It turned out that people were able to resist the disease, which is caused by the SARS-CoV-2 virus, because they had a unique immune response. It helps them avoid infection.
It seems that a localised immune response in the lining of the nose allows them to identify the virus at an early stage and prevent it from establishing itself and causing infection.
As part of the collaborative study led by the college, samples from the subjects were analysed before and immediately after their exposure to the virus to study their immune response in detail.
In some people, previously unknown immune responses were observed that allowed them to resist prolonged viral infection. This gives detailed insight into the cell types involved.
The researchers say the British Covid-19 Human Challenge study serves as the most comprehensive chronology to date of the body's responses when first exposed to Covid or any other infectious disease.
Professor Christopher Chiu, study leader, said, "This paper highlights the value of the powerful, cutting-edge approaches applied through collaboration in the world's first SARS-CoV-2 Human Challenge study. This research program continues to provide unique insights into how the immune system protects us from infections that cannot be achieved in other settings. These findings will not only have important implications for the development of next-generation interventions for SARS-CoV-2, but should be generalizable to other future epidemics and pandemics."
As part of the study, 36 healthy adult volunteers were given the SARS-CoV-2 virus through the nose.
The researchers performed detailed blood and mucosal nasal monitoring on 16 volunteers. They tracked the entire infection as well as the activity of immune cells before the infection itself.
Some people immediately cleared the virus without exhibiting the typical widespread immune response, and instead developed subtle, previously unseen immune responses in their noses.
In contrast, the six individuals who developed persistent infection from Covid had a rapid immune response in the blood but a slower immune response in the nose. This allowed the virus to establish itself there.
"These findings shed new light on crucial early events that either allow the virus to take hold or clear it quickly before symptoms appear. We now have a much better understanding of the entire spectrum of immune responses, which can serve as a basis for developing potential treatments and vaccines that mimic these natural protective responses," said Dr. Marko Nikolic, the study's senior author and an honorary consultant in respiratory medicine. | BGNES
