For those fortunate enough to have avoided COVID-19 for over four years, a newly discovered immune response may be the reason behind their resilience. A challenge trial conducted during the peak of the pandemic in 2021 involved exposing 36 young, healthy unvaccinated volunteers in the UK, who had never contracted COVID-19, to the virus through their nasal passages. While the original intent was to determine the minimum virus required to initiate an infection, further analysis was conducted on 16 participants. Researchers closely monitored various immune responses in the blood and nasal lining before and after exposure, providing valuable insights into the timing and location of immune reactions. However, only six out of the 16 participants actually fell ill, presenting a unique opportunity to study how some individuals were able to resist the virus despite being exposed to an infectious dose. The exact number of people who have managed to avoid COVID-19 remains uncertain, with recent data from the US CDC indicating that nearly 1 in 4 Americans had not been infected by the end of 2022.
2024-07-03 10:00:00
Source from www.sciencenews.org