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Blood cancer patients produce lower antibody response to Omicron despite third covid vaccine

Blood cancer patients given a third COVID-19 vaccination have been found to produce a limited antibody response to the Omicron variant

Patients who have blood cancer produce a limited neutralising antibody response to the Omicron variant even after their third covid vaccine dose, according to a study by a UK team of researchers.

Cancer patients who are infected with COVID-19 are known to have a higher mortality risk compared to those without the disease but the exclusion of cancer patients from the vaccine trials has meant that there was a level of uncertainty over the extent to which neutralising antibodies were produced in response to vaccination. Once data did become available, it was clear how those with blood cancers such as chronic lymphocytic leukaemia, mounted an impaired antibody response to vaccination. Moreover, with the emergence of covid-19 variants capable of immune escape, the antibody response among cancer patients could be even worse. In fact, such fears appear to have been realised with one study reporting that blood cancer patients were more likely to have undetectable neutralising antibodies compared to those with solid cancers against both the wild-type and the alpha, beta and delta COVID-19 variants of concern. Despite these findings, administration of a third COVID-19 vaccine appears to boost the neutralising antibody response for those with solid tumours but the response remains muted in blood cancer patients. For instance, one study found that following the third dose, only 54% had detectable neutralising antibodies against Delta and 54% against Beta.

For the present study, the researchers focused their attention on the Omicron variant and sought to examine the immune response generated in response to this variant in those with both solid tumours and blood cancers. The team used a live-virus micro-neutralisation assay to evaluate the response to Omicron following three doses of COVID-19 vaccines in participants enrolled in the CAPTURE study, which was a prospective and longitudinal study of patients with cancer.

Blood cancer patients’ response to third vaccine dose

The researchers enrolled 199 patients, 58% of whom had a solid cancer and the remainder a blood cancer, all of whom had received a third COVID-19 vaccine dose. They also included a matched sample before the third dose which included 179 patients (115 with solid cancers and 84 with a blood cancer).

After two COVID-19 vaccine doses among the 100 patients with solid cancers, 37% generated detectable neutralising antibodies against Omicron. In contrast, among 79 patients with a blood cancer, only 19% generated a detectable response to Omicron after two vaccine doses.

With a third vaccine dose, among the 115 patients with a solid cancer, neutralising antibodies to Omicron were detected in 90% of patients. However, for the 84 patients with a blood cancer, after a third vaccine dose, Omicron neutralising antibodies were only detectable in 56% of patients.

Based on these findings, the authors concluded that while a third vaccine dose enabled those with solid cancers to produce a robust neutralising antibody response to Omicron, only half of those with a blood cancer were able to mount a sufficient response, highlighting the need for a possible fourth dose in this patient cohort.

Fendler A et al. Omicron neutralising antibodies after third COVID-19 vaccine dose in patients with cancer Lancet 2022

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