New research has found that the weakened immune systems of patients with lymphoma may improve after they receive a third COVID-19 vaccination. Patients with lymphoma have defects in their immune system that restrict its response to vaccination; despite this, a study published by Lim et al in Nature Cancer found improvements in antibody and T-cell responses after a third vaccine dose, except in patients who had recently received anti-CD20 therapy.
“Despite the gradual lifting of COVID-19 restrictions worldwide, a cloud continues to hang over immunosuppressed patients, who may not develop protective immune responses after vaccination,” explained first study author Sean Lim, MBChB, MRCP, PhD, FRCPath, Associate Professor and Honorary Consultant in Haematological Oncology at the University of Southampton. “In particular, individuals with hematologic malignancies are at greater risk of severe COVID-19 … even if they have been vaccinated,” she continued.
Dr. Lim and her team collected blood samples from 457 adult patients with lymphoma; when possible, these were taken prior to their first vaccination with either the Oxford-AstraZeneca or Pfizer-BioNTech vaccine, then 4 weeks after the first dose, 2 to 4 weeks and 6 months after the second dose, and 4 to 8 weeks after the third dose.
The study aimed to evaluate the strength of the immune system’s response to the vaccines and to help predict how effective the vaccine could be for patients with lymphoma. To achieve this, the scientists measured the ability of antibodies in the blood samples to prevent the viral spike protein from binding to ACE2 proteins, which are the virus’s key point of entry into the human body. They also measured the response of T cells when stimulated by the viral spike.
Response to Third Vaccination
The results showed that while just over half of patients undergoing active cancer treatment had no detectable antibody levels after the second vaccination, T-cell responses could be detected in about two-thirds of all patients. After a third dose, 92% of patients who were not undergoing anti-CD20 treatment showed improved antibody responses, compared to 17% who were receiving that treatment.
“We observed a good link between the level of antibodies in the blood samples and how well these antibodies blocked the virus from binding to the ACE2 protein,” said Dr. Lim. “This suggests that the antibodies induced in patients with lymphoma perform similarly to those in healthy donors.”
A key question for patients with suppressed immunity systems is whether there is a connection between antibody and cellular responses and the risk of infection, hospitalization, and death from COVID-19. The research team will therefore follow up this research with further analysis into the clinical outcomes of patients in this study who were infected with COVID-19.