COVID-19 vaccines trigger weaker immune response in B-cell CLL patients

Due to the immunosuppression associated with B-cell chronic lymphocytic leukaemia (CLL), immune responses elicited after the first and second dose of vaccines for the coronavirus disease 2019 (COVID-19) are substantially reduced in these patients, a recent study has found.

“This work supports the need for optimization of vaccination strategy in patients with CLL including the potential utility of booster vaccines,” the researchers said.

The study included 299 CLL patients (median age 69 years, 53 percent men) who had received their first and/or second doses of COVID-19 vaccines. An electrochemiluminescence immunoassay was used to measure antibody response. A parallel group of 93 age-matched healthy donors was also included as a control.

Eighty-six venepuncture serum samples were available for antibody response analysis in patients undergoing extended-interval vaccination. At 5–6 weeks after the initial dose, only 29 of these samples tested positive for an anti-spike antibody response, corresponding to an overall response rate of 34 percent. This was 2.8-fold lower than healthy controls, who showed a 94-percent response rate.

Median antibody titres were likewise lower in CLL patients, who showed 104-fold lower concentrations than controls (0.4 vs 41.6 U/mL; p<0.0001).

Responses remained low in patients even after the second dose, the analysis for which included 12 serum samples. Spike-specific antibody response was detected in 75 percent of samples from CLL patients, as opposed to 100 percent of controls. Titres were likewise significantly attenuated, with patients showing 74-fold lower concentrations (53 vs 3,900 U/mL; p<0.0001).