Medical Health Cluster

1 abril, 2022

Timing of COVID-19 Vaccination Crucial for Blood Cancer Patients

The timing of treatment in relation to vaccination is the strongest predictor of COVID-19 vaccine antibody response say the researchers of a new study.

For their study, published in Nature Cancer, researchers from the University of Southampton led a UK multicentre prospective observational study (PROSECO) evaluating COVID-19 vaccine responses in individuals with lymphoma. The researchers described how they “aimed to evaluate the robustness and persistence of immune responses to vaccination, define factors associated with impaired immune responses and assess the incidence of COVID-19 infections in vaccinated individuals”.

The authors highlighted how individuals with cancer have increased morbidity and mortality from COVID-19 infection, this being “most apparent in patients with haematological malignancies”, who they said have a reported odds ratio of 1.57 to 3.3 in developing severe COVID-19 compared to patients with solid tumours.

Dr Sean Lim, associate professor and honorary consultant in Haematological Oncology at the University of Southampton, who led the research, said: “Individuals with haematological malignancies are at greater risk of severe COVID-19 disease even if they have been vaccinated.”

Cloud Continues to Hang Over Immunosuppressed Patients

The study aimed to evaluate the strength of the immune system’s response to the vaccines and to help predict how effective COVID-19 vaccination could be for lymphoma patients. To investigate this the researchers measured the ability of antibodies to prevent the viral spike protein from binding to ACE2 proteins, and also measured the response of T-cells when stimulated by the viral spike.

“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 Dr Lim.

Blood samples from 457 adult lymphoma patients – Hodgkin lymphoma (71), aggressive B-cell non-Hodgkin lymphoma (149), indolent B-NHL (221), and peripheral T-cell/natural killer (NK) cell lymphoma (16) – were collected before they received their first vaccination of either the Oxford-AstraZeneca or BioNTech Pfizer vaccines, four weeks after the first dose, 2-4 weeks and 6 months after the second dose, and 4-8 weeks after the third dose. Blood samples were then analysed for antibodies to SARS-CoV-2 and T-cell responses to the spike protein.

Urgent Need for COVID-19-Specific Immune Response Monitoring

The results showed that whilst just over half (52%) 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 (63%) of all patients. After a third dose, 92% of patients who were not undergoing anti-CD20 treatment for their cancer showed improved antibody responses, compared to 17% who were receiving that treatment. The authors highlighted how “60% of patients on anti-CD20 therapy had undetectable antibodies following full vaccination within 12 months of receiving their anticancer therapy”.

“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.”

The authors explained how they had demonstrated that the strongest predictor of antibody vaccine response in patients with lymphoid malignancies is the timing of treatment in relation to vaccination, regardless of the number of doses administered.

They said their results “emphasised the urgency of careful monitoring of COVID-19-specific immune responses to guide vaccination schemes in these vulnerable populations”.

Créditos: Comité científico Covid

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