Patients with cancer have a higher risk of breakthrough SARS-CoV-2 infection and worse COVID-19 outcomes than patients without cancer, according to a study published in JAMA Oncology.

The risk of breakthrough infection and poor outcomes was highest for cancer patients receiving active treatment and those with hematologic malignancies. Poor outcomes were generally less likely for patients who were triple vaccinated.

For this study, researchers evaluated data from 289,400 patients with cancer and 1,157,600 matched control individuals without cancer. All patients were residents of Ontario, Canada, and all had received at least 2 doses of a COVID-19 vaccine.

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Among patients with cancer, 39,880 had hematologic malignancies, and the remaining 249,520 had solid tumors. Overall, 13.2% of the cancer patients were receiving chemotherapy and 0.8% were receiving anti-CD20 therapy.

Breakthrough SARS-CoV-2 infections were significantly more likely among cancer patients than among the control individuals (adjusted hazard ratio [aHR], 1.05; 95% CI, 1.01-1.09; P =.02).

The risk of breakthrough infection was similar between patients with solid tumors and control individuals (aHR, 1.00; 95% CI, 0.96-1.05; P =.87), but the risk was significantly higher among patients with hematologic malignancies (aHR, 1.33; 95% CI, 1.20-1.46; P <.001). 

Patients with hematologic malignancies had an even higher risk of breakthrough infection if they were receiving chemotherapy (aHR, 1.63; 95% CI, 1.34-1.98; P <.001) or anti-CD20 therapy (aHR, 1.88; 95% CI, 1.27-2.78; P =.002). 

Compared with control individuals, the patients with cancer had worse COVID-19 outcomes, including death, hospitalization or death, and emergency department (ED) visits. This was true for patients with solid tumors and those with hematologic malignancies. The cancer patients had an even higher risk of poor outcomes if they were receiving chemotherapy or anti-CD20 therapy. 

ED VisitHospitalization or DeathDeath
Cancer patients vs controlsaHR, 1.28 (95% CI, 1.17-1.39; P <.001)aHR, 1.52 (95% CI, 1.42-1.63; P <.001)aHR, 1.60 (95% CI, 1.42-1.81; P <.001)
Solid tumor patients vs controlsaHR, 1.06 (95% CI, 0.96-1.17; P =.29)aHR, 1.29 (95% CI, 1.20-1.39; P <.001)aHR, 1.43 (95% CI, 1.24-1.64; P <.001)
Hematologic cancer patients vs controlsaHR, 2.54 (95% CI, 2.12-3.05; P <.001)aHR, 2.51 (95% CI, 2.21-2.85; P <.001)aHR, 2.32 (95% CI, 1.81-2.97; P <.001)
Hematologic cancer patients on chemotherapy vs controlsaHR, 4.22 (95% CI, 3.08-5.76; P <.001)aHR, 3.97 (95% CI, 3.20-4.92; P <.001)aHR, 3.21 (95% CI, 2.19-4.71; P <.001)
Solid tumor patients on chemotherapy vs controlsaHR, 1.59 (95% CI, 1.25-2.03; P <.001)aHR, 2.64 (95% CI, 2.19-3.18; P <.001)aHR, 4.48 (95% CI, 3.32-6.86; P <.001)
Hematologic cancer patients on anti-CD20 therapy vs controlsaHR, 12.31 (95% CI, 6.37-23.79; P <.001)aHR, 7.14 (95% CI, 4.67-10.92; P <.001)aHR, 6.28 (95% CI, 2.86-13.82; P <.001)

Receipt of a third vaccine dose reduced the risk of ED visits, death, and hospitalization or death across groups, except in patients with hematologic cancers who were receiving anti-CD20 therapy.

“Our findings support the prioritization of high-risk populations for booster vaccination, forthcoming variant-specific vaccine products, preexposure prophylaxis (where available), and rapid antiviral treatment in the face of SARS-CoV-2 infection as COVID-19 continues to be relevant with ongoing surges leading to excess morbidity and mortality,” the researchers concluded.

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


Gong IY, Vijenthira A, Powis M, et al. Association of COVID-19 vaccination with breakthrough infections and complications in patients with cancer. JAMA Oncol. Published online December 29, 2022. doi:10.1001/jamaoncol.2022.6815

This article originally appeared on Cancer Therapy Advisor