Safety of COVID-19 vaccines in subjects with solid tumor cancers receiving immune checkpoint inhibitors.

The incidence of severe immune-related adverse events (irAEs) in cancer subjects receiving immune checkpoint inhibitors (ICIs) following COVID-19 vaccination and the relationship between the incidence of severe irAE and the interval between COVID-19 vaccination and ICI dose have not been established. We performed a retrospective study evaluating the incidence of irAEs in solid tumor subjects receiving ICI therapy who received any COVID-19 vaccinations since FDA authorization. irAEs were defined as severe with one or more grade 3 or above events (CTCAE v5.0), multiple organ involvement, or requiring hospitalization for management. Two hundred and eighty-four subjects who received COVID vaccinations from December 2020 and February 2022 were included in this analysis [median age at vaccination 67 years (IQR 59.0-75.0); 67.3% male]. Twenty-nine subjects (10.2%) developed severe irAEs, of which 12 subjects (41.4%) received ICI monotherapy, 10 subjects (34.5%) received combination ICI therapy with nivolumab and ipilimumab, and 7 subjects (24.1%) received ICI plus VEGFR-TKI therapy. Hospitalization occurred in 62% of subjects with severe irAEs, with a median duration of 3 days (IQR: 3.0-7.5 days). Immunosuppressive therapy was required in 79.3%, with a median duration of 103 days (IQR: 42.0-179.0). ICI therapy was discontinued in 51.7% of subjects with severe irAE; dosing was held or interrupted in 34.5%. Among severe irAEs, the median interval between vaccination and ICI treatment closest to the occurrence of severe irAE was 15.5 days (IQR: 10.0-23.0). In solid tumor cancer subjects receiving ICIs, COVID-19 vaccination is not associated with an increased incidence of severe irAEs compared to historical data and may be safely administered during ICI cancer therapy in subjects who lack contraindications.

A Rare Case Presentation of Vitiligo Associated With Atezolizumab.

Immune checkpoint inhibitors (ICIs) are monoclonal antibodies used in the treatment of solid and hematologic malignancies. Immune checkpoint inhibitors target the T-cell deactivation system via the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) receptor, programmed cell death protein 1 (PD-1) receptor, and programmed cell death ligand 1 (PD-L1). As a result, the activated T-cell enhances the host tumor response. However, even with their essential clinical benefits, ICIs are associated with a broad spectrum of adverse effects that can be generalized or tissue-specific inflammatory responses known as immune-related adverse events (irAEs). The most common dermatologic toxicity manifests mainly as maculopapular rash and pruritus. Understanding the complexity of immune-mediated response and the importance of clinical histopathologic correlation in recognizing irAEs allows for appropriate intervention and patient care due. We present the case of a 71-year-old African American male diagnosed with a large-cell poorly differentiated neuroendocrine tumor in the gastroesophageal junction of the stomach with mediastinal lymphadenopathy. He was treated with carboplatin, etoposide, and atezolizumab for 4 cycles. However, he developed vitiligo while on maintenance atezolizumab, which is rarely seen with atezolizumab use. Despite the improving clinical outcomes in oncology with ICIs, their adverse effects should not be ignored. When promptly recognized and treated, patients on ICI monotherapy may not need treatment interruption or discontinuation.

Impact of extended interval dosing of immune checkpoint inhibitors in lung cancer patients during the COVID-19 pandemic.

BACKGROUND: The COVID 19-pandemic has led physicians to change their approach to treating non-small cell lung cancer (NSCLC) to reduce hospital stays for patients. OBJECTIVES: We aimed to assess the toxicity and efficacy of extended interval (EI) dosing of immune checkpoint inhibitors (ICIs) compared to standard dosing (SD). METHODS: In this retrospective two-center study, we included patients with stage III/IV NSCLC who were treated with ICIs with or without maintenance pemetrexed during the month before March 2020. Adverse events and efficacy were collected until June 2021. Toxicity and survival were assessed using multivariate Cox models. RESULTS: Among the 134 patients identified (8 stage III and 126 stage IV; 66 first line and 60 second or subsequent lines), 70.9% received EI dosing. In the EI group, 12.6% of patients developed grade 3 or 4 immune-related adverse events versus 15.4% in the SD group (P- value = 0.8). Treatment was definitively discontinued due to toxicity in 9 patients in the EI group and in 5 in the SD group (P-value =0.5). Overall survival was not associated with dosage regimen or toxicity analyzed as a time-dependent variable. CONCLUSIONS: Our study suggests that EI dosing of ICIs did not affect toxicity and overall survival in lung cancer patients.

