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Children develop robust and sustained cross-reactive spike-specific immune responses to SARS-CoV-2 infection
Alexander C Dowell1, Megan S Butler1, Elizabeth Jinks1
1Institute of Immunology & Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
Insights
Children exhibit stronger, cross-reactive, and sustained immune responses to SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) compared to adults. This robust immunity, particularly against the spike protein, offers insights into milder pediatric COVID-19 outcomes.
Area of Science:
- Immunology
- Virology
- Pediatrics
Background:
- SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infections are typically mild in children, but the underlying immunological reasons remain unclear.
- Understanding immune differences between pediatric and adult responses to SARS-CoV-2 is crucial for public health strategies.
Purpose of the Study:
- To compare antibody and cellular immune responses to SARS-CoV-2 between children (aged 3-11 years) and adults.
- To investigate the durability and cross-reactivity of immune responses in pediatric populations.
Main Methods:
- Comparative analysis of antibody titers and T cell responses against SARS-CoV-2 spike protein.
- Assessment of immune responses in both infected and seronegative children and adults.
- Longitudinal evaluation of immune memory at 6 and 12 months post-infection.
Main Results:
- Children demonstrated higher spike-specific T cell responses and sustained antibody levels compared to adults.
- Pre-existing cross-reactive immune responses to seasonal coronaviruses were observed in children.
- Immune responses in children remained robust at 6 and 12 months, while adults showed some waning.
Conclusions:
- Children mount vigorous, cross-reactive, and durable immune responses to SARS-CoV-2, primarily targeting the spike protein.
- These findings explain the generally milder clinical course of COVID-19 in pediatric populations.
- Results may inform the development of effective pediatric SARS-CoV-2 vaccination strategies.
Abstract:
SARS-CoV-2 infection is generally mild or asymptomatic in children but a biological basis for this outcome is unclear. Here we compare antibody and cellular immunity in children (aged 3-11 years) and adults. Antibody responses against spike protein were high in children and seroconversion boosted responses against seasonal Beta-coronaviruses through cross-recognition of the S2 domain. Neutralization of viral variants was comparable between children and adults. Spike-specific T cell responses were more than twice as high in children and were also detected in many seronegative children, indicating pre-existing cross-reactive responses to seasonal coronaviruses. Importantly, children retained antibody and cellular responses 6 months after infection, whereas relative waning occurred in adults. Spike-specific responses were also broadly stable beyond 12 months. Therefore, children generate robust, cross-reactive and sustained immune responses to SARS-CoV-2 with focused specificity for the spike protein. These findings provide insight into the relative clinical protection that occurs in most children and might help to guide the design of pediatric vaccination regimens.
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