Clinical effectiveness of coronavirus disease 2019 vaccination in patients with multiple sclerosis stratified by disease-modifying treatment.

BACKGROUND AND PURPOSE: Coronavirus disease 2019 (COVID-19) vaccination has been associated with a dampened humoral and/or cellular immune response in patients with multiple sclerosis (MS) who were concurrently on disease-modifying treatment (DMT) with B-cell depleting agents or sphingosine-1-phosphate receptor modulators (S1PRMs). Our main goal was to investigate the impact of these DMT classes on the clinical effectiveness of COVID-19 vaccination. METHODS: Since March 2020, demographics and clinical data of patients with MS who developed COVID-19 have been collected at the Belgian National MS Centre in Melsbroek. Patients were considered to be 'protected by vaccination' if they were (i) fully vaccinated and (ii) tested positive for COVID-19 in the period ranging from 14 days to 6 months after the last administered vaccine. RESULTS: On 19 December 2022, 418 COVID-19 cases were retrospectively identified in 389 individual patients. Hospitalization and mortality rates resulting from the infection were 10.8% and 2.4%, respectively. Being 'unprotected by vaccination' was significantly associated with a worse COVID-19 outcome (i.e., hospitalization and/or death) in the total cohort (N = 418, odds ratio [OR] 3.96), in patients on ongoing DMT other than anti-CD20 agents or S1PRMs (N = 123, OR 31.75) and in patients without DMT (N = 182, OR 5.60), but not in those receiving anti-CD20 agents (N = 91, OR 0.39); the S1PRMs subgroup was considered too small (22 infections) for any meaningful analysis. CONCLUSIONS: Coronavirus disease 2019 vaccination protects against severe infection in patients with MS but it was not possible to confirm this effect in those on DMT with B-cell depleting agents.

Risk for excessive anticoagulation during hemodialysis is associated with type of vascular access and bedside coagulation testing: Results of a cross-sectional study.

Background: Recommendations and practice patterns for heparin dosing during hemodialysis show substantial heterogeneity and are scantly supported by evidence. This study assessed the variability in unfractionated heparin (UFH) dosing during hemodialysis and its clinical and biological anticoagulatory effects, and identified explanatory factors of heparin dosing. Methods: Cross-sectional study assessing UFH dosing, coagulation tests - activated partial thromboplastin time (aPTT) and activated clotting time (ACT) before dialysis start, 1 h after start and at treatment end (4 h) - and measurement of residual blood compartment volume of used dialyzers. Results: 101 patients, 58% male, with a median dialysis vintage of 33 (6-71) months received hemodialysis using a total UFH dose of 9,306 ± 4,079 (range 3,000-23,050) IU/session. Use of a dialysis catheter (n = 56, 55%) was associated with a 1.4 times higher UFH dose (p < 0.001) irrespective of prior access function. aPTT increased significantly more than ACT both 1 h and 4 h after dialysis start, independent of the dialysis access used. 53% of patients with catheter access and ACT ratio < 1.5, 1 h after dialysis start had simultaneous aPTT ratios > 2.5. Similar findings were present at 1 h for patients with AVF/AVG and at dialysis end for catheter use. No clinically significant clotting of the extracorporeal circuit was noted during the studied sessions. Dialyzer's blood compartment volume was reduced with a median of 9% (6-20%) without significant effect of UFH dose, aPTT or ACT measurements and vascular access type. Conclusion: UFH dose adaptations based on ACT measurements frequently result in excessive anticoagulation according to aPTT results. Higher doses of UFH are used in patients with hemodialysis catheters without evidence that this reduces dialyzer clotting.