London, United Kingdom – Scientists in London have made groundbreaking discoveries in understanding why some individuals are able to ward off Covid-19 infection more effectively than others. A study conducted at University College London revealed fascinating insights into the immune response of individuals who were able to resist Covid-19 even after being deliberately exposed to the virus.
Given a small nasal dose of the Covid-19 virus, healthy adults in the study displayed a swift immune response in nasal cells, effectively combating the virus at its early stages before full infection set in. The study also found heightened activity in a specific gene that assists in alerting the immune system to the presence of viruses in individuals who did not succumb to the infection. Dr. Marko Nikolić, the senior author of the study and an honorary consultant in respiratory medicine at UCL, emphasized the impact of these findings on understanding how the virus either establishes itself in the body or is swiftly cleared before symptoms manifest.
The research, part of the UK Covid-19 Human Challenge study, involved 36 healthy adult volunteers who had not previously contracted Covid-19 nor received vaccines against the virus. These volunteers were exposed to a low dose of the virus through the nose in 2021, during the peak of the pandemic. By closely monitoring immune cell activity in the blood and nasal lining of 16 volunteers, researchers were able to observe a detailed timeline of immune responses pre, during, and post-infection.
The study identified three distinct groups among the participants: those who developed a sustained infection and fell ill, those who briefly tested positive without developing a full infection, and those who experienced an “abortive infection” where they never tested positive but showed signs of mounting an immune response. Further analysis revealed that individuals in the latter two groups exhibited high levels of activity in a gene known as HLA-DQA2, primarily found in antigen-presenting cells that signal danger to the immune system.
Published in Nature, the findings suggested that individuals with elevated activity in the HLA-DQA2 gene may possess a more efficient immune response to Covid-19, preventing the infection from breaching the body’s initial defense mechanisms. However, it was noted that these individuals were not completely immune, as some later contracted the virus in the community. The study highlighted the importance of rapid immune responses in nasal cells, showing that delayed responses allowed the virus to establish itself and cause full infection.
Researchers are optimistic that these findings could pave the way for the development of more effective treatments and vaccines that mimic the body’s natural protective responses. By unraveling the intricate mechanisms of immune responses to Covid-19, scientists aim to enhance our ability to combat the virus and potentially prevent future outbreaks.