SARS-CoV-2 Vaccination in Kidney Transplant Recipients—Stratified Analysis of the Humoral Immune Response

Background. Kidney transplant recipients are at increased risk of SARS-CoV-2 infection and a more severe course of COVID-19. Methods. We conducted a quantitative serologic testing of antibodies specific for the wild type of SARS-CoV-2 and the Omicron variant of concern before and after a third-dose vaccination, either mRNA-1273 (Moderna) or BNT162b2 (Pfizer-BioNTech) in a cohort of 103 stable kidney transplant recipients (median [range] age, 58 [22–84] y, 57 men [55.3%]). Results. Third-dose vaccination increased the seroconversion rate from 57.3% to 71.8%. However, despite a marked rise of the antibody concentrations after the booster, 55.4% and 11.6% only formed neutralizing antibodies against the SARS-CoV-2 wild type and Omicron, respectively. Treatment with mycophenolic acid/mycophenolate mofetil (in strata of the dose quartiles), advanced age, and‚ above all‚ impaired renal function (eGFR <60 mL/min) adversely influenced the humoral immunity regarding seroconversion and inhibition of the wild type of SARS-CoV-2. Conclusions. Apart from immunosuppressive therapy, the humoral vaccination response is largely affected by nonmodifiable factors in kidney transplant recipients. With the currently leading and clinically easier Omicron variant, this puts into perspective the strategy to significantly enhance the protective efficacy of the available vaccines by reducing or temporarily stopping proliferation inhibitors, not least considering the inherent rejection risk with a possible deterioration of graft function.

Heterologous immunization with BNT162b2 followed by mRNA-1273 in dialysis patients: seroconversion and presence of neutralizing antibodies.

INTRODUCTION: The vital renal replacement therapy makes it impossible for dialysis patients to distance themselves socially. This results in a high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and developing coronavuris disease 2019, with excess mortality due to disease burden and immunosuppression. We determined the efficacy of a 100-µg booster of mRNA-1273 (Moderna, Cambridge, MA, USA) 6 months after two doses of BNT162b2 (BioNTech/Pfizer, Mainz, Germany/New York, USA) in 194 SARS-CoV-2-naïve dialysis patients. METHODS: Anti-SARS-CoV-2 spike antibodies were measured with the Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics, Mannheim, Germany) 4 and 10-12 weeks after two doses of BNT162b2 as well as 4 weeks after the mRNA-1273 booster. The presence of neutralizing antibodies was measured by the SARS-CoV-2 Surrogate Virus Neutralization Test (GenScript Biotech, Piscataway, NJ, USA). Two different cut-offs for positivity were used, one according to the manufacturer's specifications and one correlating with positivity in a plaque reduction neutralization test (PRNT). Receiver operating characteristics analyses were performed to match the anti-SARS-CoV-2 spike antibody cut-offs with the cut-offs in the surrogate neutralization assay accordingly. RESULTS: Any level of immunoreactivity determined by the anti-SARS-CoV-2 spike antibody assay was found in 87.3% (n = 144/165) and 90.6% (n = 164/181) of patients 4 and 10-12 weeks, respectively, after two doses of BNT162b2. This was reduced to 68.5% or 60.6% 4 weeks and 51.7% or 35.4% 10-12 weeks, respectively, when using the ROC cut-offs for neutralizing antibodies in the surrogate neutralization test (manufacturer's cut-off ≥103 U/mL and cut-off correlating with PRNT ≥196 U/mL). Four weeks after the mRNA-1273 booster, the concentration of anti-SARS-CoV-2 spike antibodies increased to 23 119.9 U/mL and to 97.3% for both cut-offs of neutralizing antibodies. CONCLUSION: Two doses of BNT162b2 followed by one dose of mRNA-1273 within 6 months in patients receiving maintenance dialysis resulted in significant titres of SARS-CoV-2 spike antibodies. While two doses of mRNA vaccine achieved adequate humoral immunity in a minority, the third vaccination boosts the development of virus-neutralizing quantities of SARS-CoV-2 spike antibodies (against wild-type SARS-CoV-2) in almost all patients.

Prevalence of subjective impairments of the sense of smell and taste in employees of retirement and nursing homes during SARS-CoV-2 pandemic.

AIM: To investigate the usability of querying subjective impairments of the sense of smell and taste in order to improve pre-test probability in testing for SARS-CoV-2. To achieve this, exploring the prevalence of these restrictions in the COVID-19-negative population, as well as nasal co-symptoms. DESIGN: A cross-sectional study was carried out as part of the secondary prophylaxis, following the STROBE guidelines of the EQUATOR network. METHODS: In total, 1,734 employees of retirement and nursing homes were tested for COVID-19 and asked for subjective reduction or loss in the sense of smell and taste, furthermore about nasal co-symptoms such as nasal obstruction and rhinorrhoea. RESULTS: All employees tested negative for COVID-19. Subjective hyposmia and hypogeusia rarely occurred and were usually accompanied by other nasal symptoms such as nasal obstruction. Querying subjective hyposmia/anosmia or hypogeusia/ageusia appears to be a useful anamnestic instrument for the clinical assessment of the probability of SARS-CoV-2 infection.