New Study Deciphers the Value of COVID-19 Boosters in Patients With Cancer

Study author Jacek Skarbinski, MD

A new study finds that both COVID-19 monovalent and bivalent boosters showed a reduction in COVID-19 hospitalizations in people with cancer who received chemotherapy or immunotherapy within the previous year. The study’s findings were published last week in JAMA Oncology.¹

"In a retrospective cohort study among persons with cancer in the US, additional monovalent COVID-19 vaccines reduced COVID-19 hospitalizations by 29%, with a number needed to vaccinate of 166 in January to August 2022, and a bivalent COVID-19 vaccine reduced COVID-19 hospitalizations by 30%, with a number needed to vaccinate of 451 in September 2022 to August 2023," the investigators wrote.

The study’s first author, Jacek Skarbinski, MD, a research scientist at the Kaiser Permanente Division of Research and practicing infectious diseases physician with the Permanente Medical Group, spoke with Contagion, who offered some insights on the study’s significant findings. 

Contagion: What do the findings of this study suggest about the real-world effectiveness of COVID-19 monovalent and bivalent boosters in reducing hospitalizations and ICU admissions among cancer patients?

Skarbinski: These findings clearly demonstrate that COVID-19 vaccines offer substantial protection among cancer patients and can prevent severe COVID-19 requiring hospitalization in cancer patients.

Contagion: The number needed to vaccinate (NNV) to prevent one COVID-19 hospitalization varied between the monovalent and bivalent booster periods. How should clinicians interpret this in terms of public health impact and vaccine prioritization for cancer patients?

Skarbinski: The number needed to vaccinate in both time periods was very low among cancer patients (<500) compared with non-immunocompromised persons (>1100). We would need to vaccinate substantially fewer cancer patients to prevent one COVID-19 hospitalization and thus cancer patients should be prioritized for COVID-19 vaccination.

Learn more: In People With Cancer, COVID-19 Vaccine Boosters Reduce Hospitalizations

Contagion: Despite evidence of vaccine effectiveness, booster uptake among cancer patients remained low. What factors might be contributing to this, and what strategies could improve vaccine coverage in this high-risk population?

Skarbinski: Vaccine uptake was low among cancer patients, but was even lower among non-immunocompromised persons (eg, vaccine uptake September 1, 2022 to August 31, 2023 was 38% among cancer patients and 24% among non-immunocompromised patients). Routine and seasonal vaccination is generally not integrated into cancer care, but most patients undergoing cancer care mostly engage with their cancer treatment team, and thus might not prioritize vaccination. Integrating vaccinations into cancer care and prioritizing vaccination as part of routine cancer care might increase uptake.

Contagion: Given the statistically significant protection observed in this study, how might these findings influence ongoing guidance or policy for COVID-19 vaccination in immunocompromised populations, especially those with cancer?

Skarbinski: This study supports the current guidelines recommending 2 doses of COVID-19 vaccination 6 months apart during the September 1 to August 31 season. Patients with cancer should be encouraged to get both doses of vaccine and health systems should develop strategies to increase vaccine uptake.

Reference
1.Skarbinski J, Elkin EP, Ziemba YC, et al. COVID-19 Vaccine Booster Uptake and Effectiveness Among US Adults With Cancer. JAMA Oncol. Published online July 17, 2025. doi:10.1001/jamaoncol.2025.2020