pandemic.

Primary SARS-CoV-2 infection in patients with immune-mediated inflammatory diseases: long-term humoral immune responses and effects on disease activity

BACKGROUND

Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressants (ISPs) may have impaired long-term humoral immune responses and increased disease activity after SARS-CoV-2 infection. We aimed to investigate long-term humoral immune responses against SARS-CoV-2 and increased disease activity after a primary SARS-CoV-2 infection in unvaccinated IMID patients on ISPs.

METHODS

IMID patients on active treatment with ISPs and controls (i.e. IMID patients not on ISP and healthy controls) with a confirmed SARS-CoV-2 infection before first vaccination were included from an ongoing prospective cohort study (T2B! study). Clinical data on infections and increased disease activity were registered using electronic surveys and health records. A serum sample was collected before first vaccination to measure SARS-CoV-2 anti-receptor-binding domain (RBD) antibodies.

RESULTS

In total, 193 IMID patients on ISP and 113 controls were included. Serum samples from 185 participants were available, with a median time of 173 days between infection and sample collection. The rate of seropositive IMID patients on ISPs was 78% compared to 100% in controls (p < 0.001). Seropositivity rates were lowest in patients on anti-CD20 (40.0%) and anti-tumor necrosis factor (TNF) agents (60.5%), as compared to other ISPs (p < 0.001 and p < 0.001, respectively). Increased disease activity after infection was reported by 68 of 260 patients (26.2%; 95% CI 21.2-31.8%), leading to ISP intensification in 6 out of these 68 patients (8.8%).

CONCLUSION

IMID patients using ISPs showed reduced long-term humoral immune responses after primary SARS-CoV-2 infection, which was mainly attributed to treatment with anti-CD20 and anti-TNF agents. Increased disease activity after SARS-CoV-2 infection was reported commonly, but was mostly mild.

TRIAL REGISTRATION

NL74974.018.20, Trial ID: NL8900. Registered on 9 September 2020.

COVID-19 in Elderly Patients Receiving Haemodialysis: A Current Review

There is an increased incidence of elderly adults diagnosed with kidney failure as our global aging population continues to expand. Hence, the number of elderly adults indicated for kidney replacement therapy is also increasing simultaneously. Haemodialysis initiation is more commonly observed in comparison to kidney transplantation and peritoneal dialysis for the elderly. The onset of the coronavirus 2019 (COVID-19) pandemic brought new paradigms and insights for the care of this patient population. Elderly patients receiving haemodialysis have been identified as high-risk groups for poor COVID-19 outcomes. Age, immunosenescence, impaired response to COVID-19 vaccination, increased exposure to sources of COVID-19 infection and thrombotic risks during dialysis are key factors which demonstrated significant associations with COVID-19 incidence, severity and mortality for this patient group. Recent findings suggest that preventative measures such as regular screening and, if needed, isolation in COVID-19-positive cases, alongside the fulfillment of COVID-19 vaccination programs is an integral strategy to reduce the number of COVID-19 cases and consequential complications from COVID-19, particularly for high-risk groups such as elderly haemodialysis patients. The COVID-19 pandemic brought about the rapid development and repurposing of a number of medications to treat patients in the viral and inflammatory stages of their disease. However, elderly haemodialysis patients were grossly unrepresented in many of these trials. We review the evidence for contemporary treatments for COVID-19 in this population to provide clinicians with an up-to-date guide. We hope our article increases awareness on the associations and impact of COVID-19 for the elderly haemodialysis population, and encourage research efforts to address knowledge gaps in this topical area.

Waning Humoral Response 6 Month after Double Vaccination with the mRNA-BNT162b2 Vaccine in Hemodialysis Patients

Introduction

Although most hemodialysis patients (HDP) exhibit an initial seroresponse to vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), studies have shown this response to be lower compared to healthy subjects. This fact raised concerns regarding the durability of the immune response and effective protection against severe Coronavirus disease 2019 (COVID-19) in this vulnerable population. The aim of our study was to evaluate the change in antibody levels over time in HDP population.

Materials and Methods

We performed a prospective multicenter study, evaluating antibody response among HDP at 2 and at 6 months after complete two-dose vaccination course with the mRNA-BNT162b2 (Pfizer-BioNTech) vaccine. The study was performed in 14 hemodialysis units of a private dialysis provider in Lithuania. The serum samples of 189 HDP were tested for SARS-CoV-2 IgG against the Spike glycoprotein.

Results

189 HDP participated in the study. Patients were 64.3±15.7 years of age, 116 (61.4%) were males and 73 (38.6%) were females. Among them, 183 (96.8%) were seropositive for anti-S IgG at 2 months after the second immunization dose. Six months after the second dose only 145 (76.7%) of study participants had positive anti-S IgG titers. The median level of anti-S IgG titers after 2 months was 383.1 BAU/mL (166.2-995.6) and after 6 months this level significantly decreased to 51.4 BAU/mL (22.0-104.0) (p<0.001). Seroresponses at both time points inversely correlated with increasing patient's age. Risk factor for absent response after 2 months included oncologic disease. Systemic autoimmune disease and a history of myocardial infarction increased risk to be seronegative 6 months after the second vaccine dose.

Conclusions

The majority of hemodialysis patients seroresponded after BNT162b2/Pfizer vaccination, but vaccine-induced humoral immunity wanes over time.

Kinetics of SARS-CoV-2 IgM and IgG Antibodies 3 Months after COVID-19 Onset in Moroccan Patients

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses serious global public health problems. Characterization of the immune response, particularly antibodies to SARS-CoV-2, is important for establishing vaccine strategies. The purpose of this study was to evaluate longitudinally the kinetics of anti-SARS-CoV-2 antibodies against spike protein (S1) for up to 3 months in a cohort of 169 COVID-19 patients. We enrolled COVID-19 patients at two regional hospitals in Casablanca, Morocco, between March and September 2021. Blood samples were collected and N-specific IgM and S-specific IgG levels were measured by a commercial Euroimmun ELISA. IgM antibodies were assessed 2-5 (D00), 9-12 (D07), 17-20 (D15), and 32-37 (D30) days after symptom onset; IgG antibodies were assessed at these time points plus 60 (D60) and 90 (D90) days after symptom onset. We found that at 3 months after symptom onset, 79% of patients had detectable SARS-CoV-2-specific IgG antibodies, whereas their IgM seropositivity was 19% by 1 month after symptom onset. The IgM level decreased to 0.34 (interquartile range [IQR] 0.19-0.92) at 1 month after symptom onset, whereas the IgG level peaked at D30 (3.10; IQR 1.83-5.64) and remained almost stable at D90 (2.95; IQR 1.52-5.19). IgG levels were significantly higher in patients older than 50 years than in those younger than 50 at all follow-up time points (P < 0.05). Statistical analysis showed no significant difference in median anti-S1 antibody levels among infected patients based on gender or comorbidities. This study provides information on the longevity of anti-SARS-CoV-2 IgM and IgG antibodies in COVID-19 patients.

