People who haven't been exposed to the novel coronavirus COVID-19 could have a certain level of built-in immunity to the pathogen.br CNN reports a new study suggests that T cells reactive to the virus could possibly help reduce the severity of the illness if the person does get COVID-19.br T cells are part of the immune system and help protect the body from infection.br In a sample of 68 healthy adults in Germany who had not been exposed to COVID-19, 35 had T cells in their blood that were reactive to the coronavirus.br According to CNN, the researchers were from various institutions in Germany and the United Kingdom.br They say such reactive T cells were "probably acquired in previous infections with endemic" coronaviruses.br Using this T cell memory from another-yet-similar infection to respond to a new infection is called 'cross-reactivity.