Efficacy of Comirnaty Vaccine in Lymphoma and Myeloma Patients Post-ASCT

Overview

In a cohort of 64 hematological malignancy patients post-autologous stem cell transplantation (ASCT), 87% developed a humoral immune response to the Comirnaty vaccine. Vaccination failure was significantly associated with ongoing therapy rather than ASCT status, and seronegative patients exhibited reduced spike-specific T-cell responses.

Background

Patients with hematological malignancies (HMs) experience higher COVID-19 mortality rates and variable immune responses to SARS-CoV-2 infection and vaccination. mRNA vaccines, including Comirnaty, are recommended for these high-risk patients. However, immune responses post-vaccination, especially in those undergoing treatments like ASCT, remain heterogeneous and require detailed evaluation. This study prospectively assessed humoral and cellular immunity following vaccination in HM patients treated with ASCT.

Data Highlights

Key Findings

• Overall, 87% of patients developed a positive humoral response (anti-SARS-CoV-2 IgG >33.8 BAU/ml) after two doses of Comirnaty.
• Only 3% of patients vaccinated after ASCT as last treatment failed to seroconvert, compared to 21% in those without ASCT as last treatment.
• Being on active therapy at vaccination was strongly associated with vaccination failure (multivariate OR 49.45; P = 0.007).
• There was a positive correlation between absolute lymphocyte count and antibody titer magnitude (ρ = 0.48; P = 0.0008), but no association with seroconversion failure.
• Seronegative patients showed significantly lower spike-specific CD8+IFNγ+ and CD4+ T-cell responses by FACS analysis compared to seropositive patients.
• ELISpot assays indicated fewer spike-specific IFNγ-producing T-cells in seronegative patients (50%) versus seropositive patients (75%).

Clinical Implications

These findings support the efficacy of the Comirnaty vaccine in eliciting humoral and cellular immunity in HM patients post-ASCT, particularly when vaccination occurs after completion of therapy. Active treatment at the time of vaccination markedly reduces vaccine responsiveness, underscoring the importance of timing vaccination relative to therapy. Monitoring both antibody and T-cell responses may help identify patients at risk of inadequate protection.

Conclusion

The Comirnaty vaccine induces robust immune responses in most lymphoma and myeloma patients post-ASCT, with ongoing therapy representing a key factor in vaccination failure. Strategic vaccination timing and immune monitoring are critical to optimize protection in this vulnerable population.

References

1. Passamonti et al. 2020 -- COVID-19 mortality in hematological malignancies
2. Italian National Vaccination Plan 2021 -- Prioritization of hematological malignancy patients
3. ClinicalTrials.gov NCT04878822 -- Study on immune response to SARS-CoV-2 vaccination in hematological malignancies