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.

Presence of specific SARS-COV2 antibodies in hemodialysis patients and their caregivers after the first wave of COVID-19

Hemodialysis (HD) patients are at risk for severe COVID-19 and cannot comply with social distancing. SARS-COV2 seroprevalence in French patients and caregivers after the first wave of COVID-19 is unknown. SeroCOVIDial is a prospective study conducted between June and December 2020. SARS-COV2 seroprevalence was evaluated by a rapid serological test (BIOSYNEX) in HD patients and caregivers, and the presence or not of anti-SARS-COV2 neutralizing or non-neutralizing antibodies in patients was also determined by ELISA and seroneutralization. In June 2020, 451 HD patients and 238 caregivers were included. Overall SARS-COV2 seroprevalence was 8.4% (patients) and 6.7% (caregivers), and was 87.1% (patients) and 90.0% (caregivers) in participants with a previously documented SARS-COV2 infection. Overall seroprevalence reached 13.8% (patients) and 12.6% (caregivers) following the second epidemic wave. During the follow-up, 38 (8.4%) patients died (9 of COVID-19). Among the 44 (10.6%) patients who became infected, only two were seropositive at M0. The levels of anti-SARS-COV2 antibodies decreased over time in patients and caregivers. The BIOSYNEX test showed 82.9% sensitivity and 97.7% specificity. Prevalence of anti-SARS-COV2 antibodies was low in HD patients and caregivers after the first epidemic wave but rose after the second wave. A rapid serological test showed good performances and could be useful for future monitoring of anti-SARS-COV2 antibodies.

Prevalence of anti-SARS-CoV-2 antibody in hemodialysis facilities: a cross-sectional multicenter study from Madinah

BACKGROUND

Since the occurrence of coronavirus disease in 2019 (COVID-19), the global community has witnessed its exponential spread with devastating outcomes within the general population and specifically within hemodialysis patients.

OBJECTIVES

Compare the state of immunity to SARS-CoV-2 among hemodialysis patients and staff.

DESIGN

Cross-sectional study with a prospective follow-up period.

SETTING

Hemodialysis centers in Madinah region.

PATIENTS AND METHODS

We prospectively tested for SARS-CoV-2 antibodies in dialysis patients using dialysis centers staff as controls. The participants were tested on four occasions when feasible for the presence of anti-SARS-CoV-2 antibodies. We also analyzed factors that might be associated with seropositivity.

MAIN OUTCOME MEASURES

SARS-CoV-2 positivity using immunoglobulin G (IgG) levels SAMPLE SIZE: 830 participants, 677 patients and 153 dialysis centers staff as controls.

RESULTS

Of the total participants, 325 (257 patients and 68 staff) were positive for SARS-CoV-2 IgG antibodies, for a prevalence of 38.0% and 44.4% among patients and staff, respectively (P=.1379). Participants with a history of COVID-19 or related symptoms were more likely to have positive IgG (P<.0001). Surprisingly, positivity was also center-dependent. In a multivariable logistic regression, a history of infection and related symptoms contributed significantly to developing immunity.

CONCLUSION

The high prevalence of SARS-CoV-2 antibody among hemodialysis patients and previously asymptomatic staff suggested past asymptomatic infection. Some centers showed more immunity effects than others.

LIMITATIONS

Unable to collect four samples for each participant; limited to one urban center.

CONFLICT OF INTEREST

None.

COVID-19 in dialysis: clinical impact, immune response, prevention, and treatment

The COVID-19 pandemic has profound adverse effects on the population on dialysis. Patients requiring dialysis are at an increased risk of SARS-CoV-2 infection and mortality, and many have experienced psychological distress as well as delayed or suboptimal care. COVID-19 survivors have prolonged viral shedding, but generally develop a robust and long-lasting humoral immune response that correlates with initial disease severity. However, protection against reinfection is incomplete. A growing body of evidence reveals delayed and blunted immune responses to SARS-CoV-2 vaccination. Administration of a third dose within 1 to 2 months of prime-boost vaccination significantly increases antibody levels, in particular in patients with poor initial responses. Patients on dialysis have inferior immune responses to adenoviral vector vaccines than to mRNA vaccines. The immunogenicity of the mRNA-1273 vaccine is markedly better than that of the BNT162b2 vaccine, most likely by virtue of its higher mRNA content. Despite suboptimal immune responses in patients on dialysis, preliminary data suggest that vaccination partially protects against infection and severe disease requiring hospitalization. However, progressive waning of immunity and emergence of SARS-CoV-2 variants with a high potential of immune escape call for a booster dose in all patients on dialysis 4 to 6 months after prime-boost vaccination. Patients with persistent poor vaccine responses may be candidates for primary prophylaxis strategies. In the absence of specific data in patients on dialysis, therapeutic strategies in the event of established COVID-19 must be extrapolated from evidence obtained in the population not on dialysis. Neutralizing monoclonal antibodies may be an attractive option after a high-risk exposure or during the early course of infection.

Diminished Short- and Long-Term Antibody Response after SARS-CoV-2 Vaccination in Hemodialysis Patients

Short-term studies have shown an attenuated immune response in hemodialysis patients after COVID-19-vaccination. The present study examines how antibody response is maintained after vaccination against SARS-CoV-2 in a large population of hemodialysis patients from six outpatient dialysis centers. We retrospectively assessed serum antibody levels against SARS-CoV-2 spike protein and nucleocapsid protein (electrochemiluminescence immunoassays, Roche Diagnostics) after COVID-19-vaccination in 298 hemodialysis and 103 non-dialysis patients (controls), comparing early and late antibody response. Compared to a non-dialysis cohort hemodialysis patients showed a favorable but profoundly lower early antibody response, which decreased substantially during follow-up measurement (median 6 months after vaccination). Significantly more hemodialysis patients had anti-SARS-CoV-2-S antibody titers below 100 U/mL (p < 0.001), which increased during follow-up from 23% to 45% but remained low in the control group (3% vs. 7%). In multivariate analysis, previous COVID-19 infections (p < 0.001) and female gender (p < 0.05) were significantly associated with higher early as well as late antibody vaccine response in hemodialysis patients, while there was a significant inverse correlation between patient age and systemic immunosuppression (p < 0.001). The early and late antibody responses were significantly higher in patients receiving vaccination after a SARS-CoV-2 infection compared to uninfected patients in both groups (p < 0.05). We also note that a higher titer after complete immunization positively affected late antibody response. The observation, that hemodialysis patients showed a significantly stronger decline of SARS-CoV-2 vaccination antibody titers within 6 months, compared to controls, supports the need for booster vaccinations to foster a stronger and more persistent antibody response.