Recurrent and atypical immune checkpoint inhibitor-induced pneumonitis.

INTRODUCTION: Pembrolizumab (Keytruda) is a monoclonal antibody against the programmed cell death-1 (PD-1) receptor on lymphocytes, which is one of the immune checkpoint inhibitors (ICIs) approved for multiple solid and hematologic malignancies. Although ICIs have proven to be more effective and less toxic compared to chemotherapy, there are reports of adverse side effects with ICIs. For example, pneumonitis is a potentially lethal side effect occurring in 1%-5% of patients who received ICIs in clinical trials, and there are case reports with clinical and radiological features of checkpoint inhibitor-pneumonitis (CIP). CASE REPORT: We report an unusual case of pneumonitis with atypical imaging in a patient who received pembrolizumab for metastatic p16-positive squamous cell carcinoma of the base of the tongue. We discuss the approach to the recognition and management of atypical CIP in patients on pembrolizumab with the intent to standardize workup and increase awareness among healthcare providers in the new era of immunotherapy. MANAGEMENT AND OUTCOME: Serologic workup including laboratory studies for complete blood count (CBC), lactate, procalcitonin, SARS-CoV-2 (COVID-19), Legionella, Cytomegalovirus (CMV), Coccidioides, Coxiella, and viral respiratory panel were negative for infectious processes. Since CIP was suspected, the patient was started on steroid therapy. Interval computed tomography (CT) of the chest without contrast showed a resolution of pneumonitis. DISCUSSION: In this case report, we discuss our workup of CIP and initial testing to rule out other possible causes of the patient's symptoms and radiographic findings, and management of the patient's diagnosis of atypical CIP which led to complete clinical recovery from CIP.

COVID-19 vaccination in patients with cancer receiving immune checkpoint inhibitors: a systematic review and meta-analysis.

BACKGROUND: Immune checkpoint inhibitors (ICI) can cause off-target inflammatory and immune-related adverse events (irAE). Conceivably, COVID-19 vaccination could trigger an inflammatory and immune response that could induce or aggravate irAE. METHODS: The objective of this systematic review is to appraise the efficacy and safety of COVID-19 vaccination in patients with cancer treated with ICI. The literature search was performed in PubMed and Embase in English from December 2019 to February 2022. The review included clinical trials, observational cohort studies, case series, and case reports reporting on the clinical efficacy and safety of COVID-19 vaccines on patients with cancer treated with ICI. Outcomes of interest included seroconversion, SARS-CoV-2 infection rate, severe COVID-19, COVID-19 mortality rate. Incidence of ICI irAEs was also ascertained as well as vaccine adverse events. A meta-analysis was conducted to estimate the pooled effect sizes of the outcomes when possible, using random effects models. RESULTS: Overall, 19 studies were included for the analysis (n=10 865 with 2477 receiving ICI). We analyzed 15 cohort studies, 1 cross-sectional study, and 3 case reports. There were no statistically significant differences in seroconversion rates after the second dose of the vaccine when comparing patients with cancer receiving ICI with patients without cancer (risk ratio, RR 0.97, 95% CI 0.92 to 1.03) or with patients with cancer without active treatment (RR 1.00, 95% CI 0.96 to 1.04). There was a higher probability of seroconversion in patients with cancer treated with ICI compared with patients with cancer treated with chemotherapy (RR 1.09, 95% CI 1.00 to 1.18). In a single study in patients receiving ICI, no differences were observed in risk of irAE between those receiving inactivated vaccine and those unvaccinated (pneumonitis RR 0.88, 95% CI 0.33 to 2.3; rash RR 1.03, 95% CI 0.66 to 1.62; arthralgia RR 0.94, 95% CI 0.51 to 1.75). There were no studies for other types of vaccines comparing vaccinated vs not vaccinated in patients treated with ICI. The most common vaccine-related adverse events were local pain or fatigue. Overall, the quality of evidence was rated as very low. CONCLUSION: COVID-19 vaccination appears to be effective and safe in patients with cancer receiving ICI.

Immune responses to SARS-CoV-2 in vaccinated patients receiving checkpoint blockade immunotherapy for cancer.

