The study, funded by Blood Cancer UK, investigated the effectiveness of COVID-19 vaccines in preventing hospitalisations and death due to COVID-19 infection, as well as potential side effects, for people living with blood cancers. The researchers analysed data from QResearch, a multi-million-person health record database, to compare outcomes for people with blood cancer to those of the general population.
As we manage COVID-19 without social distancing and mask mandates, people with blood cancers, such as leukaemia, lymphoma and myeloma, are known to be at higher risk from severe outcomes from COVID-19 compared to the general population. Their compromised immune systems also lead to poorer antibody responses to vaccination.
The study found that the vaccines were highly effective against death from COVID-19 for people with blood cancer, offering protection comparable to that in the general population. After two vaccine doses, those with blood cancer had 92% protection and after a booster dose they had 70% protection.
Despite this, the researchers found that vaccination was less effective at preventing COVID-19-related hospitalisation for people with blood cancer. Following two doses, vaccine effectiveness against hospitalisation peaked at 72% in the first two weeks after vaccination but dropped to levels below 50% within six months, likely due to the nature of blood cancers, treatments and the effect both have on the immune system. After a booster dose, protection rose to 64% against hospitalisation. In comparison, two doses provided over 80% protection against hospitalisation in the general population, only dropping below 50% after six months.
The study also analysed the risk of potential vaccine side effects in the 28 days after vaccination and found no evidence that people with blood cancer were at increased risk compared to the general population.
“This study provides robust evidence that COVID-19 vaccines are safe and effective for people with blood cancers, despite their vulnerable immune systems,” said Emma Copland, a Research Fellow at the Nuffield Department of Primary Care Health Sciences, University of Oxford, and lead author of the study. “The findings have important implications for people living with blood cancer as research into the effects of COVID-19 vaccinations for them has thus far has been limited, despite being prioritised for vaccination in the UK since December 2020. The results of this study highlight the importance of COVID-19 vaccination in people with blood cancer, and the need for future research to include this vulnerable group.”
Dr Rubina Ahmed, Director of Research, Policy and Services from Blood Cancer UK, said: “People with blood cancer are particularly vulnerable to severe illness from COVID-19. The lack of previous research has meant people with blood cancer have faced uncertainty about the levels of protection COVID-19 vaccines give. These new findings from research Blood Cancer UK funded demonstrate that COVID-19 vaccines are safe and provide protection from the worst outcomes of infection. The work provides good evidence that people with blood cancer should receive the vaccine and subsequent booster doses.”
The findings, conclude the authors, can be used to guide policy and ensure that those with blood cancer in the UK are given effective support and treatment against COVID-19.
Read the full paper: 'Effectiveness and safety of COVID-19 vaccination in people with blood cancer' in the European Journal of Cancer.