Humoral and cellular immune response after mRNA SARS-CoV-2 vaccine in children on treatment for cancer: A pilot observational study

• Published in: Heliyon Vol. 10; no. 14; p. e34503
• Main Authors: Mastronuzzi, Angela, Carsetti, Rita, De Ioris, Maria Antonietta, Agrati, Chiara, Del Baldo, Giada, Russo, Cristina, Cefalo, Maria Giuseppina, Merli, Pietro, Perno, Carlo Federico, dell'Anna, Vito Andrea, Serra, Annalisa, Bordoni, Veronica, Piano Mortari, Eva, Marcellini, Valentina, Albano, Christian, Linardos, Giulia, Costabile, Valentino, Sinibaldi, Matilde, Guercio, Marika, di Cecca, Stefano, Quintarelli, Concetta, Locatelli, Franco
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.07.2024; Elsevier
• Subjects: Cancer; Children; Humoral immunity; SARS-CoV-2 mRNA vaccine; T-cell immunity; T-cell immunity; SARS-CoV-2 mRNA vaccine; Children; Humoral immunity; Cancer
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e34503

Immunocompromised children are at risk of developing severe COVID-19 infection. We conducted a pilot prospective study to evaluate the impact of cancer treatment and stem cell transplantation on immunogenicity of two doses of BNT162b2 vaccine in pediatric patients. Humoral, B- and T-cell responses to the BNT162b2 vaccine were assessed before, after the first and the second dose in patients aged 5–12 years (n = 35) and in a group of healthy donors (HD, n = 12). Patients were divided in three groups: solid tumors (ST, n = 11), hematological malignancies (HM, n = 14) and Hematopoietic Stem Cell Transplantation (HSCT) recipients (n = 10). After two vaccine doses, the seroconversion rate was 79.3 % (72.7 % in ST, 66.7 % in HM and 100 % in HSCT). The antibodies production was not associated to the presence of memory B and T-cells. Memory B-cells were measurable in 45.5 % ST, 66.6 % HSCT and in 22.0 % HM. The specific T-cell response was observed in most ST (81.8 %) and HSCT (85.7 %) patients and at lesser extent in those with HM (55.5 %). The combination of all immunological parameters (antibodies, memory B and T cells) showed that a significant fraction of HM (33.3 %) and ST (18.2 %) patients completely failed to respond to vaccination. Although able to produce antibodies, 11.1 % of HM and 27.3 % of ST had no B- and T-cell memory. HSCT subgroup showed the best immune function, with 80 % complete response and optimal T-cell function. Combination of anti-RBD antibody, and specific memory B- and T-cell responses represents a reliable read-out of vaccine immune efficacy in frail patients.