Blood cancer patients less protected by Covid-19 vaccination

Blood cancer patients are at increased risk of severe disease and death from Covid-19 and are less likely to be protected by Covid-19 vaccination, according to UCLH and UCL research.

Patients with blood cancers affecting B cells – a type of white blood cell – have a particularly high risk, according to the research led by UCLH consultant haematologist Prof Emma Morris and published on the pre-print server medRxiv.

The COV-VACC study, funded by our BRC,  is evaluating the immune response to Covid-19 vaccination in patients with B cell malignancies who have received either the Pfizer-BioNTech or Oxford-AstraZeneca vaccines. 50% of participants were receiving anti-cancer therapy at the time of vaccination. This interim analysis reports results from the first 55 study participants.

 Study findings – which have not yet been peer reviewed – suggest 2 important things: (1) that following one dose of the vaccine only 36% of patients made an antibody response to the vaccine, which increased slightly to 42% after the second vaccine dose, which is lower than would be expected in the general population; and (2) in the minority of patients who actually made an immune response to the vaccine – their antibodies were less good at neutralising the SARS-CoV-2 virus in laboratory tests (only 57% of antibody positive patients had functional, ‘protective’ antibodies after full vaccination).   

Participants vaccinated more than 6 months after completing their cancer therapy were significantly more likely to develop antibodies, which could neutralise the SARS-CoV-2 virus than those within 6 months of treatment or on active treatment.

The study team said the data has important implications for patients with B cell malignancies and that urgent consideration should be given to revaccinating patients with B-cell cancers after completion of anti-cancer treatment as large numbers currently remain at high risk of infection with the increasing transmission of SARS-CoV-2 in many countries.