AP “China has a population that is very large and there’s limited immunity. And that seems to be the setting in which we may see an explosion of a new variant." “When we’ve seen big waves of infection, it’s often followed by new variants being generated," Ray said.
Experts said a partially immune population like China’s puts particular pressure on the virus to change. Ray compared the virus to a boxer that “learns to evade the skills that you have and adapt to get around those." One big unknown is whether a new variant will cause more severe disease.
Experts say there’s no inherent biological reason the virus has to become milder over time. “Much of the mildness we’ve experienced over the past six to 12 months in many parts of the world has been due to accumulated immunity either through vaccination or infection, not because the virus has changed" in severity, Ray said.
In China, most people have never been exposed to the coronavirus. China's vaccines rely on an older technology producing fewer antibodies than messenger RNA vaccines.