A study in Microbiology Spectrum investigated the immune response to the SARS-CoV-2 vaccine in cancer patients compared to healthy individuals, revealing that while both groups developed strong cellular and humoral immune responses, those without cancer exhibited higher immunogenicity. Despite B-cell targeted therapies potentially lowering antibody responses, they didn't significantly affect T-cell responses, highlighting vaccination's effectiveness in inducing protective immunity against COVID-19 in both populations.
In the study, 98% of immunocompetent participants and 81% of immunocompromised participants exhibited elevated receptor binding domain (RBD) antibody titers, with 60% of immunocompetent and 44% of immunocompromised individuals also displaying elevated T-cell responses. Notably, enhanced T-cell responses were more prevalent among individuals with prior SARS-CoV-2 infection or Long-COVID, indicating significant differences in T-cell response levels between immunocompetent individuals and those with carcinoma, though such differences were not observed between immunocompetent individuals and those with hematologic malignancies. Furthermore, among the immunocompromised group, those who had recently undergone cancer treatment demonstrated distinct immune response patterns, suggesting the nuanced impact of cancer treatment on vaccine-induced immunity.
“Our data support the concept of a suppressive role of B-cell targeted therapies on antibody responses, but do not indicate any implications on parallel T-cell responses in those same individuals,” investigators wrote. “Those receiving B-cell targeted therapies were present in both the hematologic malignancy and carcinoma cohorts. Within these immunocompromised sub-cohorts, widespread variance in antibody responses was observed and may be attributed to the length of time since the patient’s last immunosuppressive treatment. As a result, vaccinated patients receiving B-cell targeted therapies seem to derive clinical benefit from administration of SARS-CoV-2 monoclonal or polyclonal antibody preparations to increase humoral immunity.”1
3 Key Takeaways
- Both cancer patients and healthy individuals developed robust cellular and humoral immune responses to the SARS-CoV-2 vaccine, although immunogenicity was higher among those without cancer.
- Despite concerns that B-cell targeted therapies might dampen antibody responses, the study found they did not significantly affect T-cell responses.
- The study highlights the importance of further investigations into the vaccine's effectiveness among immunocompromised populations, particularly to understand the full scope of T-cell responses and the impact of various cancer treatments on vaccine-induced immunity.
The research examined the immune responses of immunocompetent individuals (those without any underlying disorders, n = 479) versus immunocompromised individuals (those with underlying conditions, notably cancer, n = 115) who received the SARS-CoV-2 vaccine. It centered on assessing antibody levels against the RBD and the SARS-CoV-2 spike protein, alongside T-cell responses. Participants COVID-19 status ranged from unknown infection history to previous infection, to Long-COVID cases.
“19% (49/410) of participants who reported never having COVID-19 were reactive for N SARS-CoV-2 antibodies,” investigators wrote. “This suggests that these participants had been unknowingly infected with SARS-CoV-2, which is consistent with earlier studies that reported approximately 40% of SARS-CoV-2 infected patients with similar exposure histories, and treatment were asymptomatic (37). Despite having overall lower viral burdens and shedding virus for a shorter time than symptomatic patients, asymptomatic persons are still able to transmit the virus, which emphasizes the need for continued SARS-CoV-2 surveillance.”1
This study's constraints stem from the lack of detailed information on diagnosis, treatment, and the status of SARS-CoV-2 infection, elements that merit additional exploration to assess their impact on diminishing T-cell responses. The limited sample size (n = 12), coupled with the consistent T-cell responses within the carcinoma group, underscores the importance of conducting future research aimed at enrolling more individuals from this cohort to confirm these findings. Moreover, it is advisable to further investigate the effects of conditions that disrupt normal immune function on the enhancement of T-cell responses.
Although humoral immunity serves as an indicator of protection against SARS-CoV-2, assessments of cellular immunity might also be necessary to fully understand the immune status of at-risk immunocompromised individuals, particularly those cancer patients receiving treatment.
Reference
1. Titova E, Kan V, Lozy T, Ip A, Shier K, et. al. Humoral and cellular immune responses against SARS-CoV-2 post-vaccination in immunocompetent and immunocompromised cancer populations. Microbiology Spectrum. Published February 14, 2024. Accessed February 20, 2024. DOI: https://doi.org/10.1128/spectrum.02050-23
