ABSTRACT
Little is known on the long-lasting humoral response and the T cell activation induced by SARS-CoV-2 mRNA vaccines in patients with cancer. The study assessed the efficacy of the SARS-CoV-2 mRNA vaccines through measuring the seroconversion rate at pre-specified time points and the effect on the T cell immunity in patients with cancers. The study included 131 adult patients with solid or hematological cancer, who received SARS-CoV-2 mRNA vaccines. 96.2% of them exhibited adequate antibody response to the SARS-CoV-2 mRNA vaccines 2 months after the booster dose. SARS-CoV-2 mRNA vaccines could induce T cell activation; however, this is more likely in patients who have a positive seroconversion (94%) compared with the patients who did not (50%). Further research into the clinical relevance of low antibodies titers and lack of T cell activity is required to set up an effective vaccination strategy within this group of patients.
ABSTRACT
BACKGROUND: Oncological patients have a higher risk of prolonged SARS-CoV-2 shedding, which, in turn, can lead to evolutionary mutations and emergence of novel viral variants. The aim of this study was to analyze biological samples of a cohort of oncological patients by deep sequencing to detect any significant viral mutations. METHODS: High-throughput sequencing was performed on selected samples from a SARS-CoV-2-positive oncological patient cohort. Analysis of variants and minority variants was performed using a validated bioinformatics pipeline. RESULTS: Among 54 oncological patients, we analyzed 12 samples of 6 patients, either serial nasopharyngeal swab samples or samples from the upper and lower respiratory tracts, by high-throughput sequencing. We identified amino acid changes D614G and P4715L as well as mutations at nucleotide positions 241 and 3037 in all samples. There were no other significant mutations, but we observed intra-host evolution in some minority variants, mainly in the ORF1ab gene. There was no significant mutation identified in the spike region and no minority variants common to several hosts. CONCLUSIONS: There was no major and rapid evolution of viral strains in this oncological patient cohort, but there was minority variant evolution, reflecting a dynamic pattern of quasi-species replication.
ABSTRACT
Patients with cancer experience a higher burden of SARS-CoV-2 infection, disease severity, complications, and mortality, than the general population. SARS-CoV-2 mRNA vaccines are highly effective in the general population; however, few data are available on their efficacy in patients with cancer. Using a prospective cohort, we assessed the seroconversion rates and anti-SARS-CoV-2 spike protein antibody titers following the first and second dose of BNT162b2 and mRNA-1273 SARS-CoV-2 vaccines in patients with cancer in US and Europe from January to April 2021. Among 131 patients, most (94%) achieved seroconversion after receipt of two vaccine doses. Seroconversion rates and antibody titers in patients with hematological malignancy were significantly lower than those with solid tumors. None of the patients with history of anti-CD-20 antibody in the 6 months before vaccination developed antibody response. Antibody titers were highest for clinical surveillance or endocrine therapy groups and lowest for cytotoxic chemotherapy or monoclonal antibody groups.