• Booster doses of mRNA vaccines containing the ancestral SARS-CoV-2 and omicronB.1.1.529 (BA.4 and BA.5) variant spike sequences are strongly recommended forindividuals at risk for severe Covid-19. However, patients undergoing hemodialysishave demonstrated inadequate immune responses to these vaccines, even afterreceiving four monovalent doses.

• To investigate the effectiveness of a fifth bivalent mRNA vaccine dose in thispopulation, 55 hemodialysis patients who had already received four SARS-CoV-2 vaccinations were monitored before and after their fifth vaccination.Results showed that patients with and without previous omicronbreakthrough infections experienced significant increases in anti-spike IgGconcentrations after the fifth vaccination. Furthermore, Patients withoutbreakthrough infections experienced a tremendous rise in infection-neutralizing capacity against both BA.4 and BA.5 and an increase in anti-spikeIgG avidity four weeks after vaccination. Neutralization activities against bothomicron BA.4 and BA.5 positively correlated with anti-spike IgGconcentrations and antibody avidity, suggesting that maintaining highantibody levels through periodic vaccinations is important.

• These findings support recommendations for patients undergoinghemodialysis to receive booster doses of bivalent mRNA vaccines, particularlyif they did not experience an omicron breakthrough infection.

REFERENCE-

Immunologic Effect of Bivalent mRNA Booster in Patients Undergoing Hemodialysis. N Engl J Med 2023; 388:950-952. DOI: 10.1056/NEJMc2216309