The first study to evaluate the clinical characteristics and outcomes of fully vaccinated patients with cancer who had breakthrough COVID-19 infections indicates they remained at high risk for hospitalization and death, according to a news release from Vanderbilt University Medical Center.
The study, published in Annals of Oncology, showed that fully vaccinated patients who experienced breakthrough infections had a hospitalization rate of 65%, an ICU or mechanical ventilation rate of 19%, and a 13% death rate. The study was conducted by the COVID-19 and Cancer Consortium (CCC19), a group of 129 research centers that has been tracking the impact of COVID-19 on patients with cancer since the beginning of the pandemic.
“Patients with cancer who develop breakthrough COVID-19 even following full vaccination can still experience severe outcomes, including death,” said Toni Choueiri, MD, Director of the Lank Center for Genitourinary Care at Dana-Farber Cancer Institute and a senior author on the report. “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.”
Patients were considered fully vaccinated after having received two doses of either the Pfizer-BioNTech vaccine or the Moderna vaccine, or one dose of the vaccine from Johnson & Johnson, with the last vaccine dose long enough before breakthrough COVID-19, to consider them as fully vaccinated. The data were collected between Nov. 1, 2020, and May 31, 2021, before booster vaccines were recommended for patients with cancer by the U.S. 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 has 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,” said Jeremy Warner, MD, Director of the CCC19 Research Coordinating Center, Associate Professor at Vanderbilt-Ingram Cancer Center and a senior author of the study.
The consortium identified 1,787 patients with cancer and COVID-19 for the study, the vast majority of which were unvaccinated. The number of fully vaccinated patients was 54, and 46% of those fully vaccinated had reduced levels of lymphocytes — the T cells and B cells responsible for immunological responses to viruses.
Lymphopenia commonly occurs in patients with cancer receiving anti-CD20 monoclonal antibodies or CAR-T-cell treatments for hematologic malignancies, including lymphoma and leukemia. The study appears to support previous observations that patients with hematologic malignancies are at greater risk for severe outcomes from COVID-19. However, 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, the researchers noted. Patients on a treatment regimen of corticosteroids also appeared to be more susceptible to hospitalization.