COVID-19 Vaccine Efficacy in Solid Organ Transplant Recipients

Strategic Insights -

Researchers from the University of Maryland have analyzed the humoral immune responses of solid organ transplant recipients to SARS-CoV-2 vaccination, revealing an increased risk of COVID-19-related mortality in these patients. The team found that a third vaccine dose resulted in improved antibody responses against most SARS-CoV-2 variants, except the omicron variant, where antibody responses and neutralizing activity remained suboptimal. This study highlights the need for further research on vaccination strategies for solid organ transplant recipients.

Key Takeaways:

  • Solid organ transplant recipients (SOTR) receiving post-transplant immunosuppression show increased COVID-19-related mortality.
  • Only a small subgroup of SOTR is able to generate functional antibodies after an initial vaccine series.
  • A third vaccine dose resulted in dramatically improved antibody responses against all SARS-CoV-2 variants, except omicron.
  • The omicron variant showed significantly lower antibody titers after the third dose, with reduced neutralizing activity.
  • Antimetabolites in immunosuppression negatively impacted antiviral immunity in SOTR.
  • IgG levels were lower in SOTR than controls, but antibody titers against microbial recall antigens were higher.

Statistics:

  • 60.3% of SOTR showed no measurable neutralization after the initial vaccination series.
  • 18.9% of SOTR demonstrated neutralizing activity of 90% after the initial vaccination series.
  • A third vaccine dose resulted in an increase in anti-SARS-CoV-2 antibody titers and neutralizing activity across alpha, beta, and delta variants.
  • However, antibody titers against the omicron variant were significantly lower after the third dose.

Sources:

  • Humoral Immunity Against Sars-cov-2 Variants Including Omicron In Solid Organ Transplant Recipients After Three Doses of a Covid-19 Mrna Vaccine. Clinical & Translational Immunology, 2022;11(5).
  • Study Data from University of Maryland Provide New Insights into COVID-19 (Humoral Immunity Against Sars-cov-2 Variants Including Omicron In Solid Organ Transplant Recipients After Three Doses of a Covid-19 Mrna Vaccine). Vaccine Weekly. June 1, 2022; p 1070.