Determinants of durable humoral and T cell immunity in myeloma patients following COVID-19 vaccination

Objective: To describe determinants of persisting humoral and cellular immune response to the second COVID-19 vaccination among patients with myeloma.Methods: This is a prospective, observational study utilising the platform. Participants reported their second and third COVID-19 vaccination dates. Myeloma patients had an Anti-S antibody level sample taken at least 21 days after their second vaccination and a repeat sample before their third vaccination.Results: 60 patients provided samples at least 3 weeks (median 57.5 days) after their second vaccination and before their third vaccination (median 176.0 days after second vaccine dose). Low Anti-S antibody levels (<50 IU/mL) doubled during this interval (p = .023) and, in the 47 participants with T-spot data, there was a 25% increase negative T-spot tests (p = .008). Low anti-S antibody levels prior to the third vaccination were predicted by lower Anti-S antibody level and negative T-spot status after the second vaccine. Independent determinants of a negative T-spot included increasing age, previous COVID infection, high CD4 count and lower percentage change in Anti-S antibody levels.Conclusions: Negative T-spot results predict low Anti-S antibody levels (<50 IU/mL) following a second COVID-19 vaccination and a number of biomarkers predict T cell responses in myeloma patients.