Safety and Efficacy of the COVID-19 Vaccine in Kidney Transplant Recipients.

Background: Kidney transplant recipients appear to be at high risk for critical coronavirus disease 2019 (COVID-19) illness. They are considered a priority for COVID-19 vaccination. Only a few studies report on the safety and efficacy of the COVID-19 vaccine in these patients.

Methods: In this prospective observational study, we measured anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) spike-specific IgG post first and second COVID-19 mRNA vaccines in 113 kidney transplant recipients and compared them to 62 healthy volunteers.

Result: After the first COVID-19 vaccine, SARS-CoV-2-specific antibodies were undetectable in 38.9% of kidney transplant recipients, and after the second, it remained undetectable in 12.4%. SARS-CoV-2-specific antibodies were significantly lower in kidney transplant recipients. The average antibody titer after the first vaccine was 1243.6±4137.5 in kidney transplant recipients compared to 20012.2±44436.4 in the controls after the first dose (P=0.002), and 7965.5±12431.3 versus 82891.3±67418.7, respectively, after the second dose (P <0.001). The immune response to the COVID-19 vaccine seemed to be influenced by mycophenolate dose in kidney transplant recipients and pre-vaccination infection.

Conclusion: Kidney transplant recipients are prone to have attenuated antibody responses (anti-spike IgGs) to mRNA COVID-19 vaccines. Patients on mycophenolate mofetil (2 gm daily) had significantly lower SARS-CoV-2 spike-specific IgG levels as compared to patients on no or reduced dose of mycophenolate. Hence, kidney transplant recipients need to continue all infection control precautionary measures against COVID-19 infection and should be considered a priority for a third COVID-19 vaccine.