28/10/2025
Ottawa, Ontario — Tuesday October 28, 2025
Children tend to experience milder symptoms from SARS-CoV-2 than adults, but the reasons behind this difference are still being explored. T cells play a key role in limiting disease severity and building immune memory that helps protect against future variants. While children are known to mount strong early immune responses, adults often show more prolonged inflammation, which may contribute to more severe illness.
A new study led by Anne Pham-Huy compared immune responses in unvaccinated children and adults several months after SARS-CoV-2 infection.
“Kids seem to clear the virus so quickly that their immune systems don’t build the same long-term memory that adults develop.” said Dr. Pham-Huy. “These findings could be important for shaping COVID-19 vaccine strategies for children, suggesting that children’s immune systems may need different or additional approaches to strengthen long-term protection against the virus.”
The team found that while antibody levels were similar across age groups, children had significantly lower T cell memory responses. Their immune profiles resembled those seen for seasonal coronaviruses, suggesting that children may clear the virus so efficiently that their immune systems don’t activate strong long-term T cell responses.
Future research will explore whether vaccination can help strengthen and extend immune memory in children, providing insights to guide pediatric vaccine recommendations and help build lasting protection.
This research gives us clues for better vaccine strategies to help children build long-term immunity, not just scaled-down versions of what we do for adults.