COVID-19 vaccination is safe and efficacious for cancer patients receiving immune checkpoint inhibitors (ICIs) and should not interrupt therapy, according to researchers.

The researchers observed a low rate of new immune-related adverse events (irAEs) among patients who were vaccinated within 90 days of ICI treatment. In addition, there was no excess risk of COVID-19 in this patient group, the researchers reported.

The team reported these results in the Journal of the National Comprehensive Cancer Network.

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The researchers conducted an electronic pharmacy record analysis of patients with cancer who received a COVID-19 mRNA vaccine between January 16, 2021, and March 27, 2021. Patients also received ICI therapy within 90 days before or after their first vaccine dose.

A total of 408 patients (median age, 71 years; 53% men) were included in the study. Patients were receiving treatment for thoracic cancer (30%), genitourinary cancer (21%), upper gastrointestinal cancer (12%), melanoma (12%), gynecologic cancer (10%), sarcoma (5%), head and neck cancer (5%), lower gastrointestinal cancer (3%), glioblastoma (1%), lymphoma (1%), and breast cancer (1%).

The ICIs patients received included pembrolizumab only (65%), nivolumab only (24%), combination ipilimumab plus nivolumab (10%), ipilimumab only (0.7%), or all 3 agents (0.3%). Most patients (95%) received the Pfizer-BioNTech COVID-19 vaccine.

The researchers followed patients for 90 days after the first vaccine dose. During that time, 27 patients (7%) experienced a new irAE — 21 with grade 1 events, 2 with grade 2 events, and 4 with grade 3 events.

Grade 1 events included dermatitis (n=10), arthralgias (n=3), diarrhea (n=2), pneumonitis (n=2), transaminitis (n=2), thyroiditis (n=1), and arthritis and rash (n=1). The grade 2 events were pneumonitis (n=1) and arthritis and rash (n=1). The grade 3 events were diarrhea (n=3) and colitis (n=1).

Among 54 patients with previous irAEs from ICIs, 3 (6%) experienced a recurrent irAE after vaccination. Among 52 patients who started a new immunotherapy agent after vaccination, 9 (17%) had an irAE.

Two patients were diagnosed with COVID-19 after vaccination. Eleven patients had been diagnosed with COVID-19 before vaccination.

“Our data do not show a higher risk of immune toxicity among ICI-treated patients who received the COVID-19 vaccine, including those newly started on therapy. The findings should encourage new and third-dose vaccine uptake among patients with cancer receiving ICI treatment, without interruption of cancer therapy,” the researchers concluded.

Limitations of this study include the absence of a temporally aligned comparison group of patients receiving ICI therapy who did not undergo COVID-19 vaccination, and a sample size not large enough to capture the risk of post-vaccine rare events.

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


Widman AJ, Cohen B, Park V, McClure T, Wolchok J, Kamboj M. Immune-related adverse events among COVID-19-vaccinated patients with cancer receiving immune checkpoint blockade. J Natl Compr Canc Netw. 2022;20(10):1134-1138. doi:10.6004/jnccn.2022.7048