In a recent article published in the magazine cancer prison cellScientists have confirmed the occurrence of SARS-CoV-2 infection of severe acute respiratory syndrome in cancer patients residing in Austria and Italy. The study reveals an induction in supernatant omicron infection in patients with leukemias and solid carcinomas.
Coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has been found to cause severe infections in immunocompromised patients, including cancer patients. Furthermore, a relatively low level of neutralizing antibodies has also been observed in response to COVID-19 vaccines in cancer patients, especially those receiving treatments targeting B cells.
The emergence of SARS-CoV-2 variants with improved immune fitness, such as delta and omicron variants, led to a sharp increase in penetrating infections even in fully vaccinated individuals. However, vaccines still show high protective efficacy against severe and fatal infections. COVID-19 vaccines have shown acceptable efficacy against severe disease, even in cancer patients with omicron. However, isolation and quarantine procedures associated with SARS-CoV-2 infection may impair the routine administration of anticancer therapy, which may reduce the prognosis and survival in cancer patients.
In the current study, scientists evaluated the incidence of SARS-CoV-2 infection in cancer patients throughout the epidemic.
The study included 3,959 cancer patients, 77% of whom had solid cancer, and 23% had leukemia. About 69% of patients had not received any anti-cancer therapy at the time of the COVID-19 vaccination. In terms of vaccine coverage, about 85% of patients received at least one dose of vaccine, and 15% remained unimmunized. The incidence of SARS-CoV-2 infection in these patients was evaluated between February 2020 and 2022.
SARS-CoV-2 infection was detected in approximately 24% of patients during the study period. During the delta-dominated wave, vaccine penetration infection was observed in 43% of patients. In contrast, a significantly higher incidence of penetrating infection (70%) was observed among patients during the omicron-dominated wave. During the delta and omicron waves, cancer patients receiving systemic anticancer therapy showed a significantly higher incidence of penetrating infection than those who did not (83% vs 56%).
Regarding disease severity regardless of vaccination status, a higher frequency of hospitalizations associated with COVID-19 was observed during the delta wave compared to that during the Omicron wave. However, a relatively shorter duration of hospital stay was observed in vaccinated patients compared to unvaccinated patients. In addition, only 9% of patients with serious infections were admitted to the intensive care unit (ICU). This highlights the preventive efficacy of COVID-19 vaccines against severe diseases.
Humoral immune response to vaccination
To determine the vaccine-induced antibody response against delta and omicron variants, the scientists measured blood levels of delta receptor-binding domain and anti-omicron (RBD) antibodies in a total of 78 cancer patients. In the analysis, they also included 25 health care workers as controls.
In response to vaccination, health care workers showed higher levels of total anti-spike antibodies than cancer patients. The lowest level of RBD-specific antibody was observed in leukemia patients receiving B-cell-directed therapy, followed by leukemia patients not receiving B-cell-directed therapy and patients with solid tumors. A similar trend was observed for the delta- and omicron-specific antibodies.
Serum samples collected from leukemia patients without B-cell-directed therapy and patients with solid tumors significantly inhibited the interaction between wildtype/delta RBD and angiotensin-converting enzyme 2 (ACE2; host cell receptor for viral entry). However, a significant decrease in the level of inhibition was observed for patients receiving B-cell-directed therapy. Importantly, a significant decrease in the inhibition of the Omicron RBD-ACE2 interaction was observed for all patients with solid tumors and leukemias.
Study the importance
The study shows an increased incidence of vaccinia penetrating infection but decreased disease severity among patients with solid tumors and leukemia during an omicron wave compared to a delta wave.
The study also highlights that the antibody response from the COVID-19 vaccine is lower in cancer patients than in healthy individuals. The decrease in antibody response is highest among hematological patients receiving B-cell-directed therapy. In general, a significant impairment of vaccine-induced omicron neutralization was observed in cancer patients.