The type of cancer treatment a patient is receiving impacts the efficacy of COVID-19 vaccines, according to a study published in the Journal of the National Cancer Institute.

Researchers found that patients who had recently received cytotoxic chemotherapy or an immune checkpoint inhibitor had a lower risk of severe COVID-19 if they were fully vaccinated.

However, patients who had received radiation and those who had a history of chimeric antigen receptor (CAR) T-cell therapy or hematopoietic stem cell transplant (HSCT) did not derive the same benefit from vaccination. In addition, the efficacy of vaccines among patients receiving targeted therapy varied according to cancer type.

Continue Reading

This trial ( Identifier: NCT04387656) included 1610 adults with cancer who were enrolled between May 21, 2020, and February 1, 2022. All patients had a positive SARS-CoV-2 test within 14 days of enrollment. 

All patients had recently undergone anticancer treatment or had a history of CAR T-cell therapy or HSCT. Patients who were 2 weeks past their second dose of a monovalent mRNA vaccine (Pfizer-BioNTech or Moderna) or a single dose of an adenovirus vector vaccine (Johnson & Johnson) at the time of their positive SARS-CoV-2 test were considered to be fully vaccinated.

Overall, patients who were fully vaccinated had a significantly lower risk of developing severe COVID-19, defined as hospitalization or death within 30 days, compared with patients who were unvaccinated or partially vaccinated (odds ratio [OR], 0.44; 95% CI, 0.28-0.72; P =.0008). 

However, outcomes varied according to the type of cancer a patient had and the type of treatment a patient received. 

The risk of severe COVID-19 was not significantly different between the fully vaccinated and unvaccinated groups among patients who had received:

  • HSCT or CAR T-cell therapy (OR, 1.00; 95% CI, 0.19-4.09) 
  • Targeted therapy for a solid tumor (OR, 0.47; 95% CI, 0.19-1.09)
  • Radiation therapy (OR, 0.31; 95% CI, 0.08-1.01).

On the other hand, the risk of severe COVID-19 was significantly lower among fully vaccinated patients who had received:

  • Cytotoxic chemotherapy (OR, 0.41; 95% CI, 0.23-0.73)
  • Immune checkpoint inhibitor therapy (OR, 0.27; 95% CI, 0.11-0.64)
  • Targeted therapy for a hematologic malignancy (OR, 0.36; 95% CI, 0.17-0.75).

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Best AF, Bowman M, Li J, et al. COVID-19 severity by vaccination status in the NCI COVID-19 and Cancer Patients Study (NCCAPS). J Natl Cancer Inst. Published online January 25, 2023. doi:10.1093/jnci/djad015