Immunogenicity and Safety of COVID-19 Vaccines in Patients Receiving Renal Replacement Therapy: A Systematic Review and Meta-Analysis

Background

Systematic data on the efficacy and safety of COVID-19 vaccine in patients on renal replacement therapy (RRT) remains limited. We conducted a meta-analysis on the efficacy and safety of COVID-19 vaccine in patients on RRT.

Methods

Eligible studies were identified by systematic literature search in four electronic databases. Twenty-seven studies (4,264 patients) were included for meta-analysis. 99% patients received mRNA vaccine.

Results

Patients on RRT showed inferior seropositivity after two-dosed COVID-19 vaccine, 44% lower than the general population. Kidney transplant recipients (KTRs) had significantly lower seropositivity than patients on haemodialysis (HD) or peritoneal dialysis (PD) (26.1 vs. 84.3% and 92.4% respectively, p < 0.001 for both). Compared with healthy controls, KTRs, HD and PD patients were 80% (95% CI: 62–99%), 18% (95% CI: 9–27%) and 11% (95% CI: 1–21%) less likely to develop antibodies after vaccination (p < 0.001, <0.001 and 0.39 respectively). In KTRs, every 1% increase in using mycophenolate was associated with 0.92% reduction in seropositivity (95% CI: −1.68, −0.17, p = 0.021) at population level. The overall adverse event rate attributed to vaccination was 2.1%. Most events were mild.

Conclusion

Patients on RRT, particularly KTRs, had significantly reduced antibody response after two-dosed COVID-19 vaccination. Vaccination is generally well tolerated.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021261879.

Anti-SARS-CoV-2 Antibody Responses 5 Months Post Complete Vaccination of Moroccan Healthcare Workers

Data about the duration of antibodies after vaccination show that the protection against SARS-CoV-2 infection begins to decline over time. This study aims to determine anti-SARS-CoV-2 anti-S IgG levels in healthcare workers five months after the second vaccination dose. We collected samples from 82 participants who were fully vaccinated with ChAdOx1 nCoV-19 or BBIBP-CorV. We assessed anti-SARS-CoV-2 IgG antibodies using a Euroimmun ELISA and an Abbott Architect ™ SARS-CoV-2 IgG test. Of the 82 participants, 65.85% were seropositive for IgG using ELISA, and 86.59% were positive for IgG according to the Abbott Architect ™ test. Individuals vaccinated with the ChAdOx1 nCoV-19 vaccine had a median anti-S1 antibody level of 1.810 AU/mL [interquartile range (IQR), 1.080-3.7340] and 171.7 AU/mL [79.9-684.6] according to the Euroimmun ELISA and Abbott Architect test, respectively. These tests indicated that people vaccinated with BBIBP-CorV had a median anti-S1 antibody level of 1.840 AU/mL [0.810-2.960] and 126.7 AU/mL [54.9-474.3], respectively. Statistical analysis showed no significant difference between the positivity rates of the vaccinated individuals, either for gender or for age. In addition, we found no significant difference between the two vaccines. Our study provides information on the longevity of the anti-SARS-CoV-2 IgG antibodies in people at least five months after vaccination.

Increased 1-year mortality in haemodialysis patients with COVID-19: a prospective, observational study

BACKGROUND

Dialysis confers the highest risk of coronavirus disease 2019 (COVID-19) death among comorbidities predisposing to severe COVID-19. However, reports of COVID-19-associated mortality frequently refer to mortality during the initial hospitalization or first month after diagnosis.

METHODS

In a prospective, observational study, we analysed the long-term (1-year follow-up) serological and clinical outcomes of 56 haemodialysis (HD) patients who were infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the first pandemic wave. COVID-19 was diagnosed by a positive polymerase chain reaction (PCR) test (n = 37) or by the development of anti-SARS-CoV-2 antibodies (n = 19).

RESULTS

After >1 year of follow-up, 35.7% of HD patients infected by SARS-CoV-2 during the first pandemic wave had died, 6 (11%) during the initial admission and 14 (25%) in the following months, mainly within the first 3 months after diagnosis. Overall, 30% of patients died from vascular causes and 40% from respiratory causes. In adjusted analysis, a positive SARS-CoV-2 PCR test for diagnosis {hazard ratio [HR] 5.18 [interquartile range (IQR) 1.30-20.65], P = 0.020}, higher baseline C-reactive protein levels [HR 1.10 (IQR 1.03-1.16), P = 0.002] and lower haemoglobin levels [HR 0.62 (IQR 0.45-0.86), P = 0.005] were associated with higher 1-year mortality. Mortality in the 144 patients who did not have COVID-19 was 21 (14.6%) over 12 months [HR of death for COVID-19 patients 3.00 (IQR 1.62-5.53), log-rank P = 0.00023]. Over the first year, the percentage of patients having anti-SARS-CoV-2 immunoglobulin G (IgG) decreased from 36/49 (73.4%) initially to 27/44 (61.3%) at 6 months and 14/36 (38.8%) at 12 months.

CONCLUSIONS

The high mortality of HD patients with COVID-19 is not limited to the initial hospitalization. Defining COVID-19 deaths as those occurring within 3 months of a COVID-19 diagnosis may better represent the burden of COVID-19. In HD patients, the anti-SARS-CoV-2 IgG response was suboptimal and short-lived.