Vaccination against SARS-CoV-2 has been successful in protecting patients with cancer from severe infections, but how immune responses against COVID-19 vaccination interact with those elicited during cancer immunotherapy has not been fully described. Immune checkpoint blockade (ICB) disrupts inhibitory pathways in immune cells to improve function and induce tumor immunity but can often cause serious immune related adverse events (IRAEs). Because COVID-19 vaccination and ICB both boost immune responses, it is imperative to understand if combining these regimens causes synergistic enhancement of the immune system. Specifically, whether ICB impacts anti-vaccine immunity in previously vaccinated patients is important since a large percentage of newly diagnosed cancer patients eligible for immunotherapy will have already been vaccinated against COVID-19. To address this, we investigated the influence of ICB on SARS-CoV-2-spike protein (SP) antibody titers and T cell responses in cancer patients previously vaccinated against COVID-19. Human blood samples were collected from 29 vaccinated patients and 12 unvaccinated control patients at baseline (prior to ICB) and following two rounds of ICB infusion. Anti-SARS-CoV-2-SP IgG titers and T cell responses were quantified. Compared to responses at baseline, there was no significant difference in these immune responses after immunotherapy in vaccinated individuals (P=0.4583, P=0.4571, respectively). We interpret these results as evidence that ICB immunotherapy does not significantly enhance SARS-CoV-2-specific antibody titers or T cell responses. Although our study lacks corresponding IRAE rates, the results provide humoral and cellular immunological data that support recent reports documenting the clinical safety and efficacy of COVID-19 vaccination in patients receiving ICB. Additional longitudinal prospective studies, such as the VOICE study (ClinicalTrials.gov identifier NCT04715438) and CAPTURE study (ClinicalTrials.gov identifier NCT03226886), are warranted and will provide broader safety and immunological data defining the effect of systemic cancer therapies on COVID-19 immunity.

Immune-Related Adverse Events Among COVID-19-Vaccinated Patients With Cancer Receiving Immune Checkpoint Blockade.

BACKGROUND: Whether COVID-19 vaccination and the associated immune response increases susceptibility to immune-related adverse events (irAEs) among patients treated with immune checkpoint inhibition (ICI) remains unknown. Short-term follow-up can assess the safety of concurrent administration of the vaccine and ICI treatment. METHODS: We conducted an electronic health record analysis of a cohort of 408 patients with cancer receiving ICI therapy and who were vaccinated for COVID-19 between January 16 and March 27, 2021. Patients were seen in follow-up for 90 days from the day of the first dose in this single-institution tertiary care center. We evaluated the incidence of irAEs and the frequency of each event type and grade among patients who experienced an irAE. We also evaluated the incidence of irAEs in patients who began a new immunotherapy agent after vaccination. RESULTS: Among 408 patients with cancer receiving ICI therapy (median age, 71 years; 217 [53%] male), administration of a COVID-19 mRNA vaccine within 90 days of ICI treatment was not associated with an increased incidence of irAEs. A total of 27 (7%) patients experienced a new irAE within the observation period. Among patients with previous irAEs from ICIs (n=54), 3 (6%) experienced a recurrent irAE, and of those initiating a new immunotherapy (n=52), 9 (17%) experienced an irAE. No excess risk of COVID-19 diagnosis was seen in this subset of patients receiving ICI therapy, and no breakthrough COVID-19 cases were seen after full COVID-19 vaccination. CONCLUSIONS: These findings should reassure providers that COVID-19 vaccination during ICI therapy is safe and efficacious.

A Single Center Retrospective Study of the Impact of COVID-19 Infection on Immune-related Adverse Events in Cancer Patients Receiving Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) can cause a variety of immune-related adverse events (irAEs). The coronavirus disease 2019 (COVID-19) is associated with increased amounts of pro-inflammatory cytokines, which may affect the outcome of irAEs. Data are limited regarding the impact of COVID-19 on irAEs in ICI-treated cancer patients. Hence, in this study, we retrospectively analyzed ICI-treated adult patients with malignant solid tumors at a single institution between August 2020 and August 2021. Patients who had the most recent ICI treatment over 1-month before or after the positive COVID-19 test were excluded from the study. For the COVID-19 positive group, only the irAEs that developed after COVID-19 infection were considered as events. A total of 579 patients were included in our study, with 46 (7.9%) in the COVID-19 positive group and 533 (92.1%) in the COVID-19 negative group. The baseline characteristics of patients in the 2 groups were similar. With a median follow-up of 331 days (range: 21-2226), we noticed a nonsignificant higher incidence of all-grade irAEs in the COVID-19 positive group (30.4% vs. 19.9%, P =0.18). The incidence of grade 3 and 4 irAEs was significantly higher in the COVID-19 positive group (10.9% vs. 3.2%, P =0.02). Multivariate analysis confirmed the association between COVID-19 infection and increased risk of severe irAE development (odds ratio: 1.08, 95% confidence interval: 1.02-1.14, P =0.01). Our study suggested that COVID-19 may pose a risk of severe irAEs in cancer patients receiving ICIs. Close monitoring and possibly delaying ICI administration could be considered when cancer patients are infected with COVID-19.

