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COVID-19: SARS-CoV-2 infection and vaccination assessed in patients with cancer
Patients with cancer who have been double-vaccinated against SARS-CoV-2 have diminished levels of neutralizing antibodies against some variants of concern, according to research published in Nature Cancer. The findings are part of a pair of papers that may have implications for the ongoing management of patients with cancer during the pandemic.
As many countries continue to ease COVID-19 restrictions, the spread of variants of concern, such as the highly infectious Delta variant, is fueling concerns over the durability and potency of the responses elicited by SARS-CoV-2 vaccines in key vulnerable groups, such as those with cancer. Although patients with cancer have been prioritized for vaccination, they were not included in pivotal vaccine studies, so comparatively little is known about their response to both infection and vaccination.
Samra Turajlic and colleagues present two papers from the CAPTURE project — a prospective, longitudinal cohort study in the UK investigating these issues. In the first paper 585 patients with cancer (median age of 60 years; 60% male) were evaluated after the administration of two doses of either the Oxford-AstraZeneca (AZD1222) vaccine or the Pfizer-BioNTech (BNT162b2) vaccine, administered 12 weeks apart. Patients with blood cancer in particular were found to have low levels of or no detectable neutralizing antibodies against each variant of concern studied (Alpha, Beta or Delta), even after their second vaccine dose. This suggests that these people may be particularly vulnerable to variants of concern, and raises the potential need for members of this group to self-shield. In addition, prior infection with SARS-CoV-2 boosted levels of vaccine-induced neutralizing antibodies in patients with cancer, which provides support for the idea that individuals with cancer, and especially those with blood cancer, may benefit from a third vaccine dose.
Furthermore, another type of immune response, known as a T cell response, was detected in 79% of vaccinated patients, which, was the same in patients with solid or blood cancers and for either vaccine. Importantly, vaccination induced this response in patients who did not have a neutralizing antibody response. Further work will be needed to fully understand how T cells contribute to protection.
In the second paper, which looked at responses to SARS-CoV-2 infection in 118 unvaccinated patients with cancer (median age of 59 years; 54% male), Turajlic and co-authors found that although patients with tumorous cancers developed durable neutralizing antibody responses to SARS-CoV-2, patients with blood cancer had impaired immune responses to the same infection. Further, T cell responses following infection were detected in most cancer patients, though more frequently in patients with solid cancer (up to 76%) versus those with blood cancers (52%). Taking these data together, the authors suggest that patients with blood cancer are more susceptible to reinfection and to the risk of severe disease.
The authors argue that their data support the prioritization of patients with cancer for booster vaccinations and that personal risk mitigation and ongoing public health measures remain relevant, especially when community transmission of variants of concern is high.
