FC086: Improved Immunologic Response to COVID-19 Vaccine with Prolonged Dosing Interval in Hemodialysis Patients

Abstract

BACKGROUND AND AIMSVaccination against coronavirus disease 2019 (COVID-19) can reduce disease incidence and severity. Dialysis patients demonstrate a delayed immunologic response to vaccines. We determined factors affecting the immunologic response to COVID-19 vaccines in hemodialysis patients.METHODAll patients within a Swedish hemodialysis network, vaccinated with two doses of COVID-19 vaccine 2–8 weeks before inclusion, were eligible for this cross-sectional study. Severe adult respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein antibody levels were determined by the EliA SARS-CoV-2-Sp1 IgG test (Thermo Fisher Scientific, Phadia AB) and related to clinical and demographic parameters. Eighty-nine patients were included.RESULTSPatients were vaccinated with two doses of Comirnaty (BNT162b2, 73%) or Spikevax (mRNA-1273, 23.6%). Three patients received combinations of different vaccines. Response rate (antibody titres >7 U/mL) was 89.9%, while 39.3% developed high antibody titres (>204 U/mL), 47 (43–50) days after the second dose. A previous COVID-19 infection associated with higher antibody titres [median (25th–75th percentile) 1558.5 (814.5–3763.8) U/mL versus 87 (26–268) U/mL; P = 0.002], while the time between vaccine doses did not differ between groups (P = 0.7). Increasing SARS-CoV-2 antibody titres were independently associated with increasing time between vaccine doses, decreasing serum calcium levels and previous COVID-19 (Table 1).CONCLUSIONIn conclusion, a longer interval between COVID-19 mRNA vaccine doses, lower calcium and a previous COVID-19 infection were independently associated with a stronger immunologic vaccination response in hemodialysis patients. While the response rate was good, only a minority developed high antibody titres 47 (43–50) days after the second vaccine dose.Table 1.Multiple regression of predictors of SARS-CoV-2 spike IgG response to COVID-19 vaccinesRegression coefficient(95% CI)P(Constant)0.015 (–0.507 to 0.537)0.95Type of vaccine–0.194 (–0.566 to 0.179)0.30Sodium (1 SD)–0.154 (–0.309 to 0.001)0.051Calcium (1 SD)–0.233 (–0.4 to –0.067)0.007Treatment time (1 SD)–0.05 (–0.234 to 0.133)0.586Bodymass index (1 SD)0.104 (–0.086 to 0.294)0.279IDBWG (1 SD)0.118 (–0.042 to 0.278)0.145Kt/V (1 SD)0.009 (–0.159 to 0.177)0.915Vaccine interval (1 SD)0.241 (0.039 to 0.443)0.02Interval first dose to sample (1 SD)0.027 (–0.142 to 0.197)0.750Previous COVID-191.078 (0.56 to 1.596)<0.001