Role of cardiac MRI in the diagnosis of immune checkpoint inhibitor-associated myocarditis.

Immune checkpoint inhibitor (ICI)-induced cardiotoxicity is a rare immune-related adverse event (irAE) characterized by a high mortality rate. From a pathological point of view, this condition can result from a series of causes, including binding of ICIs to target molecules on nonlymphocytic cells, cross-reaction of T lymphocytes against tumor antigens with off-target tissues, generation of autoantibodies and production of proinflammatory cytokines. The diagnosis of ICI-induced cardiotoxicity can be challenging, and cardiac magnetic resonance (CMR) represents the diagnostic tool of choice in clinically stable patients with suspected myocarditis. CMR is gaining a central role in diagnosis and monitoring of cardiovascular damage in cancer patients, and it is entering international cardiology and oncology guidelines. In this narrative review, we summarized the clinical aspects of ICI-associated myocarditis, highlighting its radiological aspects and proposing a novel algorithm for the use of CMR.

Immune checkpoint inhibitors in kidney transplant recipients: a multicentre, single-arm, phase 1 study.

BACKGROUND: Most kidney transplant recipients with cancer stop or reduce immunosuppressive therapy before starting treatment with an immune checkpoint inhibitor, and approximately 40% of such patients will develop allograft rejection. Isolated immunosuppression reduction might be associated with organ rejection. Whether immunosuppression manipulation, immune checkpoint inhibition, or both, induce organ rejection is difficult to ascertain. The aim of this study was to examine the risk of allograft rejection with immune checkpoint inhibitor exposure when baseline immunosuppression was left unchanged. METHODS: We conducted a multicentre, single-arm, phase 1 study in three hospitals in Australia. Kidney transplant recipients aged 18 years or older with incurable, locally advanced cancer or defined metastatic solid tumours were eligible if they had a creatinine concentration of less than 180 mmol/L, no or low concentrations of donor-specific HLA antibodies, and an Eastern Cooperative Oncology Group status of 0-2. Patients received standard doses of nivolumab (3 mg/kg intravenously every 14 days for five cycles, then 480 mg every 28 days for up to 2 years). The primary endpoint was the proportion of patients with irretrievable allograft rejection and no evidence of tumour response. Primary outcome analyses and safety analyses were done in the modified intention-to-treat population. This trial is registered with the Australian and New Zealand Clinical Trials Register, ANZCTR12617000741381, and is completed. FINDINGS: Between May 31, 2017, and Aug 6, 2021, 22 kidney transplant recipients with various solid tumours were screened and enrolled, four of whom chose not to proceed in the study and one of whom had unexpected disease progression. 17 patients (six [35%] women and 11 [65%] men; median age 67 years [IQR 59-71]) were allocated treatment with nivolumab and were included in the analyses. The trial was then stopped due to ongoing difficulties with running clinical trials during COVID-19 health restrictions. Patients were treated with a median of three infusions (IQR 2-10) and median follow-up was 28 months (IQR 16-34). No patients had irretrievable allograft rejection without evidence of tumour response. There were no treatment-related deaths or treatment-related serious adverse events. The most common grade 3 or grade 4 adverse events were decreased lymphocyte count in four (24%) patients, fever or infection in four (24%) patients, decreased haemoglobin in three (18%) patients, and increased creatinine in three (18%) patients. INTERPRETATION: Maintaining baseline immunosuppression before treatment with an immune checkpoint inhibitor in kidney transplant recipients might not affect expected efficacy and might reduce the risk of allograft rejection mediated by immune checkpoint inhibitors. FUNDING: Bristol Myers Squibb.

