Common cold antibodies, created by the immune system and found much more commonly in children aged between 6-16, could provide some protection against COVID-19.
This is according to research from the UCL Great Ormond Street Institute of Child Health (ICH), Great Ormond Street Hospital (GOSH) the Francis Crick Institute and Imperial College London.
When infected with a virus, the immune system will create antibodies to help fight the virus. The antibodies will remain in the blood, able to fight that virus again more quickly if it returns.
In the research, published in Science, scientists found that some people, notably children, have antibodies reactive to SARS-CoV-2 in their blood, despite not ever having being infected with the virus. These antibodies are likely the result of exposure to other coronaviruses, which cause a common cold and which have structural similarities with SARS-CoV-2.
The researchers made this discovery while developing highly sensitive antibody tests for COVID-19. To see how well their assay tests were performing, they compared the blood of patients with COVID-19 to patients who had not had the disease. Surprisingly, they found that some people who had not been exposed to SARS-CoV-2 had antibodies in their blood which would recognise the virus. To confirm their findings, they analysed over 300 blood samples collected before the pandemic, between 2011 and 2018.
Nearly all samples had antibodies that reacted with common cold coronaviruses, which was expected given that everyone has been exposed to these viruses at some point in their lives. However, a small fraction of adult donors, about 1 in 20, also had antibodies that cross-reacted with SARS-CoV-2, and this was not dependent on recent infection with a common cold coronavirus.
In the lab, the researchers tested the antibodies they found in blood from uninfected people to confirm they are able to neutralise SARS-CoV-2. They found the antibodies targeted a particular part of the virus - the S2 subunit of the spike protein - found on its surface.
Co-author, Professor Lucy Wedderburn, Deputy Director of the National Institute of Research (NIHR) GOSH Biomedical Research Centre (BRC and Director of the Centre for Adolescent Rheumatology Versus Arthritis, said: “We were delighted to collaborate with the researchers at the Crick in this important study. We know that children seem to suffer far less from the SARS-CoV2 virus, so our study may give insights into how the immune system can protect us against COVID-19. And the more we understand about why children are at lower risk, we can be more confident in advising families about going to school or participating in other activities."
“Importantly, the work with Professor George Kassiotis and his team at the Crick is ongoing, to find out whether our young patients with arthritis and related rheumatic diseases also have these protective antibodies from previous coronavirus infection, that could help to protect them against COVID-19.”
A large study is now underway by researchers at UCL, the Crick and Imperial College London, to uncover the role that different antibodies and other immune defences play in protection against COVID-19 and how severely ill people become.
The Adolescent Rheumatology Versus Arthritis at UCL, UCLH and GOSH is supported by Versus Arthritis and Great Ormond Street Hospital Children's Charity.