The new results showed that over 90% of myeloma patients had an antibody response after two doses of a COVID-19 vaccine.
The prospective observational study, which the Blood Cancer UK Research Collaborative funded, investigates the impact of COVID-19 and the effectiveness of COVID-19 vaccines in myeloma patients.
Serum samples from 203 myeloma patients who had received two doses of either the Pfizer-BioNTech or Oxford-AstraZeneca COVID-19 vaccines were tested for antibodies against SARS-CoV2 nucleocapsid (N) or spike (S) protein.
92.7% (189/204) myeloma patients tested positive for anti-S protein antibodies (>50 iu/ml). This was a marked increase from the earlier phase of the study, which assessed anti-S protein antibodies levels after the first dose.
Samples from 158 myeloma patients were also tested for the presence of activated T cells using Interferon-Gamma Release Assay (IGRA). 60.1% of patients had a positive T cell response (>8 interferon gamma-releasing cells/106 peripheral blood mononuclear cells) after two COVID-19 vaccine doses.
6.3% (10/158) of myeloma patients tested negative for activated T cells and anti-S protein antibodies.
The study found that poor disease control predicts negative immune response. This suggests that robust disease control should be secured before vaccination or vaccination should take place before intensive treatment. This should be considered when scheduling booster vaccinations.
If patients had a partial response to myeloma treatment, relapsed, or received chemotherapy, they were more likely to have a lower level of anti-S protein antibodies and less likely to produce a T cell response.
Men were also more likely to develop lower levels of anti-S protein antibodies than women following vaccination, and anti-S protein antibody production reduced with age.
Whist these laboratory results are reassuring, the clinical implication of the observed immune responses, real-world infection rate, and the severity of infection remains unanswered.
Further investigation on how quickly the immune system of vaccinated patients responds to infection is needed to confirm the level of protection COVID-19 vaccines give myeloma patients.