background and objectives: mRNA vaccines elicit a durable humoral response to SARS-CoV-2 in adults, whereas evidence in children is scarce. this study aimed to assess the early and long-term immune response to the mRNA vaccine in children with or without previous SARS-CoV-2 infection. Methods: In a multicentre prospective observational study, we profiled the immune response to the Pfizer BioNTech (BNT162b2) vaccine in 5-11-year-old children attending the university pediatric hospital of padua and bambino-gesù hospital in rome (Italy) from december-2021 to february-2023. blood samples were collected pre-, 1-, and 6-months after vaccination. Neutralizing antibodies (NAbs) and anti-spike-receptor-binding-domain (anti-S-RBD) IgG titers were analyzed through plaque reduction neutralization test (PRNT) and chemiluminescent immune-enzymatic assay (CLIA), respectively. Immune cell phenotypes were analyzed by flow cytometry. results: sixty children (26 [43 %] female, median age = 8 years [IQR = 7-10.7]) were enrolled in the study, including 46 children with a laboratory-confirmed previous COVID-19 (SARS-CoV-2-recovered) and 14 SARS-CoV-2-naïve participants defined as the absence of antigen-specific antibodies before vaccination. SARS-CoV-2-recovered participants recorded higher anti-S-RBD IgG and Wild-type and omicron BA.2 NAbs titers than SARS-CoV-2-naïve participants at both 1- and 6-months after vaccination. antibody titers correlated with T (Tregs) and B (Bregs) regulatory cell frequencies in SARS-CoV-2-recovered children. both SARS-CoV-2-recovered and SARS-CoV-2-naïve participants decreased antibody titers by approximately 100 to 250 % from 1 to 6 months. while children with immunocompromising underlying conditions developed immune responses comparable to those of healthy children, solid organ transplant recipients exhibited lower levels of NAbs and anti-S-RBD IgG titers, as well as reduced frequencies of tregs and bregs. conclusions: mRNA vaccination triggered a higher production of specific anti-SARS-CoV-2 antibodies along with increased levels of regulatory cells in children with previous SARS-CoV-2 infection up to the following 6 months. these findings provide insights into boosting pre-existing immunity.
Di Chiara, C., Cantarutti, A., Raffaella Petrara, M., Bonfante, F., Benetti, E., Boracchini, R., et al. (2023). Stronger and durable SARS-CoV-2 immune response to mRNA vaccines in 5–11 years old children with prior COVID-19. VACCINE [10.1016/j.vaccine.2023.12.006].
Stronger and durable SARS-CoV-2 immune response to mRNA vaccines in 5–11 years old children with prior COVID-19
Nicola Cotugno;
2023-12-08
Abstract
background and objectives: mRNA vaccines elicit a durable humoral response to SARS-CoV-2 in adults, whereas evidence in children is scarce. this study aimed to assess the early and long-term immune response to the mRNA vaccine in children with or without previous SARS-CoV-2 infection. Methods: In a multicentre prospective observational study, we profiled the immune response to the Pfizer BioNTech (BNT162b2) vaccine in 5-11-year-old children attending the university pediatric hospital of padua and bambino-gesù hospital in rome (Italy) from december-2021 to february-2023. blood samples were collected pre-, 1-, and 6-months after vaccination. Neutralizing antibodies (NAbs) and anti-spike-receptor-binding-domain (anti-S-RBD) IgG titers were analyzed through plaque reduction neutralization test (PRNT) and chemiluminescent immune-enzymatic assay (CLIA), respectively. Immune cell phenotypes were analyzed by flow cytometry. results: sixty children (26 [43 %] female, median age = 8 years [IQR = 7-10.7]) were enrolled in the study, including 46 children with a laboratory-confirmed previous COVID-19 (SARS-CoV-2-recovered) and 14 SARS-CoV-2-naïve participants defined as the absence of antigen-specific antibodies before vaccination. SARS-CoV-2-recovered participants recorded higher anti-S-RBD IgG and Wild-type and omicron BA.2 NAbs titers than SARS-CoV-2-naïve participants at both 1- and 6-months after vaccination. antibody titers correlated with T (Tregs) and B (Bregs) regulatory cell frequencies in SARS-CoV-2-recovered children. both SARS-CoV-2-recovered and SARS-CoV-2-naïve participants decreased antibody titers by approximately 100 to 250 % from 1 to 6 months. while children with immunocompromising underlying conditions developed immune responses comparable to those of healthy children, solid organ transplant recipients exhibited lower levels of NAbs and anti-S-RBD IgG titers, as well as reduced frequencies of tregs and bregs. conclusions: mRNA vaccination triggered a higher production of specific anti-SARS-CoV-2 antibodies along with increased levels of regulatory cells in children with previous SARS-CoV-2 infection up to the following 6 months. these findings provide insights into boosting pre-existing immunity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
