A research team from Nagoya University (Japan) has recently published a study in Nature Communications that sheds light on the impact of human behavior on the evolution of new strains of SARS-CoV-2, the virus responsible for Covid-19. The study found that viral load, which refers to the amount or concentration of a virus present per ml of body fluid, plays an important role in the transmission of SARS-CoV-2.
The researchers used mathematical models with an artificial intelligence component to analyze previously published clinical data and discovered that successful SARS-CoV-2 variants had an earlier and higher peak in viral load, as well as a shorter duration of infection. They also found that the decreased incubation period and higher proportion of asymptomatic infections recorded as the virus mutated affected its evolution.
Professor Shingo Iwami, who led the research group, suggests that human behavior changes designed to limit transmission were increasing selection pressure on the virus. This caused SARS-CoV-2 to be transmitted primarily during the asymptomatic and pre-symptomatic periods, which occur earlier in its infectious cycle. As a result, the peak viral load advanced to this period to spread more effectively in the earliest stages before symptoms appear.
The study provides valuable insights into how human behavior can influence disease evolution patterns and highlights the importance of considering these factors when developing public health strategies to control outbreaks. The findings suggest that future studies should focus on understanding how different human behaviors affect disease evolution and transmission dynamics.