Patients receiving hemodialysis do not lose SARS-CoV-2 antibodies more rapidly than non-renal controls: a prospective cohort study

Background

Method

Results

Conclusion

Decline of Humoral Responses 6 Months after Vaccination with BNT162b2 (Pfizer–BioNTech) in Patients on Hemodialysis

This study analyzed binding and neutralizing antibody titers up to 6 months after standard vaccination with BNT162b2 (two doses of 30 µg each) in SARS-CoV-2 naïve patients (n = 59) on hemodialysis. Humoral vaccine responses were measured before and 6, 12, and 24 weeks after the first vaccination. A chemiluminescent immunoassay (CLIA) was used to quantify SARS-CoV-2 IgG against the spike glycoprotein. SARS-CoV-2 neutralizing activity was tested against the wild-type virus. A multivariable binary regression model was used to identify risk factors for the absence of humoral immune responses at 6 months. At week 6, vaccine-specific seroconversion was detected in 96.6% of all patients with median anti-SARS-CoV-2 IgGs of 918 BAU/mL. At weeks 12 and 24, seroconversion rates decreased to 91.5% and 79.7%, and corresponding median binding antibody titers declined to 298 BAU/mL and 89 BAU/mL, respectively. Neutralizing antibodies showed a decay from 79.6% at week 6 to 32.8% at week 24. The risk factor with the strongest association for vanishing immune responses was low serum albumin (p = 0.018). Regarding vaccine-specific humoral responses 6 months after the standard BNT162b2 vaccination schedule, SARS-CoV-2 naïve patients receiving hemodialysis must be considered at risk of becoming infected with SARS-CoV-2 and being infectious.

Long-term impact of COVID-19 among maintenance haemodialysis patients

Background

Maintenance haemodialysis (MHD) patients have a high risk of initial mortality from coronavirus disease 2019 (COVID-19). However, long-term consequences of this disease in the MHD population are poorly described. We report the clinical presentation, outcome and long-term follow-up of MHD patients affected by COVID-19 in a multicentric cohort from the Paris, France area.

Methods

We conducted a retrospective analysis of clinical presentation and long-term follow-up of MHD patients affected by COVID-19 in 19 MHD centres in the Paris, France area.

Results

In this cohort of 248 patients with an initial mortality rate of 18%, age, comorbidities, dyspnoea and previous immunosuppressive treatment were associated with death at <30 days. Among the 203 surviving patients following the acute phase, long-term follow-up (median 180 days) was available for 189 (93%) patients. Major adverse events occurred in 30 (16%) patients during follow-up, including 12 deaths (6%) after a median of 78 days from onset of symptoms. Overall, cardiovascular events, infections and gastrointestinal bleeding were the main major adverse events. Post-COVID-19 cachexia was observed in 25/189 (13%) patients. Lower initial albuminaemia was significantly associated with this cachexia. No reinfection with severe acute respiratory syndrome coronavirus 2 was observed.

Conclusions

This work demonstrates the long-term consequences of COVID-19 in MHD patients, highlighting both initial and long-term severity of the disease, including severe cachexia.

Analytical and Clinical Evaluation of the Semiquantitative Elecsys Anti-SARS-CoV-2 Spike Protein Receptor Binding Domain Antibody Assay on the Roche cobas e602 Analyzer

Objectives

To analytically and clinically evaluate the semiquantitative Elecsys anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein antibody (S-Ab) assay on the Roche cobas e602 analyzer.

Methods

The S-Ab assay is a 1-step, double-antigen sandwich electrochemiluminescent immunoassay that semiquantitatively measures total IgG, IgM, and IgA antibodies specific for the receptor binding domain of SARS-CoV-2 spike protein in serum or plasma. The S-Ab assay was evaluated for precision, linearity, interference (by hemoglobin, bilirubin, triglycerides, and biotin), cross-reactivity, and clinical performance, and was compared to the qualitative Elecsys anti-nucleocapsid (N-Ab) immunoassay, a lateral flow device that qualitatively detects S-Ab and N-Ab, and an anti-spike enzyme-linked immunosorbent assay (ELISA).

Results

S-Ab assay is precise, exhibits linearity from 0.4 to 250 U/mL, is unaffected by significant cross-reactivity or interferences, and qualitatively demonstrates greater than 90% concordance with N-Ab assay and lateral flow device. Readouts of S-Ab assay correlate with ELISA, which in turn correlates strongly with SARS-CoV-2 virus neutralization assay, and exhibit 100% sensitivity and specificity for COVID-19 patient samples obtained at or more than 14 days after PCR positivity.

Conclusions

The S-Ab assay is a robust clinical test for qualitative and semiquantitative detection of seropositivity following SARS-CoV-2 infection or spike-encoding mRNA COVID-19 vaccination.

Seroprevalence and levels of IgG antibodies after COVID-19 infection or vaccination

BACKGROUND

In a country-wide seroprevalence study of COVID-19 in Estonia, we aimed to determine the seroprevalence and the dynamics of IgG against SARS-CoV-2 after vaccination or positive PCR-test.

METHODS

Leftover blood samples were selected between 8 February and 25 March 2021, by SYNLAB Estonia from all counties and age groups (0-9, 10-19, 20-59, 60-69, 70-79 and 80-100 years) proportionally to the whole Estonian population and tested for IgG against SARS-CoV-2 spike protein receptor-binding domain (anti-S-RBD IgG) using Abbott SARS-CoV-2 IgG II Quant assay. Antibody levels after positive PCR-test or vaccination were described by exponential increase-decrease models.

RESULTS

According to total of 2517 samples, overall seroprevalence (95% confidence interval [CI]) was 20.1% (18.5-21.7%), similar in all age groups, but varied between counties. If individuals vaccinated with the first dose at least 14 d before antibody measurement were assumed to be seronegative, the overall seroprevalence was 15.8% (14.4-17.3%), 4.0-fold larger than the proportion of PCR-confirmed COVID-19 cases. Of seropositive individuals (n = 506) 194 (38.3%; 33.8-43.1%) had not had positive PCR-test or been vaccinated. According to exponential increase-decrease model, the peak of anti-S-RBD IgG in a 52-year-old (median age of PCR-positive and/or vaccinated individuals) was significantly higher after vaccination compared with positive PCR-test (22,082 (12,897-26,875) vs. 6732 (2321-8243) AU/mL), but half-life was similar (26.5 (6.9-46.1) vs. 38.3 (8.2-68.5) d).

CONCLUSIONS

One year after the start of COVID-19 pandemic the actual prevalence of infection is still underestimated compared with PCR-confirmed COVID-19 cases. Older compared with younger individuals have lower anti-S-RBD IgG level after vaccination, but similar decline rate.

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.

SARS-CoV-2 Antibodies in Hemodialysis Patients Six Months after Infection Compared to Healthcare Workers

Background

The humoral response to SARS-CoV-2 infection in hemodialysis patients needs to be clarified.