Risk factors for pneumonitis in advanced extrapulmonary cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: Immune-mediated pneumonitis has a high mortality rate; however, information regarding the related risk factors remains limited. This study aimed to analyze risk factors for pneumonitis, including smoking and lung metastasis (LM), in patients with extrapulmonary primary tumors. METHODS: Data of 110 patients treated with immune checkpoint inhibitors (ICIs) (nivolumab/pembrolizumab) for treating extrapulmonary primary tumors at the Shiga University of Medical Science Hospital between January 2015 and December 2019 were retrospectively collected. The association between the onset of pneumonitis and treatment-related factors was analyzed by logistic regression. The severity of pneumonitis was graded according to the Common Terminology Criteria for Adverse Events version 5.0. Risk factors, such as the absence or presence of interstitial lung disease (ILD) and LM, or other clinical factors, including smoking status before ICI administration, were analyzed. RESULTS: Multivariate analyses indicated that the amount of smoking was significantly associated with an increase in the development of all-grade pneumonitis types (odds ratio (OR) = 20.33, 95% confidence interval (CI) = 20.03-20.66; p = 0.029). LM and ILD were significantly related to an increase in the development of symptomatic pneumonitis (≥ Grade 2) (OR = 10.08, 95% CI = 1.69-199.81; p = 0.076, and OR = 6.76, 95% CI = 1.13-40.63; p = 0.037, respectively). CONCLUSIONS: Pre-screening for ILD and LM and recognizing patients' smoking history is important for determining the risk of ICI-induced pneumonitis and allowing safe ICI administration.

Type 1 Diabetes Mellitus Associated with Nivolumab after Second SARS-CoV-2 Vaccination, Japan.

Recently, along with increasing use of immune checkpoint inhibitors such as nivolumab, the incidence of immune-related adverse events, including type 1 diabetes mellitus, has become a serious problem. We report a patient who had immune checkpoint inhibitor‒associated type 1 diabetes mellitus that developed after a second mRNA-based SARS-CoV-2 vaccination.

Safety and Efficacy of Extended Interval Dosing for Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer During the COVID-19 Pandemic.

INTRODUCTION: Extended interval (EI) dosing for immune checkpoint inhibitor (ICI) mono- or consolidation therapy initiated due to the COVID-19 pandemic led to a significant reduction in ICI-related site visits for patients with stage III and IV non-small cell lung cancer. Here we report the safety and efficacy compared to standard dose (SD) schedules. METHOD: In this retrospective analysis, patients who received ICI mono- or consolidation therapy, or adjuvant ICI therapy were assessed. Safety and efficacy of EI dosing with data of SD schedules were compared. RESULTS: One hundred seventeen patients received EI dosing for ICI and 88 patients SD. Patient characteristics were comparable. We observed 237 adverse events in the EI dosing cohort versus 118 in the SD group (P= .02). Overall, there was no difference in the occurrence of grade ≥3 adverse events (EI dosing: 21/237 [8.9%]; SD group: 20/118 [17.0%], P = .42), except for the pembrolizumab EI dosing cohort. Of all patients who received an EI dosing schedule, however, only 8 (6.8%) were reduced to SD because of toxicity. In 5 (4.3%) patients ICI was permanently stopped because of severe toxicity compared to 11 (12.5%) discontinuations in the SD group. Short-term treatment interruption occurred with similar frequencies in both groups. Progression-free survival and overall survival were comparable in patients receiving pembrolizumab and in those receiving adjuvant durvalumab. Progression-free survival and OS were better in the EI dosing cohort of nivolumab. CONCLUSION: EI dosing for ICI did not lead to an increase of clinically relevant toxicities resulting in dose reduction and/or treatment discontinuation. Efficacy of EI dosing of pembrolizumab and durvalumab were comparable to SD. Based on our safety and efficacy data EI dosing for ICI seems a safe and effective strategy.

COVID-19 vaccination and cancer immunotherapy: should they stick together?

The combination of COVID-19 vaccination with immunotherapy by checkpoint inhibitors in cancer patients could intensify immunological stimulation with potential reciprocal benefits. Here, we examine more closely the possible adverse events that can arise in each treatment modality. Our conclusion is that caution should be exercised when combining both treatments.

Influenza vaccination in cancer patients receiving immune checkpoint inhibitors: A systematic review.

