Immunology: Immune response differences to SARS-CoV-2 in adults and children revealed

Differences in the immune response between children and adults infected with SARS-CoV-2 are detailed in a paper in Nature Communications. The research provides evidence for why children may experience milder forms of COVID-19 than adults.

The lack of specific antibodies against SARS-CoV-2 has led to its rapid global spread. Neutralising antibodies have an important protective role against the disease, but a coordinated cellular immune response has also been shown to be important in fighting the infection. SARS-CoV-2 infection in children often leads to a milder form of the disease than in adults, but the immune response underlying this is unclear.

Sophie Valkenburg and colleagues assessed the immune response following SARS-CoV-2 infection in 24 children and 45 adults in Hong Kong over six months, and a negative adult control group. The authors observed that infected children had lower T cell responses to SARS-CoV-2 when compared to infected adults. The authors also found that compared with adults, children had lower levels of antibodies to other beta coronaviruses (such as the virus responsible for the common cold) indicating different baseline levels of immunity. The authors suggest that a lack of prior immunity to beta coronaviruses and reduced T cell activation could lead to milder COVID-19 in children.

Although further research is needed to understand the protective role of T cells in COVID-19, the authors conclude that the findings may aid our understanding of the differing immune responses between adults and children.