Methods

In this retrospective study performed in two dialysis facilities, we measured the circulating levels of SARS-CoV-2 antibodies in patients who were on maintenance hemodialysis during the first wave of the epidemic in March and April 2020 and were still alive 6 months later. We also investigated associations between the patients diagnosed as infected during the first wave and several clinical, biological, and radiological parameters of COVID-19. Finally, we compared these circulating levels of SARS-CoV-2 antibodies with those of a control group of healthcare workers infected during the same period.

Results

Of the 299 hemodialysis patients who recovered from the first wave of the epidemic 6 months before, 59 had a positive SARS-CoV-2 antibody whereas only 45 patients were diagnosed as infected during the first wave of the epidemic. All infected hemodialysis patients developed circulating antibodies. Using a clustering method, a significant correlation was identified between the cluster with the lowest circulating levels of SARS-CoV-2 antibodies and the severity of COVID-19 based on several parameters including CRP, BNP, lymphocyte count, neutrophil-lymphocyte ratio, and oxygen requirements, as well as pulmonary involvement on chest scan. Moreover, the circulating levels of the SARS-CoV-2 antibodies in surviving hemodialysis patients (n = 59) were similar to those of the control group (n = 17).

Conclusion

The main finding of this study is that all of the surviving hemodialysis patients who were diagnosed with SARS-CoV-2 infection from March to April 2020 developed a persistent humoral response with significant circulating levels of SARS-CoV-2 antibodies, 6 months later. Another important finding is that surviving hemodialysis patients who had more severe disease had lower circulating levels of SARS-CoV-2 antibodies. Finally, circulating levels of SARS-CoV-2 antibodies were similar in surviving hemodialysis patients and healthcare workers without kidney disease.

Humoral response to SARS-CoV-2 is well preserved and symptom dependent in kidney transplant recipients

Data on the immune response to SARS-CoV-2 in kidney transplant recipients are scarce. Thus, we conducted a single-center observational study to assess the anti-SARS-CoV-2 IgG seroprevalence in outpatient kidney transplant recipients (KTR; n = 1037) and healthcare workers (HCW; n = 512) during the second wave of the COVID-19 pandemic in fall 2020 and evaluated the clinical variables affecting antibody levels. Antibodies against S1 and S2 subunit of SARS-CoV-2 were evaluated using immunochemiluminescent assay (cut off 9.5 AU/ml, sensitivity of 91.2% and specificity of 90.2%). Anti-SARS-CoV-2 IgG seroprevalence was lower in KTR than in HCW (7% vs. 11.9%, p = .001). Kidney transplant recipients with SARS-CoV-2 infection were younger (p = .001) and received CNI-based immunosuppression more frequently (p = .029) than seronegative KTR. Anti-SARS-CoV-2 IgG positive symptomatic KTR had a higher BMI (p = .04) than asymptomatic KTR. Interestingly, anti-SARS-CoV-2 IgG levels were higher in KTR than in HCW (median 31 AU/ml, IQR 17-84 vs. median 15 AU/ml, IQR 11-39, p < .001). The presence of moderate to severe symptoms in KTR was found to be the only independent factor affecting IgG levels (Beta coefficient = 41.99, 95% CI 9.92-74.06, p = .011) in the multivariable model. In conclusion, KTR exhibit a well-preserved symptom-dependent humoral response to SARS-CoV-2 infection.

Humoral response to BNT162b2 mRNA COVID-19 vaccine in peritoneal and hemodialysis patients: A comparative study

Introduction

Maintenance dialysis patients (MDP) are at higher risk of exposure with increased mortality from COVID‐19 with generalized immunization becoming the cornerstone in prevention. This study aims to compare humoral response between hemodialysis (HD) and peritoneal dialysis (PD) patients.

Materials and Methods

Observational prospective study following HD and PD programs from a Portuguese Center receiving BNT162b2 vaccine. Specific anti‐Spike IgG quantification to compare both for absolute value and non‐responders (NR) between modalities and against risk factors.

Results

Of 67 MDP, 42 were HD and 25 PD patients. PD developed higher antibody titers after both first (median 5.44 vs. 0.99 AU/ml, p < 0.01) and second dose (median 170.43 vs. 65.81 AU/ml; p < 0.01). HD associated with NR after the first dose (p < 0.01).

Conclusion

This study demonstrated improved humoral immunogenicity with BNT162b2 in PD compared to HD patients. These differences are attributed to comorbidity burden and age differences, rather than dialysis modality.

SARS-CoV-2-specific Humoral and Cellular Immunities in Kidney Transplant Recipients and Dialyzed Patients Recovered From Severe and Nonsevere COVID-19

Kidney transplantation and dialysis are two major risk factors for severe forms of coronavirus disease 2019 (COVID-19). The dynamics of the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in this population remain largely unknown.

Methods

We report here the analysis of anti-SARS-CoV-2 antibody- and T cell-mediated immune responses in 26 kidney transplant recipients (KTRs) and 11 dialyzed patients (DPs) who recovered from COVID-19.

Results

After a mean time of 83 ± 26 d post-symptom onset for KTRs and 97 ± 31 d for DPs, 20 KTRs (76.9%) and 10 DPs (90.9%) displayed anti-S1 immunoglobulin G SARS-CoV-2 antibodies (P = 0.34), at similar titers in both groups. SARS-CoV-2-specific interferon-γ-producing T cells were evidenced in 26 KTRs (100%) and 10 DPs (90.9%). Total numbers of SARS-CoV-2-reactive T cells were high and not statistically different between the 2 groups. No correlation between the severity of the disease and the number of reactive T cells was found in KTRs. In 5 KTRs, also evaluated 10 mo after COVID-19, weak or absent antibody response was observed, whereas specific memory T-cell response was detected in all cases.

Conclusion

T-cell response persisted up to 3 mo post-symptom onset, even in KTRs in whom full immunosuppressive regimen was reinstated at recovery, and seems to be present up to 10 mo after infection. Our findings have implications in the understanding of the natural course of the disease in transplant patients and DPs.

Prevalence of SARS-CoV-2 antibodies in hemodialysis patients in Senegal: a multicenter cross-sectional study

BACKGROUND

Hemodialysis patients are among high-risk groups for COVID-19. Africa is the continent with the lowest number of cases in the general population but we have little information about the disease burden in dialysis patients.

OBJECTIVES

This study aimed to describe the seroprevalence of SARS-CoV-2 antibodies in the hemodialysis population of Senegal.

