Antibody concentration and function following SARS-CoV-2 vaccination decrease with age in adults and children with...

Area of Science:

• Immunology
• Vaccinology
• Genetics

Background:

• Individuals with Down syndrome (DS) exhibit immune system alterations, leading to increased susceptibility to infections like SARS-CoV-2.
• Previous research indicated diminished antibody levels post-primary SARS-CoV-2 vaccination in adults with DS.
• This study prospectively examines antibody responses and functionality following primary and booster COVID-19 vaccination in both children and adults with DS.

Purpose of the Study:

• To evaluate and compare antibody concentrations and neutralizing titers after SARS-CoV-2 primary and booster vaccination in individuals with Down syndrome (DS) versus healthy controls (HC).
• To investigate the impact of age on vaccine response in individuals with DS.
• To determine if vaccine response defects in DS are consistent across different vaccine types (mRNA and vector-based).

Main Methods:

• Prospective study measuring anti-S and anti-RBD antibody concentrations and virus neutralizing titers (ID50) post-vaccination.
• Participants included adults (N=215 DS, N=93 HC) and children with DS, receiving mRNA or vector-based primary vaccines and mRNA boosters.
• Antibody levels and neutralization capacity were compared between DS and HC groups, and analyzed for age-related trends within the DS cohort.

Main Results:

• All participants showed increased antibody concentrations post-vaccination, but individuals with DS consistently had lower anti-S and anti-RBD antibody levels than HC, irrespective of primary vaccine type.
• In the DS group, anti-S antibody concentrations decreased with age; teenagers (12-17 years) had the highest levels, while younger children (<12 years) had significantly lower levels.
• Serum neutralization was significantly lower in adults with DS compared to HC after both mRNA and vector-based primary vaccination.

Conclusions:

• This is the first vaccine immunology study in Down syndrome (DS) encompassing both children and adults.
• Individuals with DS exhibit reduced antibody concentrations and serum neutralization following primary and booster SARS-CoV-2 vaccination compared to healthy controls.
• The observed vaccine response defects in DS are age-dependent, underscoring the need for age-specific immunization strategies in this population.