Reassuring Findings on Bivalent COVID Booster in Hemodialysis Patients

Anti-spike IgG concentrations against BA.4/5 significantly increased in patients with end-stage renal disease (ESRD) following a bivalent booster, particularly in those without a prior Omicron infection, a case series from Germany found.

The study looked at 55 ESRD patients on hemodialysis who had received four prior doses of a monovalent vaccine, including about a third with prior Omicron breakthrough infections.

From 2 weeks before to 2 weeks after a fifth dose with a bivalent mRNA vaccine, anti-spike IgG concentrations increased by a factor of 2.5 for patients with a prior infection and by a factor of 7.3 for those without a previous infection, reported Martina Prelog, MD, of the University Hospital Würzburg in Germany, and colleagues.

Across all patients, anti-spike IgG concentrations were increased by a factor of 4.9 against BA.4 and by a factor of 3.3 against BA.5.

Anti-spike IgG avidity, which can correlate with protection, increased by 17% at 4 weeks (P<0.001), the group detailed in a correspondence to the New England Journal of Medicine.

"In particular, patients who did not have previous breakthrough infection immunologically benefited from a bivalent mRNA booster: despite having lower anti-spike IgG concentrations before the fifth vaccination, they had a significant increase after the fifth vaccination, such that their concentrations matched those in persons with hybrid immunity due to Omicron breakthrough infection," wrote Prelog and co-authors.

Patients on dialysis are among the most vulnerable populations for severe illness from COVID-19, with one study in Medicare patients pointing to mortality rates as high as 26% following infection.

Prior research has shown that patients on hemodialysis are more likely to have inferior cellular and humoral immunity against emerging COVID-19 variants, even with multiple prior doses of vaccine.

In the current study, neutralization activities against BA.4/5 after the bivalent dose positively correlated with anti-spike IgG concentrations, antibody avidity, and neutralization activity before receipt of the booster.

"The high dependency of neutralization activity against Omicron BA.4 and BA.5 on baseline anti-spike IgG concentrations and binding activity before booster vaccination corroborates the concept that antibodies should be maintained at high levels by means of periodic vaccinations," noted Prelog and colleagues. "The results may be of particular importance for persons at risk for severe disease, such as patients undergoing hemodialysis, and support recommendations that these patients should receive booster doses of bivalent mRNA vaccines, particularly if they have no hybrid immunity from an Omicron breakthrough infection."

To evaluate anti-spike IgG concentrations following a bivalent vaccine in ESRD patients on hemodialysis, the researchers recruited 55 patients, all of whom had four previous doses of COVID vaccine. In the 18 patients with a previous Omicron breakthrough infection, the average age was 73 years and 17% were women. In the 37 patients without a breakthrough infection, mean age was 68 years and 46% were women.

The researchers looked at anti-spike IgG concentrations 6 weeks and 2 weeks before vaccination, as well as 2 weeks and 4 weeks after vaccination.

Only ESRD patients on hemodialysis with normal total serum IgG levels, normal leukocyte counts, and without pharmacologically relevant immunosuppressants were included.

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