Prospective, Cohort, Non-interventional, Single-center Clinical Study of Immune Response Status to SARS-CoV-2 / Covid-19 Vaccination in Patients With Haematological Malignancies.

Covid-19 is associated with a mortality rate of 33-37% in patients with hematological malignancies (Passamonti et al, 2020; Garcia-Suarez et al, 2020). Currently, there is little information on the serological response following SARS-Cov-2 infection in this specific population.

At present, the anti-SARS-CoV-2 vaccination represents the most effective strategy for the prevention of Covid-19. The anti-SARS-CoV-2 vaccines currently approved by the European Medicines Agency (EMA) and the Italian Medicines Agency (Agenzia Italiana del Farmaco, AIFA) are: the BNT162b2 SARS-Cov-2 (Pfizer-BioNTech, Comirnaty) vaccine, the mRNA-1273 SARS-Cov-2 (Moderna) vaccine, the ChAdOx1 nCoV-19 (Vaxzevria) vaccine, and the Ad26.COV2.S (Janssen) vaccine.

The double-dose regimen of Pfizer-BioNTech vaccine showed 95% efficacy at preventing Covid-19 (Polack et al, 2020), the double-dose regimen of Moderna vaccine showed 94.1% efficacy (Baden et al, 2021), the double-dose regimen of Vaxzevria vaccine showed 70.4% efficacy (Voysey et al, 2021), while the single-dose regimen of Janssen vaccine was found to be 66.1% effective (Sadoff et al, 2021).

The Italian national Covid-19 vaccination plan included patients with active malignancies in the second priority group, recognizing the importance of protecting this vulnerable population from SARS-Cov-2 infection. Since vaccine clinical trials excluded patients with malignancies and patients undergoing immunosuppressive therapies, the immunological response to anti-SARS-CoV-2 vaccines in these patients is currently unknown.

In this prospective, cohort, non-interventional study, our objective is to evaluate both the humoral and the cellular immune response to anti-SARS-CoV-2 vaccination in adults with hematological malignancies. For each patient the immune response will be evaluated after a minimum of 28 days from the completion of the vaccination regimen. Then, it will be reassessed after 6 and 12 months. In our center, the humoral immune response will be assessed by using the DiaSorin's LIAISON SARS-CoV-2 S1/S2 IgG test, which quantifies the level of anti-SARS-CoV-2 IgG antibodies that are active against the S1 and S2 subunits of the S protein. The cell-mediated immune response will be assessed on peripheral blood cells through a phenotypic and functional analysis by flow cytometry and through the ELISPOT test. Each patients will sign an informed consensus for the participation. The total duration of the study will be 24 months.