Studies show an increased incidence of SARS-CoV-2 omicron breakthrough infections in cancer patients

In a recently published article in the journal cancer cell, Scientists have shown the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in cancer patients living in Austria and Italy. This study reveals the induction of breakthrough infections of Omicron in patients with hematological and solid tumors.

Background

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) pandemic, causes severe infections in immunocompromised patients, including cancer patients. I know that.In addition, a relatively low level Neutralizing antibody It has also been observed in cancer patients, especially those receiving B cell targeting therapy, in response to the COVID-19 vaccine.

With the advent of improved immunocompatibility SARS-CoV-2 mutants, such as the Delta and Omicron mutants, breakthrough infections have increased sharply even in fully vaccinated individuals. However, vaccines are still highly protective against severe and deadly infections. The COVID-19 vaccine has shown acceptable efficacy for serious illness, even in cancer patients infected with Omicron. However, quarantine and quarantine measures associated with SARS-CoV-2 infection can impair routine administration of anticancer therapy and may reduce the survival prognosis of cancer patients.

In the current study, scientists evaluated the incidence of SARS-CoV-2 infection in cancer patients throughout the pandemic.

Research design

The study included 3,959 cancer patients, 77% of whom had solid cancer and 23% had hematological cancer. Approximately 69% of patients did not receive anticancer treatment at the time of COVID-19 vaccination. In terms of vaccination rates, about 85% of patients were vaccinated at least once and 15% remained unvaccinated. The incidence of SARS-CoV-2 infection in these patients was assessed between February 2020 and 2022.

Important findings

SARS-CoV-2 infection was detected in approximately 24% of patients during the study period. Vaccine breakthrough infections were observed in 43% of patients during the Delta-dominated wave. In contrast, a significantly higher rate (70%) of breakthrough infections was observed among patients during the Omicron-dominated wave. Cancer patients receiving systemic anticancer treatment for both delta and omicron waves had a significantly higher rate of breakthrough infections than untreated patients (83% vs. 56%).

Regardless of vaccination status, COVID-19-related hospitalizations were more frequent with delta waves than with omicron waves in terms of disease severity. However, relatively shorter lengths of stay were observed in vaccinated patients compared to unvaccinated patients. In addition, only 9% of patients with breakthrough infections were admitted to the intensive care unit (ICU).This emphasizes protection Effectiveness of COVID-19 vaccine for severe illness.

Humoral immune response to vaccination

To determine vaccine-induced antibody responses to delta and omicron variants, scientists measured blood levels of anti-delta and anti-omicron spike receptor-binding domain (RBD) antibodies in a total of 78 cancer patients. The analysis also includes 25 healthcare professionals as controls.

In response to vaccination, healthcare professionals showed higher levels of total anti-spiky antibody compared to cancer patients. The lowest levels of wild-type RBD-specific antibodies were observed in patients with hematological cancer receiving B cell-targeted therapy, followed by patients with hematological malignancies and solid tumors who did not receive B-cell targeted therapy. Similar trends were observed with delta and omicron-specific spike RBD antibodies.

Serum samples collected from hematological and solid tumor patients who have not received B-cell targeted treatment are between wild-type / delta RBD and angiotensin converting enzyme 2 (ACE2; host cell receptor for viral entry). Significantly inhibited the interaction. However, significantly lower levels of inhibition were observed in patients receiving treatment targeting B cells. Importantly, a significant reduction in inhibition of Omicron RBD-ACE2 interaction was observed in all patients with solid tumors and hematological malignancies.

Significance of research

This study shows that the incidence of breakthrough infections in vaccines is high, but the severity of illness in patients with solid tumors and hematological malignancies is reduced during the omicron wave compared to the delta wave. ..

The study also emphasizes that the antibody response induced by the COVID-19 vaccine is lower in cancer patients than in healthy individuals. The reduction in antibody response is highest among blood patients receiving treatment targeting B cells. Overall, significant impairment of vaccine-induced Omicron neutralization has been observed in cancer patients.