19 Mar 2021
Beyond COVID-19: Immunity to human coronaviruses
Written by Dr Jennifer Juno
SARS-CoV-2 has quickly become the most well-known coronavirus, but it’s far from the first member of this family of viruses to infect humans.
Four viruses, known as endemic human coronaviruses, circulate worldwide and can cause the common cold.
Most people are first exposed to these viruses during childhood and are intermittently re-infected as adults.
Some experts have speculated that, when most of the world is immune to severe COVID-19 infection, SARS-CoV-2 may ultimately continue to circulate and cause mild re-infection similar to other human coronaviruses.
My team and I have now studied the nature of the immune response to these four human viruses, in an effort to understand long-term immunity to coronaviruses.
The study, published today in Clinical and Translational Immunology, finds that almost all adults show evidence of both antibody and T cell responses to these viruses, although often at relatively low levels.
This provides evidence that the immune system can remember encounters with coronaviruses, even if they cause only very mild illness.
One key finding of the study was that immune cells recognising coronaviruses were present not only in the circulation, but also in lymph nodes located close to the lung.
This suggests that maintaining immune responses in tissue sites near the respiratory tract may be an important component of long-term immune memory to coronaviruses and other respiratory viruses.
"These results will be useful in guiding future studies of COVID-19 vaccine responses and immunity to other respiratory viruses."