A new paper from the UK Coronavirus Cancer Project has shown that antibody testing is a valuable tool for identifying cancer patients most at risk of breakthrough COVID-19 infection.
There is an ongoing need for tools to predict who is most at risk from COVID-19 breakthrough infection, in order to target resources and interventions to the most vulnerable populations.
In this ‘hyper-accelerated’ study, the researchers set out to assess the usefulness of COVID-19 antibody testing to predict vulnerability of high-risk groups, such as people with cancer.
Their aim was to ascertain whether breakthrough infections in people with cancer were associated with vaccine antibody levels.
They analysed 4,249 antibody test results from people with cancer who had been vaccinated against COVID-19, and compared these with 294,230 from the general population. The analysis was done from September 2021 to March 2022, a period covering the expansion of the UK’s booster programme. Patients could sign up to take part in any cancer centre in the UK.
The results, published in the journal JAMA Oncology, showed that, among people with cancer, an absence of antibodies was associated with a substantially higher risk (3 times greater) of breakthrough infection and (6 times greater) of hospitalisation, compared to people where antibodies were detected.
People with cancer were 47 times less likely to have detectable levels of antibodies than people in the general population. People with leukaemia or lymphoma had the lowest antibody levels (19.2% had no detectable vaccine antibody response, compared to 4.2% of people with other types of cancer and 0.1% of people in the general population). People with stage 4 cancer, or who were receiving certain types of therapy (chemotherapy, hormone therapy, targeted therapy or immune therapy) also had lower levels of antibodies.
The researchers concluded that antibody testing provides a good indication of infection risk among people with cancer, and could be used to target transmission prevention measures to those cancer patients that need it most, as well as to inform decisions about additional vaccine doses, prophylactics, and early treatment should a person become infected. They hope that their findings will lead to further studies, ultimately helping to minimise impact on cancer treatment and maximise quality of life.
The UK Coronavirus Cancer Project links 86 cancer centres and 250 clinicians. It is the longest-running pandemic response programme in the UK.