Human behavior may have influenced the evolution of new strains of COVID-19, new AI models suggest.

Vaccination and immune pressures from previous infections are known to cause the emergence of new strains of virus, evolved to bypass our existing immunity. But research from Nagoya University in Japan suggests that our own behavior may have also directed this evolution.

Just like any other organism, viruses evolve over time. Those with survival advantages—like an ability to evade existing immunity—become the dominant strain in the gene pool. One evolutionary trade-off that viruses must consider is the concept of viral load.

Viral load refers to the amount of virus present in each milliliter of body fluid in an infected individual. A higher viral load means that the virus will be more easily transmitted to others. However, if the viral load gets too high, individuals may become too sick to transmit the infection. Therefore, the virus needs to find a perfect middle ground that allows then to be effectively transmitted without killing their host.