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About 25% of patients with blood cancer did not produce antibodies after being vaccinated against COVID-19.
Patients with blood cancer may not get the same protection from COVID-19 vaccination as the general population, as a recent study found that about one in four patients did not have detectable antibodies after getting the vaccine.
“While the vaccines were tested in the healthy population, they were approved based on safety, the ability to make an antibody against the virus that causes COVID-19 and protection against serious COVID-19 infection,” Dr. Gwen Nichols, chief medical officer of The Leukemia & Lymphoma Society (LLS) said in an interview with CURE®.
Nichols was involved in research conducted by the LLS that involved 1,445 patients with blood cancer who had antibodies – which the body develops after vaccination to fight off the virus that causes COVID-19 – measured at least two weeks after receiving their second dose of the Moderna or Pfizer mRNA vaccine.
The study was important for a couple of reasons. First, the clinical trials investigating the COVID-19 vaccines excluded patients with cancer, citing safety concerns, and second, people with blood cancer tend to have a higher rate of serious infection and death after being diagnosed with COVID-19.
“Almost everyone (in the study) made antibodies and almost all were protected. However, some blood cancer patients and other immunosuppressed patients don’t make the antibody to help fight the virus. While there still may be some protection through vaccination, people who don’t make antibodies may be at greater risk of ‘breakthrough’ infection, even after being fully vaccinated,” Nichols said.
The likelihood of having COVID-19 antibodies after vaccination varied by blood cancer type, according to the study findings.
Patients with non-Hodgkin lymphoma (NHL) were the least likely to have detectable antibodies, with seronegativity (meaning that no detectable amounts of the virus/antibodies were found) ranging by NHL subtype – from 21% of patients with diffuse large B-cell lymphoma being seronegative, compared to 56% of those with mantle cell lymphoma.
“There is no definitive way to know without testing, but patients who have B-cell malignancies, such as non-Hodgkin lymphoma and chronic lymphocytic leukemia appear to be at higher risk,” Nichols said. “Also … recent use of therapies which suppress the B-lymphocytes – anti-CD20 antibody therapies, Bruton tyrosine kinase (BTK) inhibitors and others – may put patients at higher risk.”
These drugs impair B-cells that make antibodies. Similarly, more than a third (36%) of patients with chronic lymphocytic leukemia (CLL) were seronegative, although 30% reported not having cancer treatment within the last two years. This points toward the potential of the actual disease inhibiting B cell functioning. Patients with CLL who were treated within the last few years had even higher rates of seronegativity.
CAR-T cell therapy may also affect vaccine response, as six out of seven patients with diffuse large B-cell lymphoma or follicular lymphoma were seronegative after being vaccinated. Again, this is likely due to the inhibition of normal B cells. Although, 80% of patients with myeloma who received a different type of CAR-T cell therapy produced antibodies.
Of all the blood cancer types, multiple myeloma had the lowest rate (5%) of seronegativity, meaning that patients with multiple myeloma were most likely to develop antibodies from the vaccine.
Despite these findings, Nichols encourages patients with blood cancer to get the COVID-19 vaccine, as the safety profile in the patients surveyed was similar to that in the rest of the population.
“Patients should definitely get vaccinated, unless their physician tells them they have a medical reason not to,” she said. “Antibodies may not be the only way the vaccine protects us from COVID-19.”
If patients suspect that they’ve been exposed to COVID-19, they should tell their health care team immediately. Nichols also advocated for patients to continue to social distance, wear masks and avoid crowded, poorly ventilated spaces, even after getting their vaccine.
“Get vaccinated, act unvaccinated,” she said.
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