Link between COVID-19 vaccination and breakthrough infections, complications in cancer patients

Patients with cancer are known to have increased risk of COVID-19 complications, including death.In a recent study, published in JAMA Oncology, the researchers have found that patients with cancer had greater risk of SARS-CoV-2 infection and worse outcomes than patients without cancer, and the risk was highest for patients with hematologic cancer and any patients with cancer receiving active treatment. It was also found that triple vaccination was associated with lower risk of poor outcomes.

Reports have shown reduced seroresponse following vaccination in patients with cancer. As such, in this study the team hypothesized that patients with cancer have worse outcome after vaccination, with greater breakthrough infections and worse COVID-19 outcomes, particularly for patients with hematologic cancer.

In this large population-based cohort study, they set out to examine the relative risk of SARS-CoV-2 breakthrough infections and COVID-19 outcomes in vaccinated patients with cancer vs matched noncancer controls, and separately, in those with hematologic vs solid cancer.

They included linked administrative databases in Ontario, Canada, in residents 18 years and older who received COVID-19 vaccination. Three matched groups were identified: 1:4 match for patients with hematologic and solid cancer to noncancer controls (hematologic and solid cancers separately analyzed), 1:1 match between patients with hematologic and patients with solid cancer.

They found that COVID-19 severe outcomes were significantly higher in patients with cancer compared to patients without cancer. Risk of severe outcomes was higher among patients with hematologic cancer than patients with solid cancer. Patients receiving active treatment had a further heightened risk for COVID-19 severe outcomes, particularly those who received anti-CD20 therapy. Third vaccination dose was associated with lower infection and COVID-19 complications, except for patients receiving anti-CD20 therapy.

Reference:

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