BACKGROUND: There is a concern that influenza vaccination may increase the incidence of immune-related adverse events in patients receiving immune checkpoint inhibitors (ICIs). The aim of this systematic review was to summarize the available data on the safety and efficacy of influenza vaccination in cancer patients receiving ICIs. METHODS: Studies reporting safety and efficacy outcomes of influenza vaccination in cancer patients receiving ICIs were included. Only descriptive statistics were conducted to obtain a pooled rate of immune-related adverse events in vaccinated patients. RESULTS: Ten studies assessing the safety and eight assessing the efficacy of influenza vaccination in cancer patients receiving ICIs were identified, for a total of 1124 and 986 vaccinated patients, respectively. Most patients had melanoma or lung cancer and received a single agent anti-PD-1, but also other tumour types and immunotherapy combinations were represented. No severe vaccination-related toxicities were reported. The pooled incidence of any grade immune checkpoint inhibitor-related adverse events was 28.9%. In the 6 studies specifying the incidence of grade 3-4 toxicities, the pooled incidence was 7.5%. No grade 5 toxicities were reported. No pooled descriptive analysis was conducted in studies reporting efficacy outcomes due to the heterogeneity of endpoints and data reporting. Nevertheless, among the eight studies included, seven reported positive efficacy outcomes of influenza vaccination. CONCLUSION: The results of this systematic review support the safety and efficacy of influenza vaccination in cancer patients receiving ICIs. These results are particularly relevant in the context of the SARS-CoV-2 pandemic.

Cardiotoxicity of Immune Checkpoint Inhibitors.

PURPOSE OF REVIEW: Immune checkpoint inhibitors (ICIs) have improved the survival of several cancers. However, they may cause a wide range of immune-related adverse events (irAEs). While most irAEs are manageable with temporary cessation of ICI and immunosuppression, cardiovascular toxicity can be associated with high rates of morbidity and mortality. As ICIs evolve to include high-risk patients with preexisting cardiovascular risk factors and disease, the risk and relevance of ICI-associated cardiotoxicity may be even higher. RECENT FINDINGS: Several cardiovascular toxicities such as myocarditis, stress cardiomyopathy, and pericardial disease have been reported in association with ICIs. Recent findings also suggest an increased risk of atherosclerosis with ICI use. ICI-associated myocarditis usually occurs early after initiation and can be fulminant. A high index of suspicion is required for timely diagnosis. Prompt treatment with high-dose corticosteroids is shown to improve outcomes. Although the overall incidence is rare, ICI cardiotoxicity, particularly myocarditis, is associated with significant morbidity and mortality, making it a major therapy-limiting adverse event. Early recognition and prompt treatment with the cessation of ICI therapy and initiation of high-dose corticosteroids are crucial to improve outcomes. Cardio-oncologists will need to play an important role not just in the management of acute cardiotoxicity but also to reduce the risk of long-term sequelae.

Indications for and contraindications of immune checkpoint inhibitors in cancer patients with COVID-19 vaccination.

The COVID-19 pandemic has lasted over 1 year and will not disappear in a short time. There is no specific remedy against the virus as yet. Vaccination is thus far one of the most important strategies for preventing COVID-19. Cancer patients with COVID-19 have a higher mortality because of immunosuppression. Immune checkpoint inhibitors (ICIs) are a novel anticancer strategy for blocking inhibitory pathways, which are related to the immune response. There is a question regarding whether COVID-19 vaccination and ICI treatment impact each other in cancer patients. This review explores both sides of the relationship between ICI treatment and COVID-19 vaccination and suggests good efficacy and safety of ICI treatment after COVID-19 vaccination as well as little impact on the virus protection and toxicity associated with COVID-19 vaccination during ICI treatment.

Lay abstract The COVID-19 pandemic has lasted over 1 year. Vaccination is a promising strategy for preventing COVID-19. Cancer patients are prone to infection with COVID-19, and these patients have high mortality. Immune checkpoint inhibitors (ICIs) are a novel anticancer strategy. Whether COVID-19 vaccination and ICI treatment impact each other in cancer patients remains unknown. This review explores both sides of the relationship between ICI treatment and COVID-19 vaccination and suggests good efficacy and safety of ICI treatment after COVID-19 vaccination as well as little impact on the virus protection and toxicity associated with COVID-19 vaccination during ICI treatment.