International Journal of Infectious Diseases (Feb 2024)

Long-term efficacy of the peptide-based COVID-19 T cell activator CoVac-1 in healthy adults

  • Claudia Tandler,
  • Jonas S. Heitmann,
  • Tanja M. Michel,
  • Maddalena Marconato,
  • Simon U. Jaeger,
  • Christian M. Tegeler,
  • Monika Denk,
  • Marion Richter,
  • Melek Tutku Oezbek,
  • Yacine Maringer,
  • Sarah M. Schroeder,
  • Nicole Schneiderhan-Marra,
  • Karl-Heinz Wiesmüller,
  • Michael Bitzer,
  • Natalia Ruetalo,
  • Michael Schindler,
  • Christoph Meisner,
  • Imma Fischer,
  • Hans-Georg Rammensee,
  • Helmut R. Salih,
  • Juliane S. Walz

Journal volume & issue
Vol. 139
pp. 69 – 77

Abstract

Read online

Objectives: T cell immunity is key for the control of viral infections including SARS-CoV-2, in particular with regard to immune memory and protection against arising genetic variants. Methods: We recently evaluated a peptide-based SARS-CoV-2 T cell activator termed CoVac-1 in a first-in-human trial in healthy adults. Here, we report on long-term safety and efficacy data of CoVac-1 until month 12. Results: CoVac-1 is well tolerated without long-term immune-related side effects and induces long-lasting anti-viral T cell responses in 100% of study participants, with potent expandability of clusters of differentiation (CD4+) and CD8+ T cells targeting multiple different CoVac-1 T cell epitopes. T cell responses were associated with stronger injection site reaction. Beyond induction of T cell immunity, 89% of subjects developed CoVac-1-specific immunoglobulin G antibodies which associated with the intensity of the T cell response, indicating that CoVac-1-specific CD4+ T cells support the induction of B-cell responses. Vaccination with approved COVID-19 vaccines boosted CoVac-1-specific T cell responses. Overall, a low SARS-CoV-2 infection rate (8.3%) was observed. Conclusion: Together, a single application of CoVac-1 elicits long-lived and broad SARS-CoV-2-specific T cell immunity, which further supports the current evaluation of our T cell activator in patients with congenital or acquired B-cell defects.

Keywords