Improved immunologic response to COVID19 vaccine with continuous dosing interval in haemodialysis patients

Improved immunologic response to COVID19 vaccine with continuous dosing interval in haemodialysis patients. time between vaccine doses did not differ Sulindac (Clinoril) between groups (P= .7). Increasing SARSCoV2 antibody titres were independently associated with increasing time between vaccine doses (B 0.241,P= .02), decreasing serum calcium levels (B 0.233,P= .007) and previous COVID19 (B 1.078,P< .001). In conclusion, a longer interval between COVID19 mRNA vaccine doses, lower calcium and a previous COVID19 contamination were independently associated with a stronger immunologic vaccination response in haemodialysis patients. While the response rate Sulindac (Clinoril) was good, only a minority developed high antibody titres, 47 (4350) days after the second vaccine dose. Keywords:antiSARSCoV2 spike protein IgG antibodies, Coronavirus, COVID19, haemodialysis, SARSCoV2, vaccination == 1. INTRODUCTION == Patients with chronic kidney disease (CKD) are especially vulnerable to contamination with 2019 coronavirus disease (COVID19) and develop more often serious complications than other populations.1Dialysis patients have therefore been granted high priority in the rollout of COVID19 vaccination campaigns in many countries. Several studies have reported an impaired humoral immunologic response to COVID19 vaccines2,3and a prolonged time to peak levels of severe adult respiratory syndrome coronavirus 2 (SARSCoV2) spike protein IgG antibodies in dialysis patients after COVID19 vaccination.2,4Optimal timing of vaccine doses has become an important topic of discussion. An improved immunologic response with prolongation of the time interval between dose one and dose two of Vaxzevria and Comirnaty has been explained in nonCKD populations.5,6An effect of variable time intervals between the first and second vaccine dose around the immunologic response has not yet been described in dialysis patients. We studied the effect of a prolongation of the interval between the first and second dose of COVID19 vaccines around the humoral immunologic response in haemodialysis patients. Most patients in the current study received two doses of mRNA vaccine (Comirnaty, BNT162b2, Pfizer/BioNTech or Spikevax, mRNA1273, and Moderna), but one individual received a combination FGF-18 of mRNA and a vectorbased vaccine (Comirnaty and Vaxzevria, ChAdOx1 and AstraZeneca). Manufacturers recommendations for the time between doses are 3 weeks for Comirnaty and 4 weeks for Spikevax. However, Swedish health authorities recommend dose intervals of 37 weeks for the Comirnaty vaccine and 47 weeks for the Spikevax vaccine. Thus, the time space between vaccine doses varied for patients treated at the participating dialysis centres in the current study. == 2. MATERIALS AND METHODS == == 2.1. Patients == The current crosssectional study was performed in five haemodialysis outpatient clinics in Central Sweden. All 198 maintenance haemodialysis patients were screened for inclusion. Patients who experienced received vaccination with two doses of COVID19 vaccine and timing of the second dose 28 weeks prior to study start were included in the study after written informed consent. Clinical and demographic data, including routine laboratory data within 4 weeks from blood sampling, for antiSARSCoV2 spike protein antibodies were retrieved from your Renal Information Management System (iRIMS), a quality registry, collecting dialysisrelated data prospectively. The study was approved by the Swedish Ethical Review Expert (202101442). == 2.2. Determination of antiSARSCoV2 spike protein antibodies == Blood samples for antiSARSCoV2 spike protein IgG antibodies were collected before a haemodialysis session. Titres of antiSARSCoV2 IgG antibodies in serum were decided using the EliA SARSCoV2Sp1 IgG test (Thermo Fisher Scientific, Phadia AB). The assay was performed according to the manufacturer’s instructions. Results <7 U/mL were considered unfavorable and antibody titres >204 U/mL were considered strongly positive according to manufacturer’s definition. == 2.3. Statistics == Data are offered as median (25th75th percentiles), frequencies or percentages, if not stated normally. A Pvalue below 0.05 was considered significant. Sulindac (Clinoril) Patients with a previous COVID19 diagnosis were compared with COVID19 nave patients. Furthermore, we compared patients according to the type of vaccine they had received. Sulindac (Clinoril) We applied the independentsamples median test for paired comparisons and for multiple comparisons with the Bonferroni correction for post hoc analyses. For correlation and regression analyses, continuous variables were standardized with outliers replaced by three standard deviations. Univariate correlations were calculated using Spearman’s Rho correlation coefficient, Sulindac (Clinoril) and multivariate analyses were.