Cellular and humoral immunity following two AZD1222 and two booster vaccinations in hemodialysis patients.

BACKGROUND

Dialysis patients are vulnerable to SARS-CoV-2 infection and subsequent complications. However, the vaccine-induced immunity, especially against new variants, following two AZD1222 and two booster doses in hemodialysis patients remain largely unknown.

METHODS

In this observational cohort study, we monitored immune responses in 127 hemodialysis patients receiving the 3rd and 4th vaccinations until three months after the 4th immunization. Humoral and cellular immunity were assessed by anti-SARS-CoV-2 receptor-binding domain(RBD) antibody, neutralizing antibodies against the ancestral virus, delta, omicron BA.1 and BA.2 and SARS-CoV-2 specific IFN-γ releasing assay (Covi-FERON).

RESULTS

The primary series and the fourth dose predominantly consisted of two-dose AZD1222 and mRNA-1273, respectively. The most common vaccines chosen for the third dose was mRNA-1273(n = 84), following by BNT 162b2(n = 38). Anti-RBD antibody increased to 13803.8 and 18197U/ml after the 3rd and 4th vaccination, respectively, but dropped to 8709.6U/ml three months after the fourth vaccination. One month after the fourth vaccination, 99 %,98 %,51.5 % and 93.9 % participants had neutralizing antibodies against the ancestral virus, delta, omicron BA.1 and BA.2, respectively. 87.9 % and 81.8 % patients reacted to the ancestral or alpha and beta or gamma spike antigens in Covi-FERON, respectively, after four vaccinations. Higher Covi-FERON reactions were associated with increased IL-2 and IL-4 secretion. In linear mixed effect models, mRNA-1273 as the third vaccination was associated higher anti-RBD antibody titers and higher neutralization against the ancestral virus and delta compared with BNT162b2 but with higher mild adverse events following vaccination.

CONCLUSIONS

Two AZD1222 and two mRNA booster doses confer substantial humoral and cellular immunity against variants including omicron in hemodialysis patients.