Nearly all cancer patients developed a good immune response to the mRNA vaccines against coronavirus disease (Covid-19) three to four weeks after their second dose, according to a new study. Cancer patients experience a higher burden of Covid-19 severity, complications, and mortality than the general population, and little data were available on vaccine efficacy in such high-risk patients.
An international team of researchers surveyed 131 patients with cancer to study the immune response to mRNA Covid-19 vaccines. Among them, 94% developed antibodies to the coronavirus while seven high-risk patients did not. The small group of patients who exhibited no response to the mRNA vaccines raised questions about how their protection against the virus will be addressed moving forward.
"We could not find any antibodies against the virus in those patients," said Dimpy P. Shah, MD, PhD, of the Mays Cancer Center, home to UT Health San Antonio MD Anderson. "That has implications for the future. Should we provide a third dose of vaccine after cancer therapy has completed in certain high-risk patients?"
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Which group is less likely to respond to Covid vaccines?
{{/usCountry}}Which group is less likely to respond to Covid vaccines?
{{/usCountry}}The median age of patients included in the survey was 63 and most of them (106) had solid cancers as against haematological malignancies (25). Pankil K. Shah, a co-lead author of the study, said that patients with haematological malignancies, such as myeloma and Hodgkin lymphoma, were less likely to respond to vaccination than those with solid tumours.
Among the patients, those receiving Rituximab, a monoclonal antibody used in the treatment of haematological cancers and autoimmune diseases, within six months of vaccination developed no antibodies. Patients on chemotherapy developed antibody response but it was muted compared to the general population.
“How that relates to protection against Covid-19, we don't know yet," Dr Dimpy Shah said.
The study suggests that patients with high-risk cancers should continue taking precautions even after being vaccinated. The findings of the study were published in the journal 'Cancer Cell'.
Limitations of the study
The highly transmissible Delta variant and other mutants were not examined in the study. The team also did not analyze the response of infection-fighting T cells and B cells in patients with cancer. The study population was 80% non-Hispanic white, 18% Hispanic and 2% Black, which means immune response among Black may vary in a bigger sample size.
"We recommend that future studies be done in Black, Asian and Hispanic patients, as well, to see if there are any differences in vaccination immune response," Dr Ruben Mesa, MD, FACP, executive director of the Mays Cancer Center said.
(With ANI inputs)