A meta-analysis of 44 studies involving 7064 patients found that around 67% of patients with hematological malignancies were seropositive after receiving two doses of a COVID-19 vaccine.

Patients at highest risk of nonresponse were those who had chronic lymphocytic leukemia (CLL) and those who were being treated with active targeted and anti-CD20 therapies.

The analysis included 2331 patients assessed after first vaccine dose and 4733 evaluated after the second dose of a COVID-19 vaccine. The humoral and cellular immune responses after vaccination were analyzed. The rate of seropositivity in hematological malignancy patients was 61% after two vaccine doses, and 67% in comparator studies. After one dose, the corresponding rates were 51% and 37%, respectively. Hematologic malignancy was found to be tied to lower odds of achieving seropositivity compared to healthy controls after 2 doses (odds ratio 0.05; P < .01), and after 1 dose (OR, 0.10; P < .01). Seropositivity rates after two vaccine doses appeared to be the highest among patients with acute leukemia and myelodysplastic syndromes (93%), followed by myeloproliferative neoplasm and chronic myeloid leukemia (87%-88%). The rates of seropositivity were the lowest in CLL patients (51%)… (Medscape)