Cancer Patients Have Severe COVID-19 Outcomes Despite Vaccination

Cancer patients who are fully vaccinated shouldn’t assume they will be protected against severe COVID-19 if they get a breakthrough infection. That’s according to a new study from a consortium of cancer centers. Find out why that appears to be the case and what can be done to protect those patients.

BOSTON—Vaccination alone might not be enough to protect cancer patients from severe COVID-19.

An article published in Annals of Oncology warns that patients with cancer who develop breakthrough COVID-19 following full vaccination still remain susceptible to severe outcomes. In fact, the article states, “Hematologic malignancies are over-represented among vaccinated patients with cancer who develop breakthrough COVID-19.”

Researchers from the COVID-19 and Cancer Consortium (CCC19), a group of 129 research centers which has been tracking the impact of COVID-19 on cancer patients since the beginning of the pandemic, urge that “vaccination of close contacts, masking, boosters, and social distancing are needed to protect patients with cancer.”

“Vaccination is an important preventive health measure to protect against symptomatic and severe COVID-19,” according to the report. “Impaired immunity secondary to an underlying malignancy or recent receipt of anti-neoplastic systemic therapies can result in less robust antibody titers following vaccination and possible risk of breakthrough infection. As clinical trials evaluating COVID-19 vaccines largely excluded patients with a history of cancer and those on active immunosuppression (including chemotherapy), limited evidence is available to inform the clinical efficacy of COVID-19 vaccination across the spectrum of patients with cancer.”

The study found that cancer patients “who develop COVID-19 following vaccination have substantial comorbidities and can present with severe and even lethal infection.”

The study was the first to evaluate the clinical characteristics and outcomes of fully vaccinated cancer patients who had breakthrough COVID-19 infections indicates they remained at high risk for hospitalization and death. Those patients had a hospitalization rate of 65%, an ICU or mechanical ventilation rate of 19%, and a 13% mortality rate.

"Patients with cancer who develop breakthrough COVID-19 even following full vaccination can still experience severe outcomes, including death," explained senior author Toni Choueiri, MD, director of the Lank Center for Genitourinary Care at Dana-Farber Cancer Institute. "That is why a multilayered approach that includes masking and social-distancing, along with vaccination plus booster against COVID-19 remains an essential approach for the foreseeable future."

For purposes of the study, patients were considered fully vaccinated after having received two doses of either the BioNTech, Pfizer vaccine or the Moderna, NIAD vaccine, or one dose of the J&J vaccine, with the last vaccine dose long enough before breakthrough COVID-19, to consider them as fully vaccinated. The authors advise that their data were collected between Nov. 1, 2020, and May 31, 2021, before booster vaccines were recommended for patients with cancer by the national Centers for Disease Control and Prevention.

"Because measures of immunity are not routinely collected in clinical care, we don't know whether these were patients who mounted effective immune responses after vaccination; a lot of emerging data have suggested that patients with cancer, especially blood cancers, don't mount adequate protective antibody responses. It's important to note that many of the same factors that we identified prior to the availability of vaccination -- age, comorbidities, performance status, and progressing cancer -- still seem to drive many of the bad outcomes," pointed out senior author Jeremy Warner, MD, director of the CCC19 Research Coordinating Center, associate professor at Vanderbilt-Ingram Cancer Center.

As part of the study, the consortium identified 1,787 patients with cancer and COVID-19 for the study, with nearly all of them unvaccinated. Of the 65 patients who had been fully vaccinated, 46% had reduced levels of lymphocytes -- the T cells and B cells responsible for immunological responses to viruses.

Background information in the article noted that lymphopenia commonly occurs with cancer patients treated with anti-CD20 monoclonal antibodies or CAR-T-cell treatments for hematologic malignancies, including lymphoma and leukemia. The authors cautioned that the number of patients in the study is too small to make definitive conclusions about specific types of anticancer therapies that might be associated with breakthrough infections. They add that patients receiving corticosteroids also appeared to be more susceptible to hospitalization.

"Similar results (high mortality rates among fully vaccinated individuals) have been reported in other immunocompromised patient populations, such as organ transplant recipients, prior to the utilization of additional vaccine doses,” said senior author Dimitrios Farmakiotis, MD, an infectious disease clinician at the Warren Alpert Medical School of Brown University. “These findings come at a time of concerns that immune escape mutants such as the omicron strain may emerge from chronically infected patients with weakened immune systems. Thus, the immunosuppressed and their close contacts should be target groups for therapeutic and preventive interventions, including community-level outreach and educational efforts.”

Researchers conclude by calling for “a multilayered public health mitigation approach that includes vaccination of close contacts, boosters, social distancing, and mask-wearing should be continued for the foreseeable future.

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