Covid-19: Vaccine effectiveness wanes more rapidly for cancer patients, study finds

Covid-19 vaccination is effective for cancer patients but protection wanes much more rapidly than in the general population, a large study has found.1

Vaccine effectiveness is much lower in people with leukaemia or lymphoma, those with a recent cancer diagnosis, and those who have had radiotherapy or systemic anti-cancer treatments within the past year, according to the research published in Lancet Oncology.

The authors of the world’s largest real world health system evaluation of covid-19 in cancer patients highlighted the importance of booster programmes, non-pharmacological strategies, and access to antiviral treatment programmes in order to reduce the risk that covid-19 poses to cancer patients.

The study, jointly led by the universities of Birmingham, Oxford, and Southampton and the UK Health Security Agency, included 377 194 people with active or recent cancer who had received two doses of a covid-19 vaccine, of whom 43 882 had breakthrough SARS-CoV-2 infections. The control population consisted of 28 010 955 people of whom 5 748 708 had a breakthrough infection.

Overall vaccine effectiveness following the second vaccine dose was found to be 69.8% in the control population and slightly lower in the cancer population at 65.5%. However, at 3-6 months following the second vaccine dose, effectiveness had reduced to 47% in the cancer cohort compared with 61.4% in the control population.

Vaccination was found to offer higher protection against covid-19 associated hospital admission (83.3%) and death (93.4%) than against breakthrough infections in the cancer cohort, but this protection also waned by 3-6 months after the second dose.

Vaccine effectiveness, both overall and at 3-6 months, was lower among patients with haematological malignancies than among those with solid organ malignancies. At 3-6 months vaccine effectiveness was 12.8% for patients with lymphoma and 18.5% for leukaemia. By contrast vaccine effectiveness in the myeloma subgroup was high—63.9% at 3-6 months. Among solid cancers, vaccine effectiveness was lowest in those with head and neck malignancies.

The study did not tackle the mechanisms for the drop in vaccine effectiveness but the authors said patients, especially those with lymphoma and leukaemia, might have a limited capacity to maintain immunological vaccine memory as a consequence of cancer treatments that suppress immune responses.

Peter Johnson, professor of medical oncology at the University of Southampton and joint author of the study, said, “This study shows that for some people with cancer, covid-19 vaccination may give less effective and shorter lasting protection. This highlights the importance of vaccination booster programmes and rapid access to covid-19 treatments for people undergoing cancer treatments.”

Study leader, Lennard Lee, department of oncology, University of Oxford, said, “Cancer patients should be aware that at 3-6months they are likely to have less protection from their coronavirus vaccine than people without cancer. It is important that people with a diagnosis of cancer are up to date with their coronavirus vaccination and have had their spring booster if they are eligible.”

Helen Rowntree, director of research, services, and engagement at Blood Cancer UK, said, “This study shows that immunity wanes faster in people with blood cancer, who are entitled to five vaccine doses. We’d encourage everyone with blood cancer to make sure they are getting these doses.”