Medical Technology

COVID-19 Vaccine Responses Vary Among Hematological Malignancies

Key Takeaways

  • The main outcome was the rate at which a COVID-19 vaccine produced seropositivity. Secondary outcomes included rates of seropositivity following 1 dose, rates for positive neutralizing antibody (nAb) and cell responses and adverse events.

  • Two thirds of patients (67%) with hematological malignancies were seropositive after 2 doses of a COVID-19 vaccine.

  • The most at-risk patients were those suffering from chronic Lymphocytic Leukemia (CLL) and those who are currently undergoing active anti-CD20 and targeted therapy.

  • The authors called for urgent breakthroughs for the treatment of patients at high risk who are not immune to vaccination.

Why this is important

  • More than 80% of patients with cancers of the hematological spectrum require hospitalization following the infection with COVID-19. more than 50% suffer from severe disease. The mortality rate can be to as high as 40 percent to 30%.

  • Patients with hematological malignancies were not excluded from clinical trials involving vaccines.

Study Design

  • The study was an analysis of a meta-analysis of 44 studies of 7064 patients. It included 2331 patients who were analyzed after a first dose and 4733 after the second dose of any COVID-19 vaccine.

  • The authors analyzed data on humoral and cellular immune responses following vaccination. A humoral response (seropositivity) was defined as levels that could be detected SARS-CoV-2-specific spikes/receptor binding-domain-specific G. (IgG). A cellular response was defined as an increase in the number of SARS-CoV-2-specific CD4+/CD8+ T cells.

  • The Newcastle-Ottawa Scale was used to determine the risk of bias.

Key Results

  • After two COVID-19 vaccination doses The rate of seropositivity was 61% among patients with hematology, and 67% in comparison studies. After a single dose the rates were 51% and 37%, respectively.

  • Hematologic malignancy was associated with a lower probability of being seropositive than healthy controls after two doses (odds ratio 0.05; P < .01) and after 1 dose (OR, 0.10; P .01).

  • In 10 studies (22%), the rate of at least one local or systemic adverse event was reported. The average rate of at least one adverse reaction was 36% after 2 doses and 39% following one dose.

  • Patients with acute leukemia as well as myelodysplastic disorders had the highest seropositivity rates (93%) followed by myeloproliferative as well as chronic meeloid leukemia (87%-88%) respectively), and CLL patients had the lowest (51%).

  • Subgroup analyses revealed the lowest levels of seropositivity among patients receiving active treatment (28%) specifically, prior or ongoing treatment for 12 months with anti-CD20 antibodies (19%) targeted therapies (35 percent), and after CAR-T therapy (31 percent). Patients who did not receive active therapy had higher seropositivity rates (61 percent), and for a period of 12 or more months after anti-CD20 therapy was completed (62 percent).


  • Due to the substantial variation in the clinical and statistical characteristics of the studies that are included the quality of the findings is not high.

  • The data on immune responses do not necessarily reflect the effectiveness or clinical efficacy of vaccination.

Study Disclosures

  • Authors have received research funding and honoraria from Pfizer, Merck Sharp and Dohme, CSL Behring, and Sanofi, as well as research grants from Gilead.

This is a synopsis of a preprint research of the study”Immunogenicity of COVID-19 vaccines in patients with cancer of the haematological type: A systematic review and meta-analysis” conducted by Benjamin W. Teh, PhD who is a researcher at Peter MacCallum Cancer Centre and the University of Melbourne, Australia. It was published on prior to peer review and is made available to you by Medscape.

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