Recent research compared the immune responses of patients with as well as without kidney failure, along with immunisation with different COVID-19 vaccines.

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The research revealed that the individuals on dialysis typically have an impaired response to vaccination. To better understand the predictors and dynamics of their antibody and cellular immune responses to different SARS-CoV-2 vaccines, a team led by An S De Vriese, MD, PhD (AZ Sint-Jan Brugge, in Belgium) prospectively evaluated responses at four or five weeks and again at eight or nine weeks after immunisation with the Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273) mRNA vaccines in 543 patients on hemodialysis and 75 individuals with normal kidney function. In the multicenter study, the researchers found an incomplete and delayed antibody response and a blunted cellular immune response to vaccination in patients on hemodialysis.

However, responses were substantially stronger with the mRNA-1273 vaccine than with the BNT162b2 vaccine (in both individuals with kidney failure and those with normal kidney function). The researchers believed that this may be due to the higher mRNA dose in the mRNA-1273 vaccine than in the BNT162b2 vaccine.

"These differences in immune response may translate into differences in vaccine effectiveness in vulnerable populations in the long-term when protective immunity is waning and in the battle against the Delta variant," said Dr De Vriese.

In addition, patients on hemodialysis who had prior COVID-19 infection, did not take immunosuppressive drugs, had higher serum albumin levels and lymphocyte counts, had previously responded to hepatitis B vaccination, and were on dialysis for only a short amount of time had higher antibody and cellular immune responses.

"We believe that a high-dose vaccine may be a valid strategy to improve SARS-CoV-2 vaccine effectiveness in hemodialysis patients. The most vulnerable patients--those who are using immunosuppressive drugs, have low serum albumin, a low lymphocyte count, are hepatitis B vaccine non-responders, or have a high dialysis vintage--may be good candidates for a third vaccine dose," said Dr De Vriese.