Tweet
Curr Microbiol
. 2025 Dec 9;83(1):61.
doi: 10.1007/s00284-025-04627-x. Persistence of SARS-CoV-2 S IgG Antibodies in Children Post-COVID-19 and the Association of Antibody Levels with Vaccination Status
Eduardo L López 1 , María S Tineo 2 , Federico Di Gregorio 3 , María F Pavan 4 5 , Florencia A Bonnin 3 6 7 , Lidia E Torrado 2 , Paola J Karp 4 , Analía Toledano 3 , Ana Caratozzolo 3 , Sergio I Nemirovsky 8 , María M Contrini 2 , Lorena I Ibañez 4 , Laura B Talarico 9 10
Affiliations
Children who contracted COVID-19 develop antibodies targeting the SARS-CoV-2 spike (S) protein which persist for 4 to 12 months following infection. We sought to analyze the antibody response to SARS-CoV-2 one year after COVID-19 in children under 18 years, vaccinated or unvaccinated. Blood samples were collected during the acute phase, the convalescence stage and one-year post-disease. Vaccinated adults who had COVID-19 during the same timeframe were analyzed for comparison. Serum SARS-CoV-2 S IgG was assessed using immunoassay, and neutralizing activity was evaluated using a SARS-CoV-2 S-pseudotyped lentivirus assay. Seventy-five children were enrolled, with a median age of 8 years (IQR 3-12), and 35% were vaccinated. Forty-nine adults were included, with a median age of 34 years (IQR 29-44). Among unvaccinated children, median SARS-CoV-2 S IgG levels one year after COVID-19 tended to decrease 2-fold compared to convalescent levels. SARS-CoV-2 antibodies were notably elevated in children with two or three COVID-19 vaccine doses compared to unvaccinated individuals. Children who received mRNA vaccines exhibited higher SARS-CoV-2 IgG titers (p = 0.0028) and neutralizing antibodies (p = 0.0120) compared to those who received inactivated vaccines. SARS-CoV-2 IgG showed no correlation with the severity of the initial illness or the presence of comorbidities. SARS-CoV-2 IgG did not significantly differ between vaccinated children and adults with the same vaccination status. Among unvaccinated children, convalescent levels of IL-1 β and IL-4 positively correlated with one-year antibody responses. This work highlights the significance of vaccinating children to sustain a lasting humoral immune response against SARS-CoV-2, even after infection.
. 2025 Dec 9;83(1):61.
doi: 10.1007/s00284-025-04627-x. Persistence of SARS-CoV-2 S IgG Antibodies in Children Post-COVID-19 and the Association of Antibody Levels with Vaccination Status
Eduardo L López 1 , María S Tineo 2 , Federico Di Gregorio 3 , María F Pavan 4 5 , Florencia A Bonnin 3 6 7 , Lidia E Torrado 2 , Paola J Karp 4 , Analía Toledano 3 , Ana Caratozzolo 3 , Sergio I Nemirovsky 8 , María M Contrini 2 , Lorena I Ibañez 4 , Laura B Talarico 9 10
Affiliations
- PMID: 41364246
- DOI: 10.1007/s00284-025-04627-x
Children who contracted COVID-19 develop antibodies targeting the SARS-CoV-2 spike (S) protein which persist for 4 to 12 months following infection. We sought to analyze the antibody response to SARS-CoV-2 one year after COVID-19 in children under 18 years, vaccinated or unvaccinated. Blood samples were collected during the acute phase, the convalescence stage and one-year post-disease. Vaccinated adults who had COVID-19 during the same timeframe were analyzed for comparison. Serum SARS-CoV-2 S IgG was assessed using immunoassay, and neutralizing activity was evaluated using a SARS-CoV-2 S-pseudotyped lentivirus assay. Seventy-five children were enrolled, with a median age of 8 years (IQR 3-12), and 35% were vaccinated. Forty-nine adults were included, with a median age of 34 years (IQR 29-44). Among unvaccinated children, median SARS-CoV-2 S IgG levels one year after COVID-19 tended to decrease 2-fold compared to convalescent levels. SARS-CoV-2 antibodies were notably elevated in children with two or three COVID-19 vaccine doses compared to unvaccinated individuals. Children who received mRNA vaccines exhibited higher SARS-CoV-2 IgG titers (p = 0.0028) and neutralizing antibodies (p = 0.0120) compared to those who received inactivated vaccines. SARS-CoV-2 IgG showed no correlation with the severity of the initial illness or the presence of comorbidities. SARS-CoV-2 IgG did not significantly differ between vaccinated children and adults with the same vaccination status. Among unvaccinated children, convalescent levels of IL-1 β and IL-4 positively correlated with one-year antibody responses. This work highlights the significance of vaccinating children to sustain a lasting humoral immune response against SARS-CoV-2, even after infection.