T-cell responses to primary SARS-CoV-2 vaccination in Down syndrome - From childhood to adulthood

Area of Science:

• Immunology
• Genetics
• Virology

Background:

• Down syndrome (DS) is a common genetic disorder linked to increased COVID-19 pandemic risks.
• SARS-CoV-2 vaccine strategies involved age-dependent dosing, with younger children receiving lower doses.
• Previous studies noted age-dependent antibody responses in vaccinated children with DS, but cellular immunity was less understood.

Purpose of the Study:

• To evaluate vaccine-induced T-cell responses in children with Down syndrome after primary mRNA SARS-CoV-2 vaccination.
• To compare SARS-CoV-2-specific T-cell abundance and interferon-gamma (IFNγ) production across different age groups in individuals with DS.

Main Methods:

• Assessed SARS-CoV-2-specific T-cell abundance in 40 participants and IFNγ production in 55 participants aged 3-74 years.
• Stimulated T-cells with spike antigen and measured re-activation and cytokine production.
• Compared responses between age cohorts: children (5-11 years), adolescents (12-17 years), and adults.

Main Results:

• No significant difference in SARS-CoV-2-specific CD4+ T-cell re-activation was observed between adolescents and adults with DS.
• Children aged 5-11 years with DS showed significantly lower CD4+ T-cell re-activation compared to adolescents.
• Interferon-gamma (IFNγ) production levels were similar across all evaluated age groups.

Conclusions:

• Reduced SARS-CoV-2 mRNA vaccine dosing in children with DS (5-11 years) may correlate with diminished T-cell re-activation, in addition to previously noted lower antibody responses.
• Children with DS aged 5-11 years might benefit from receiving higher vaccine doses or boosters to achieve optimal immunity and protection.
• Further research is warranted to optimize COVID-19 vaccination strategies for individuals with Down syndrome.