PATIENTS AND METHODS

We conducted a multicenter cross-sectional survey, between June and September 2020 involving 10 public dialysis units randomly selected in eight regions of Senegal. After seeking their consent, we included 303 patients aged ≥ 18 years and hemodialysis for ≥ 3 months. Clinical symptoms and biological parameters were collected from medical records. Patients' blood samples were tested with Abbott SARS-CoV-2 Ig G assay using an Architect system. Statistical tests were performed with STATA 12.0.

RESULTS

Seroprevalence of SARS-CoV-2 antibodies was 21.1% (95% CI = 16.7-26.1%). We noticed a wide variability in SARS-CoV-2 seroprevalence between regions ranging from 5.6 to 51.7%. Among the 38 patients who underwent nasal swab testing, only six had a PCR-confirmed infection and all of them did seroconvert. Suggestive clinical symptoms were reported by 28.1% of seropositive patients and the majority of them presented asymptomatic disease. After multivariate analysis, a previous contact with a confirmed case and living in a high population density region were associated with the presence of SARS-CoV-2 antibodies.

CONCLUSION

This study presents to our knowledge the first seroprevalence data in African hemodialysis patients. Compared to data from other continents, we found a higher proportion of patients with SARS-CoV-2 antibodies but a lower lethality rate.

Humoral response to a third injection of BNT162b2 vaccine in patients on maintenance haemodialysis

BACKGROUND

Humoral response against sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after two doses of BNT162b2 (Pfizer-BioNTech) has been proven to be less intense in maintenance dialysis patients as compared with healthy subjects, leading the French authorities to recommend a third injection in this population. Here we investigated the response to the third injection in two cohorts of haemodialysis (HD) patients.

METHODS

Data from two prospective observational cohorts were collected. In the first ('systematic') cohort, patients from two HD centres (n = 66) received a third injection of BNT162b2, regardless of the response after two injections. In the second ('conditional') cohort, the injection was only prescribed to patients (n = 34) with no or low response to the previous two doses. In both cohorts, the third dose was injected 1-2 months after the second dose. Serology was performed after the second and third doses to assess anti-Spike immunoglobulin G (S IgG) antibody titre.

RESULTS

In the systematic cohort, anti-S IgG was found in 83.3 and 92.4% of patients after the second and third doses of BNT162b2, respectively. In this cohort, 6/11 (54.5%) and 20/21 (95.2%) patients switched from non-responder to low responder and from low responder to high responder, respectively. In low and high responders to two doses, 50/55 (90.9%) at least doubled their anti-S IgG titre. Similar trends were observed in the conditional cohort.

CONCLUSIONS

In maintenance HD patients, humoral response against SARS-CoV-2 was boosted after a third dose of BNT162b2, allowing seroconversion in more than half of non-responders. These data may support an intensified vaccination protocol with a third dose of BNT162b2 in dialysis patients.

Automated ELISA On-Chip for the Detection of Anti-SARS-CoV-2 Antibodies

The COVID-19 pandemic has been the most critical public health issue in modern history due to its highly infectious and deathly potential, and the limited access to massive, low-cost, and reliable testing has significantly worsened the crisis. The recovery and the vaccination of millions of people against COVID-19 have made serological tests highly relevant to identify the presence and levels of SARS-CoV-2 antibodies. Due to its advantages, microfluidic-based technologies represent an attractive alternative to the conventional testing methodologies used for these purposes. In this work, we described the development of an automated ELISA on-chip capable of detecting anti-SARS-CoV-2 antibodies in serum samples from COVID-19 patients and vaccinated individuals. The colorimetric reactions were analyzed with a microplate reader. No statistically significant differences were observed when comparing the results of our automated ELISA on-chip against the ones obtained from a traditional ELISA on a microplate. Moreover, we demonstrated that it is possible to carry out the analysis of the colorimetric reaction by performing basic image analysis of photos taken with a smartphone, which constitutes a useful alternative when lacking specialized equipment or a laboratory setting. Our automated ELISA on-chip has the potential to be used in a clinical setting and mitigates some of the burden caused by testing deficiencies.

Kinetics of anti-SARS-CoV-2 IgG antibody levels and potential influential factors in subjects with COVID-19: A 11-month follow-up study

We aim to study kinetics of anti-SARS-CoV-2 IgG antibody levels in subjects with COVID-19 for up to 11 months and the potential influential factors. The study was a prospective longitudinal study. The analyses were based on 77 serum/plasma samples with a mean of 4 samples per participant (range 1 – 18) in 20 participants with at least one positive Polymerase Chain Reaction testing result from 19 March 2020 up to 10 February 2021. Among the subjects (median age 34.5 years, 65% male), IgG level declined with the follow-up time (per month; geometric mean ratio [GMR] 0.73; 95% CI, 0.72 – 0.74). In a small sample of subjects from the general population with COVID-19, IgG levels declined non-linearly from month 2 to 11 with individual heterogeneity in quantity and changing speed and may be associated with gender, race and the loss of smell and taste.

Humoral response after SARS-CoV-2 mRNA vaccines in dialysis patients: Integrating anti-SARS-CoV-2 Spike-Protein-RBD antibody monitoring to manage dialysis centers in pandemic times

Dialysis patients are both the most likely to benefit from vaccine protection against SARS-CoV-2 and at the highest risk of not developing an immune response. Data from the medical field are thus mandatory. We report our experience with a BNT162b2-mRNA vaccine in a retrospective analysis of 241 dialysis patients including 193 who underwent anti-Spike-Protein-Receptor-Binding-Domain (RBD) IgG analysis. We show that a pro-active vaccine campaign is effective in convincing most patients to be vaccinated (95%) and frequently elicits a specific antibody response (94.3% after two doses and 98.4% after three doses). Only immunocompromised Status is associated with lack of seroconversion (OR 7.6 [1.5–38.2], p = 0.02). We also identify factors associated with low response (last quartile; IgG<500AU/mL): immunocompromised status, age, absence of RAAS inhibitors, low lymphocytes count, high C Reactive Protein; and with high response (high quartile; IgG>7000AU/mL): age; previous SARS-CoV-2 infection and active Cancer. From this experience, we propose a strategy integrating anti-spike IgG monitoring to guide revaccination and dialysis center management in pandemic times.

Antibody response to mRNA SARS-CoV-2 vaccines in haemodialysis patients

Background

Some studies have shown an attenuated immune response in haemodialysis patients after vaccination. The present study examines the humoral response after mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a large population of haemodialysis patients from different outpatient dialysis centres.

