Alternative Vaccination Strategies Show Promise for Transplant Recipients with Impaired Immune Response

Strategic Insights -

Accumulating evidence has shown that solid organ transplant recipients have a significantly impaired responsiveness to standard SARS-CoV-2 mRNA-based vaccination, highlighting the need for alternative strategies to protect this vulnerable group. Researchers have been exploring different vaccination approaches, including the administration of a third dose of either heterologous ChAdOx1 (AstraZeneca) or homologous BNT162b2 (BioNTech) to kidney transplant recipients without a humoral response after two doses of BNT162b2. The study's findings suggest that a fraction of transplant recipients may benefit from triple vaccination, where seroconversion is associated with quantitative and qualitative changes of cellular immunity.

Key Takeaways:

  • 25 kidney transplant recipients without a humoral response after two doses of BNT162b2 received a third dose of either heterologous ChAdOx1 (AstraZeneca) or homologous BNT162b2, leading to seroconversion in 9/25 (36%) of patients.
  • The study highlights that a fraction of transplant recipients benefits from triple vaccination, where seroconversion is associated with quantitative and qualitative changes of cellular immunity.
  • ChAdOx1 and BNT162b2 vaccination showed a significant increase in frequencies of viral spike protein receptor binding domain specific B cells in humoral responders as compared to non-responders.
  • Portions of spike-reactive CD4+ T helper cells were significantly elevated in seroconverting patients.
  • The study emphasizes the urgent need for modified vaccination approaches for immunosuppressed patients.
  • The study's data suggest that overall frequencies of IL-2+, IL-4+ and polyfunctional CD4+ T cells significantly increased after the third dose, while memory/effector differentiation remained unaffected.

Statistics:

  • 25 kidney transplant recipients receiving a third dose of vaccine.
  • 9/25 (36%) of patients seroconverted until day 27 after the third vaccination.
  • 1 patient developed severe COVID-19 infection immediately after vaccination.
  • Frequencies of viral spike protein receptor binding domain specific B cells increased significantly in humoral responders (36-fold).
  • Portions of spike-reactive CD4+ T helper cells were significantly elevated in seroconverting patients (14-fold).
  • Overall frequencies of IL-2+, IL-4+ and polyfunctional CD4+ T cells increased after the third dose (2.5-4.5-fold).

Sources:

  • medrxiv.org/content/10.1101/2021.08.12.21261966v2
  • Keywords for this news article include: Biomedicine, Viral, Surgery, Vaccines, Virology, RNA Viruses, Vaccination, Immunization, Public Health, Transplantation, Organ Transplants, Kidney Transplants, Biological Products, Health and Medicine, Transplant Medicine, COVID-19/SARS-CoV-2 News from Preprints, Severe Acute Respiratory Syndrome Coronavirus 2.