RESUMEN
This study was conducted to investigate potential differences in vaccine efficacy between patients undergoing palliative chemotherapy and receiving adjuvant chemotherapy. Additionally, the study proved the influence of vaccination timing on vaccine efficacy during active chemotherapy. Anti-receptor-binding domain (RBD) IgG binding antibody assays and surrogate neutralizing antibody assays were performed after BNT162b2 or mRNA-1273 vaccination in 45 solid cancer patients (23 adjuvant and 22 palliative chemotherapy) and in 24 healthy controls before vaccination (baseline), at every two to four weeks after the first (post-dose 1) and the second vaccination (post-dose 2). The levels of anti-RBD IgG and neutralizing antibodies increased significantly from baseline through post-dose 1 to post-dose 2 in all three groups. At the post-dose 1, the anti-RBD IgG and neutralizing antibody levels were significantly lower in cancer patients than in healthy controls. However, by post-dose 2, the seropositivity of anti-RBD IgG and neutralizing antibodies uniformly reached 100% across all groups, with no significant disparity in antibody levels among the three groups. Moreover, the antibody titers were not significantly different between patients with a vaccine and chemotherapy interval of more than 14 days or those with less than 14 days. This study demonstrated that after second doses of mRNA COVID-19 vaccines, humoral immune responses in patients receiving chemotherapy were comparable to those of healthy controls, regardless of whether the purpose of the anti-cancer treatment was palliative or adjuvant. Furthermore, the timing of vaccination did not affect the level of humoral immunity after the second vaccination.
RESUMEN
Purpose@#Pneumococcal vaccination (13-valent pneumococcal conjugate vaccine [PCV13]) is recommended to cancer patients undergoing systemic chemotherapy. However, the optimal time interval between vaccine administration and initiation of chemotherapy has been little studied in adult patients with solid malignancies. @*Materials and Methods@#We conducted a prospective randomized controlled trial to evaluate whether administering PCV13 on the first day of chemotherapy is non-inferior to vaccinating 2 weeks prior to chemotherapy initiation. Patients were randomly assigned to two study arms, and serum samples were collected at baseline and 4 weeks after vaccination to analyze the serologic response against Streptococcus pneumoniae using a multiplexed opsonophagocytic killingassay. @*Results@#Of the 92 patients who underwent randomization, 43 patients in arm A (vaccination 2 weeks before chemotherapy) and 44 patients in arm B (vaccination on the first day of chemotherapy) were analyzed. Immunogenicity was assessed by geometric mean and fold-increase of post-vaccination titers, seroprotection rates (percentage of patients with post-vaccination titers > 1:64), and seroconversion rates (percentage of patients with > 4-fold increase in post-vaccination titers). Serologic responses to PCV13 did not differ significantly between the two study arms according to all three types of assessments. @*Conclusion@#The overall antibody response to PCV13 is adequate in patients with gastric and colorectal cancer during adjuvant chemotherapy, and no significant difference was found when patients were vaccinated two weeks before or on the day of chemotherapy initiation.