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Researchers say people with certain types of cancer can have low antibody response levels after getting a COVID-19 vaccination. Phynart Studio/Getty Images
  • Two new studies are raising concerns about the immune response people with cancer are receiving from COVID-19 vaccinations.
  • One study noted that a significant number of people with blood cancers show low levels of virus-fighting antibodies after vaccination.
  • Another study reported low response levels after an initial vaccination dose for people with solid tumor cancers but a much higher response after a second dose.

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Since the COVID-19 pandemic began 16 months ago, there have been few comprehensive studies on how the mRNA vaccines (Moderna/Pfizer-BioNtech) affect people who have cancer and are undergoing treatment.

However, two recent studies — one involving blood cancers and one involving solid tumor cancers — shed new light and bring new concerns.

A study released last week from the Leukemia and Lymphoma Society (LLS) shows that while the vaccines are safe, about 1 in 4 people with blood cancer fail to produce detectable antibodies after vaccination.

The research, “Antibody response to SARS-CoV-2 vaccines in patients with hematologic malignancies,” published in the journal Cancer Cell is the largest such study to date.

Researchers examined more than 1,400 people across all major blood cancers, including non-Hodgkin’s lymphoma, Hodgkin’s lymphoma, leukemia, and multiple myeloma.

Dr. Gwen Nichols, chief medical officer of LLS, told Healthline that people with non-Hodgkin’s lymphoma were less likely to have detectable antibodies from the vaccine among all the blood cancers.

The percentage of people with non-Hodgkin’s lymphoma who were seronegative following vaccination ranged from 21 percent to as high as 56 percent, she said.

Among people with leukemia, those with chronic lymphocytic leukemia were most likely to be seronegative, a test result showing a low level of antibody response.

People with multiple myeloma had higher rates of detectable antibodies than other blood cancers.

Only 5 percent of people with multiple myeloma were seronegative.

However, the researchers noted that other studies have reported higher seronegative rates (up to 15 percent) in people with multiple myeloma.

Bottom line?

“There are 250,000 patients who are not making antibodies in the blood cancer population in the United States alone,” Nichols said.

But Nichols added that she and her colleagues do not want anyone to use the results as a reason not to get vaccinated.

“The No. 1 takeaway from this study should be that 75 percent of blood cancer patients do respond to the vaccine and that the vaccines are safe,” she said.

Nichols added that people with blood cancer need to understand that they are “at higher risk because they are immunosuppressed, potentially from both the cancer and the treatment.”

She encourages every person with blood cancer to get vaccinated.

“Young people can get COVID and not get sick. But if they get the virus and have a parent or grandparent, and they come in contact with them, they could kill them,” she said. “It’s not a joke. We encourage all blood cancer patients to please think about getting vaccinated for your loved ones.”

Meanwhile, another new study from Israel cancer researchers published in JAMA Oncology shows that people with solid tumor cancer in active treatment had a “pronounced lag” in antibody production after receiving the first Pfizer-BioNTech COVID-19 vaccine.

But the rate increased substantially after receiving the second dose, said Dr. Irit Ben-Aharon, director of the oncology division at Rambam Health Care Campus in northern Israel.

The study evaluated the serologic status and safety of the vaccine in 232 people receiving active treatment for solid tumor cancers and 261 healthcare workers who served as control subjects.

After the first dose of the vaccine, 29 percent of the people with cancer were seropositive, compared with 84 percent of the controls.

After the second dose, the seropositive rate of the people with cancer reached 86 percent and reported adverse events that resembled those of healthy individuals.

The vaccine appears to be safe with satisfactory levels of seropositivity in people undergoing treatment for cancer, she explained, but protection may occur later compared with the rest of the population.

“These are patients who are being treated with chemotherapy, immunotherapy, biological therapy, etc. Systemic treatment probably affects their immune response,” Ben-Aharon said.

She added that the study’s findings illustrate the importance of following through with the second vaccination.

“The manufacture of the antibodies may take more time,” Ben-Aharon said. “The lag is troubling, but most solid tumor patients do develop antibodies.”