Vaccine Effectiveness Against COVID-19 Breakthrough Infection in Patients With Cancer

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In a population-based study based on data from the UK Coronavirus Cancer Evaluation Project (UKCCEP) reported in The Lancet Oncology, Lennard Y.W. Lee, DPhil, and colleagues found that COVID-19 vaccination was effective in preventing breakthrough infection among patients with cancer but less effective than in individuals without cancer.

Lennard Y.W. Lee, DPhil

Lennard Y.W. Lee, DPhil

Study Details

The case-control study used data from the UKCCEP registry to identify a case cohort of patients with cancer and a control cohort of individuals without cancer who had received two doses of vaccine and had documented SARS–CoV-2 polymerase chain reaction (PCR) test results during the period from December 2020 to October 2021.

The coprimary endpoints were overall vaccine effectiveness against breakthrough infections after the second dose (positive PCR COVID-19 test), and vaccine effectiveness against breakthrough infections 3 to 6 months after the second dose.  

Key Findings

Breakthrough infections occurred in 42,882 of 377,194 patients with cancer and in 5,748,708 of 28,010,955 persons in the control cohort.

Overall vaccine effectiveness was 65.5% (95% confidence interval [CI] = 65.1%–65.9%) in the cancer cohort vs 69.8% (95% CI = 69.8%–69.9%) in the control cohort. Vaccine effectiveness at 3 to 6 months after the second vaccine dose was 47.0% (95% CI = 46.3%–47.6%) vs 61.4% (95% CI = 61.4%–61.5%).

Analysis in the cancer cohort showed:

  • Higher effectiveness with two doses of the BNT162b2 (Pfizer-BioNtech) vaccine vs the ChAdOx1 nCoV-19 (AstraZeneca) vaccine
  • Lower effectiveness among patients with hematologic malignancies (particularly lymphoma or leukemia) vs solid malignancies
  • Higher effectiveness in patients with myeloma among those with a hematologic malignancy
  • Lower effectiveness among patients with head and neck malignancies vs other solid tumors
  • Lower effectiveness among patients who had vs had not received systemic anticancer therapy or radiotherapy
  • Lower effectiveness among those who had received systemic anticancer therapy or radiotherapy at ≤ vs > 12 months from data cutoff.

The investigators concluded, “COVID-19 vaccination is effective for individuals with cancer, conferring varying levels of protection against breakthrough infections. However, vaccine effectiveness is lower in patients with cancer than in the general population. COVID-19 vaccination for patients with cancer should be used in conjunction with nonpharmacological strategies and community-based antiviral treatment programs to reduce the risk that COVID-19 poses to patients with cancer.”

Dr. Lee, of the Department of Oncology, University of Oxford, is the corresponding author for The Lancet Oncology article.

Disclosure: The study was funded by the University of Oxford, University of Southampton, University of Birmingham, Department of Health and Social Care, and Blood Cancer UK. For full disclosures of the study authors, visit


The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.