Methods

We retrospectively assessed antibodies against SARS-CoV-2 spike protein and nucleocapsid protein (chemiluminescence immunoassays, Roche diagnostics) 3–6 weeks after the second mRNA vaccine dose in 179 maintenance haemodialysis and 70 non-dialysis patients (control cohort). Differences in anti-SARS-CoV-2 spike protein titers were statistically analysed with respect to patient-relevant factors, including age, gender, previous coronavirus disease 2019 (COVID-19) infection, systemic immunosuppressive therapy and time on dialysis.

Results

We found a favourable, but profoundly lower SARS-CoV-2 spike protein antibody response in comparison with a non-dialysis cohort (median 253.5 versus 1756 U/mL, P < 0.001). In multivariate analysis, previous COVID-19 infection (P < 0.001) and female gender were associated with a significantly higher vaccine response (P = 0.006) in haemodialysis patients, while there was a significant inverse correlation with increasing patient age and systemic immunosuppression (P < 0.001). There was no statistically significant correlation between the antibody titer and time on dialysis. Immune response in haemodialysis patients with a previous COVID-19 infection led to substantially higher antibody titers that were equal to those of vaccinated non-dialysis individuals with previous infection.

Conclusion

We strongly argue in favour of regular antibody testing after COVID-19 vaccination in haemodialysis patients. Further studies should elucidate the utility of booster vaccinations to foster a stronger and persistent antibody response.

Clinical Course of SARS-CoV-2 Infection in Adults with ESKD Receiving Outpatient Hemodialysis

Background

Patients with ESKD on maintenance dialysis receive dialysis in common spaces with other patients and have a higher risk of severe SARS-CoV-2 infections. They may have persistently or intermittently positive SARS-CoV-2 RT-PCR tests after infection. We describe the clinical course of SARS-CoV-2 infection and the serologic response in a convenience sample of patients with ESKD to understand the duration of infectivity.

Methods

From August to November 2020, we enrolled patients on maintenance dialysis with SARS-CoV-2 infections from outpatient dialysis facilities in Atlanta, Georgia. We followed participants for approximately 42 days. We assessed COVID-19 symptoms and collected specimens. Oropharyngeal (OP), anterior nasal (AN), and saliva (SA) specimens were tested for the presence of SARS-CoV-2 RNA, using RT-PCR, and sent for viral culture. Serology, including neutralizing antibodies, was measured in blood specimens.

Results

Fifteen participants, with a median age of 58 (range, 37‒77) years, were enrolled. Median duration of RT-PCR positivity from diagnosis was 18 days (interquartile range [IQR], 8‒24 days). Ten participants had at least one, for a total of 41, positive RT-PCR specimens ≥10 days after symptoms onset. Of these 41 specimens, 21 underwent viral culture; one (5%) was positive 14 days after symptom onset. Thirteen participants developed SARS-CoV-2-specific antibodies, 11 of which included neutralizing antibodies. RT-PCRs remained positive after seroconversion in eight participants and after detection of neutralizing antibodies in four participants; however, all of these samples were culture negative.

Conclusions

Patients with ESKD on maintenance dialysis remained persistently and intermittently SARS-CoV-2-RT-PCR positive. However, of the 15 participants, only one had infectious virus, on day 14 after symptom onset. Most participants mounted an antibody response, including neutralizing antibodies. Participants continued having RT-PCR-positive results in the presence of SARS-CoV-2-specific antibodies, but without replication-competent virus detected.

SARS-CoV-2 Antibody Response After a Third Dose of the BNT162b2 Vaccine in Patients Receiving Maintenance Hemodialysis or Peritoneal Dialysis

Rationale & Objective

Recent studies showed that antibody titers after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the dialysis population are diminished as compared with the general population, suggesting the possible value of a third booster dose. We characterized the humoral response after 3 doses of the BNT162b2 vaccine in patients treated with either maintenance hemodialysis (HD) or peritoneal dialysis (PD).

Study Design

Case series.

Setting & Participants

69 French patients (38 HD and 31 PD) treated at a single center who received 3 doses of the BNT162b2 vaccine.

Findings

Humoral response was evaluated using plasma levels of anti-SARS-CoV-2 spike protein S1 immunoglobulin measured after the second dose and at least 3 weeks after the third dose of the BNT162b2 vaccine. Patients (median age 68 years [interquartile range (IQR), 53-76 years], 65% men) had a median anti-S1 antibody level of 284 [IQR, 83-1190] AU/mL after the second dose, and 7,554 [IQR, 2,268-11,736] AU/mL after the third dose. Three patients were nonresponders (anti-S1 antibody level < 0.8 AU/mL), and 12 were weak responders (anti-S1 antibody level 0.8-50 AU/mL) after the second vaccine dose. After the third dose, 1 of the 3 initial nonresponders produced anti-spike antibody, and all the 12 initial weak responders increased their antibody levels. Patients with a greater increase in anti-S1 antibody levels after a third dose had lower antibody levels after the second dose, and a longer time interval between the second and the third dose. Adverse events did not seem to be more common or severe after a third vaccine dose.

Limitations

Observational study, small sample size. Relationship between antibody levels and clinical outcomes is not well understood.

Conclusions

A third dose of the BNT162b2 vaccine substantially increased antibody levels in patients receiving maintenance dialysis and appeared to be as well tolerated as a second dose.

Humoral Responses to Single-Dose BNT162b2 mRNA Vaccination in Dialysis Patients Previously Infected With SARS-CoV-2

