Study shows two-dose COVID-19 vaccination is less effective for persons with CLL as compared to healthy controls.
The first research indicates that patients with CLL exhibited substantially lower immune response rates to the two-dose mRNA COVID-19 vaccination than healthy individuals of the same age. Because these vaccinations were not tested on patients with blood malignancies, who are at a higher risk of severe sickness and consequences from the virus, determining the vaccine’s efficacy in this population is crucial.
Only four out of ten CLL patients (39.5%) had a positive antibody-mediated response to the vaccination in this research; by contrast, all healthy individuals (controls) exhibited an immunological response.
Surprisingly, the study found that individuals with CLL had a wide range of immune responses depending on where they were in the cancer treatment process. Patients who were under active cancer therapy, for example, had a lower response rate to the vaccination than those who had completed treatment and were in remission, with 16 percent vs. 79 percent, respectively.
“Overall, the vaccine response rate was significantly lower than in the general population, which is most likely due to the presence of cancer and certain CLL treatments,” said Yair Herishanu, MD, associate professor of hematology and head of the CLL service at Israel’s Tel Aviv Sourasky Medical Center. “It appears that if you are untreated, in what we term a ‘wait and see’ situation, or if you do not have active illness, you will benefit more from the vaccination. Patients who reacted best were in remission, which makes logical because their immune systems had time to heal.”
Apart from not being on active CLL therapy, being younger, female, and having normal immunoglobin levels at the time of immunization all indicated a greater vaccine response rate. Patients with CLL exhibited lower antibody titers in addition to weaker qualitative antibody responses to the vaccination, indicating that, in addition to fewer patients responding to the vaccine, the strength of the response was also lower, stated Dr. Herishanu.
The immunological response to the vaccination was also examined dependent on which CLL therapy individuals got. Patients taking conventional targeted treatments like Bruton’s tyrosine kinase (BTK) inhibitors (ibrutinib or acalabrutinib) or a combination of venetoclax and anti-CD20 antibodies like rituximab had comparable poor response rates.
Notably, no patients who received anti-CD20 antibodies within a year of receiving COVID-19 vaccination responded. Dr. Herishanu said they couldn’t draw any conclusions about the effect on response because only five patients were on venetoclax monotherapy.
COVID-19 infection poses a significant risk of severe sickness and consequences in people with CLL and other blood malignancies, and despite low response rates, immunization against COVID-19 is strongly recommended. Patients with CLL who have finished treatment but have previously failed to react to COVID-19 vaccination may require an extra booster dose of the vaccine, according to the scientists, but this would need to be investigated.
“Even if response rates were not ideal, individuals with CLL should still obtain the vaccine,” Dr. Herishanu said. “If suitable, it may be better to do so before CLL therapy begins, but the disease itself may impact the response.” “It’s also critical to continue to take measures, such as wearing a mask, avoiding crowds, maintaining a social distance, and ensuring that close contacts are COVID-19-vaccinated.”
He and his colleagues will monitor these individuals for the next 12 months to see how many, if any, acquire COVID-19 infection as a result of the vaccine. They intend to evaluate the cellular immune response as well, as this study just looked at antibody response. This will give them a more full picture of how well patients are protected following vaccination.