Related Experiment Video
Updated: May 7, 2025
Detection of Polyfunctional T Cells in Children Vaccinated with Japanese Encephalitis Vaccine via the Flow Cytometry Technique
Published on: September 23, 2022
Immunogenicity of the CoronaVac vaccine in children: a real-world study
Wbeimar Aguilar-Jimenez1, Ana Lucia Rodriguez-Perea1, Mateo Chvatal-Medina1
1Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.
Insights
CoronaVac vaccination in children generates strong antibody and T-cell responses against COVID-19 variants. While these immune responses decrease over time, especially against Omicron, booster doses may be needed.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
- Infectious Diseases
Background:
- Limited real-world data exist on CoronaVac immunogenicity in children, particularly concerning SARS-CoV-2 variants in lower-income settings.
- This study addresses the need for real-world evidence on CoronaVac's immune response in pediatric populations.
- Evaluating immunogenicity stratified by prior SARS-CoV-2 exposure is crucial for understanding vaccine effectiveness.
Purpose of the Study:
- To evaluate the immunogenicity of CoronaVac in Colombian children aged 3-11 years.
- To assess the impact of previous SARS-CoV-2 exposure on vaccine response.
- To analyze humoral and cellular immunity against various SARS-CoV-2 variants post-vaccination.
Main Methods:
- Enrolled 89 children (3-11 years), divided into previously exposed and non-exposed groups.
- Collected saliva for infection monitoring and blood for immunogenicity assessment at 2 and 6 months.
- Measured total IgG and IgA antibodies, neutralizing titers against variants (B.1, Delta, Mu, Omicron), and T-cell responses via flow cytometry.
Main Results:
- CoronaVac was well-tolerated with low infection rates (7.8%) in both groups.
- Induced robust IgG, IgA, and neutralizing antibody responses against all tested variants, with titers generally above 20, despite some waning.
- Generated a polyfunctional T-cell response (IFN-γ/TNF-α, cytotoxic molecules) in CD4+ and CD8+ T-cells, more pronounced in CD4+ cells, which persisted for 6 months, though reduced against Omicron.
Conclusions:
- CoronaVac elicits significant humoral and cellular immune responses in children, demonstrating cross-recognition of SARS-CoV-2 variants.
- Immune responses wane over time and are reduced against newer variants like Omicron.
- Findings suggest the potential need for booster vaccinations to maintain protection, especially in the context of evolving viral strains.
Background:
Despite its proven effectiveness and safety, there are limited real-world data on CoronaVac's immunogenicity in children, especially in lower-income countries, particularly for SARS-CoV-2 variants. We present a real-world study evaluating CoronaVac's immunogenicity in Colombian children stratified by previous exposure to this virus.
Methods:
89 children aged 3-11 years were enrolled (50 Non-Exposed and 39 Exposed). Saliva samples were collected every 15 days to monitor potential SARS-CoV-2 infection, and blood samples were taken at two and six months after vaccination, to evaluate immunogenicity. Total IgG and IgA antibodies were measured by ELISA, and neutralizing titers against B.1, Delta, Mu, and Omicron variants were assessed by plaque reduction assay. T-cells were stimulated with wild-type and Omicron peptide pools to analyze activation-induced markers, memory phenotype, cytotoxic molecules, and cytokine production by flow cytometry.
Findings:
CoronaVac was well tolerated, with only 7.8% infection incidence in both Exposed and Non-Exposed groups. It elicits a robust humoral response through IgG, IgA, and neutralizing antibodies against all variants. Despite waning, most participants maintained neutralizing titers ≥20 over time. CoronaVac also induced a polyfunctional cellular response against various strains, albeit reduced against Omicron, regardless of prior exposure. This response, characterized by IFN-γ/TNF-α and cytotoxic molecule production, was more pronounced in CD4+ than in CD8+ T-cells and remained detectable even after 6 months.
Interpretation:
CoronaVac induces robust humoral and cellular immune responses against various variants in children, suggesting cross-recognition. However, these responses diminish over time, particularly in the context of variants, indicating the need for booster doses.
More Related Videos
09:01An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
07:05In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model
Published on: November 28, 2017
