Single dose of BNT162b2 mRNA vaccine against SARS-CoV-2 induces high frequency of neutralising antibody and polyfunctional T-cell responses in patients with myeloproliferative neoplasms (preprint)

Encouraging results have been observed from initial studies evaluating vaccines targeting the novel beta coronavirus which causes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, concerns have been raised around the efficacy of these vaccines in immunosuppressed populations, including patients with haematological malignancy. Myeloproliferative neoplasms (MPN), in particular myelofibrosis (MF), are associated with heterogenous immune defects which are influenced by patient age, disease subtype and the use of cytoreductive therapies. Patients with a WHO defined diagnosis of an MPN presenting to our clinic were recruited following first injection of 30μg BNT162b2. A positive anti-S IgG ELISA was seen in 76.1% (16) of patients following vaccination with positive neutralising antibodies detected in 85.7% (18) of patients. A memory T cell response was observed in 80% (16) of patients, with a CD4+ T cell response in 75% (15) and a CD8+ T cell response in 35% (7). These results, for the first time, provide some reassurance regarding the initial immune response to the BNT162b2 vaccine amongst patients with MPN, with response rates similar to that observed in the general population.

Single dose of BNT162b2 mRNA vaccine against SARS-CoV2 induces neutralizing antibody and polyfunctional T-cell responses in patients with CML (preprint)

Patients receiving targeted cancer treatments such as tyrosine kinase inhibitors (TKIs) have been classified in the clinically extremely vulnerable group to develop severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including patients with Chronic Myeloid Leukaemia (CML) taking TKIs. In addition, concerns that immunocompromised individuals with solid and haematological malignancies may not mount an adequate immune response to a single dose of SARS-CoV-2 BNT162b2 (Pfizer- BioNTech) vaccine have been raised. We evaluated humoral and cellular immune responses after a first injection of BNT162b2 vaccine in 16 CML patients. Seroconversion and cellular immune response prior and after vaccination were assessed. By day 21 post-vaccination, anti-Spike IgG were detected in 14/16 (87.5%) of CML patients and all developed a neutralizing antibody response (ID50>50), including medium (ID50 of 200-500) or high (501-2000) neutralising antibodies titres in 9/16 (56.25%) patients. T cell response was seen in 14/15 (93.3%) evaluable patients, with polyfunctional responses seen in 12/15 (80%) patients (polyfunctional CD4+ response 9/15, polyfunctional CD8+ T cell response 9/15). These data demonstrate the immunogenicity of a single dose of SARS-CoV-2 BNT162b2 vaccine in most CML patients with both neutralizing antibodies and polyfunctional T-cell responses seen, in contrast to patients with solid tumour or lymphoid haematological malignancies.