Seroconversion rates following infection and vaccination are lower in dialysis patients compared to healthy controls. There is an urgent need for the characterization of humoral responses and success of a single-dose SARS-CoV-2 vaccination in previously infected dialysis patients. We performed a dual-center cohort study comparing three different groups: 25 unvaccinated hemodialysis patients after PCR-confirmed COVID-19 (Group 1), 43 hemodialysis patients after two-time BNT162b2 vaccination without prior SARS-CoV-2 infection (Group 2), and 13 single-dose vaccinated hemodialysis patients with prior SARS-CoV-2 infection (Group 3). Group 3 consists of seven patients from Group 1 and 6 additional patients with sera only available after single-dose vaccination. Anti-S1 IgG, neutralizing antibodies, and antibodies against various SARS-CoV-2 protein epitopes were measured 3 weeks after the first and 3 weeks after the second vaccination in patients without prior SARS-CoV-2 infection, 6 weeks after the onset of COVID-19 in unvaccinated patients, and 3 weeks after single-dose vaccination in patients with prior SARS-CoV-2 infection, respectively. Unvaccinated patients after COVID-19 showed a significantly higher neutralizing antibody capacity than two-time vaccinated patients without prior COVID-19 [median (IQR) percent inhibition 88.0 (71.5-95.5) vs. 50.7 (26.4-81.0); P = 0.018]. After one single vaccine dose, previously infected individuals generated 15- to 34-fold higher levels of anti-S1 IgG than age- and dialysis vintage-matched unvaccinated patients after infection or two-time vaccinated patients without prior SARS-CoV-2 infection with a median (IQR) index of 274 (151-791) compared to 18 (8-41) and 8 (1-21) (for both P < 0.001). With a median (IQR) percent inhibition of 97.6 (97.2-98.9), the neutralizing capacity of SARS-CoV-2 antibodies was significantly higher in single-dose vaccinated patients with prior SARS-CoV-2 infection compared to other groups (for both P < 0.01). Bead-based analysis showed high antibody reactivity against various SARS-CoV-2 spike protein epitopes after single-dose vaccination in previously infected patients. In conclusion, single-dose vaccination in previously infected dialysis patients induced a strong and broad antibody reactivity against various SARS-CoV-2 spike protein epitopes with high neutralizing capacity.

Twelve-month specific IgG response to SARS-CoV-2 receptor-binding domain among COVID-19 convalescent plasma donors in Wuhan

To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.

[COVID-19 vaccination in dialysis and kidney transplant patients]

Au cours de la COVID-19, la dialyse et la transplantation rénale ont été identifiées comme d’importants facteurs de risque de développer une forme sévère de la maladie. La réponse immunitaire humorale post-infection est durable. Cependant, après vaccination, celle-ci apparaît plus limitée, tant en termes de taux de réponse (séropositivité post-vaccination) qu’en termes de taux quantitatif d’anticorps. Alors que les patients dialysés ont un taux de réponse de 80–95 % en fonction des études, la réponse est particulièrement faible chez les patients transplantés rénaux, avec des taux de séropositivité de 30–50 %, et notamment s’ils sont traités par bélatacept (environ 5 % de réponse). Ces éléments ont poussé à proposer des schémas vaccinaux alternatifs en France, avec notamment l’utilisation d’une 3^e injection de vaccin ARNm. Malgré ces résultats, de nombreuses questions sur la vaccination des insuffisants rénaux restent en suspens, concernant notamment la qualité des réponses cellulaires (encore peu étudiées), la durabilité des réponses post-vaccinales, et surtout l’efficacité clinique des vaccins.

Persistence of humoral response upon SARS-CoV-2 infection

SARS‐CoV‐2 continues to leave its toll on global health and the economy. Management of the pandemic will rely heavily on the degree of adaptive immunity persistence following natural SARS‐CoV‐2 infection. Along with the progression of the pandemic, more literature on the persistence of the SARS‐CoV‐2‐specific antibody response is becoming available. Here, we summarize findings on the persistence of the humoral, including neutralizing antibody, response at three to eight months post SARS‐CoV‐2 infection in non‐pregnant adults. While the comparability of the literature is limited, findings on the detectability of immunoglobulin G class of antibodies (IgG) were most consistent and were reported in most studies to last for six to eight months. Studies investigating the response of immunoglobins M and A (IgM, IgA) were limited and reported mixed results, in particular, for IgM. The majority of studies observed neutralizing antibodies at all time points tested, which in some studies lasted up to eight months. The presence of neutralizing antibodies has been linked to protection from re‐infection, suggesting long‐term immunity to SARS‐CoV‐2. These neutralizing capacities may be challenged by emerging virus variants, but mucosal antibodies as well as memory B and T cells may optimize future immune responses. Thus, further longitudinal investigation of PCR‐confirmed seropositive individuals using sensitive assays is warranted to elucidate the nature and duration of a more long‐term humoral response.

Passive Immunity Should and Will Work for COVID-19 for Some Patients

In the absence of effective antiviral chemotherapy and still in the context of emerging vaccines for severe acute respiratory syndrome-CoV-2 infections, passive immunotherapy remains a key treatment and possible prevention strategy. What might initially be conceived as a simplified donor-recipient process, the intricacies of donor plasma, IV immunoglobulins, and monoclonal antibody modality applications are becoming more apparent. Key targets of such treatment have largely focused on virus neutralization and the specific viral components of the attachment Spike protein and its constituents (e.g., receptor binding domain, N-terminal domain). The cumulative laboratory and clinical experience suggests that beneficial protective and treatment outcomes are possible. Both a dose- and a time-dependency emerge. Lesser understood are the concepts of bioavailability and distribution. Apart from direct antigen binding from protective immunoglobulins, antibody effector functions have potential roles in outcome. In attempting to mimic the natural but variable response to infection or vaccination, a strong functional polyclonal approach attracts the potential benefits of attacking antigen diversity, high antibody avidity, antibody persistence, and protection against escape viral mutation. The availability and ease of administration for any passive immunotherapy product must be considered in the current climate of need. There is never a perfect product, but yet there is considerable room for improving patient outcomes. Given the variability of human genetics, immunity, and disease, and given the nuances of the virus and its potential for change, passive immunotherapy can be developed that will be effective for some but not all patients. An understanding of such patient variability and limitations is just as important as the understanding of the direct interactions between immunotherapy and virus.

Acute Kidney Injury and Advanced Kidney Disease in the COVID-19 Pandemic: Proceedings From a National Kidney Foundation Symposium

The coronavirus disease 2019 (COVID-19) pandemic is an unprecedented and historic public health crisis that continues to expand and evolve. The National Kidney Foundation held a 2-part continuing medical education live virtual symposium on July 16 and July 24, 2020, to address the multiple challenges of COVID-19 in the context of advanced chronic kidney disease. Faculty addressed the pathophysiology, impact, risks, and management of COVID-19 as it relates to advanced kidney disease. Testing, risk mitigation, and inpatient and outpatient management were also addressed. This concise review addresses major findings of the symposium along with certain updates regarding vaccinations since then. These findings include: (1) severe COVID-19 infection has been associated with acute kidney injury, (2) it is essential to prevent and actively manage acute kidney injury to decrease mortality in these critically ill patients, (3) management of patients with advanced kidney disease should be geared toward minimizing their risk for exposure while making sure they are receiving adequate treatments, and (4) patients with kidney disease, especially ones in advanced stages, should be prioritized for vaccination.